junction appraisal report

Ballasalla Bypass 13/08/2020

GB01T20C02.10988712

JUNCTION APPRAISAL REPORT

BALLASALLA BYPASS JUNCTION APPRAISAL REPORT

IDENTIFICATION TABLE

Client/Project owner Isle of Man Government

Project Ballasalla Bypass

Study Junction Appraisal Report

Type of document Final

Date 13/08/2020

Reference number GB01T20C02.10988712

Number of pages 60

APPROVAL

Version Name Position Date Modifications

3

Author G Moon Principal 12/08/2020

Checked by

G Moon Principal 12/08/2020

Approved by

S Livingstone Associate 13/08/2020

Ballasalla Bypass Junction Appraisal Report GB01T20C02.10988712

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TABLE OF CONTENTS

1. INTRODUCTION 6

1.1 BACKGROUND 6

1.2 OVERVIEW OF METHODOLOGY 8

2. EXISTING SITUATION 10

2.2 ROAD NETWORK 10

2.3 EXISTING TRAFFIC FLOWS 11

2.4 FUTURE YEAR TRAFFIC FLOWS 13

2.5 PEDESTRIAN PROVISION 14

2.6 CYCLE PROVISION 15

2.7 RESIDENTIAL PROPERTIES 15

2.8 TOPOGRAPHY 15

2.9 LEVEL CROSSING 15

2.10 TRAFFIC REGULATION ORDERS 16

3. OPTION GENERATION AND SIFTING 17

3.1 INTRODUCTION 17

3.2 ASSESSMENT OF ‘LONG LIST’ OF OPTIONS 17

3.3 OUTCOME 21

4. OPTION ASSESSMENT 22

4.2 JUNCTION ASSESSMENT TOOLS 22

4.3 COST ESTIMATES 23

4.1 SWEPT PATH ANALYSIS 23

4.2 OPTION 1 – FOUR ARM ROUNDABOUT 24

4.3 OPTION 2 – FOUR ARM SIGNALISED JUNCTION 26

4.4 OPTION 3 – TWO PRIORITY JUNCTIONS ON BYPASS ALIGNMENT 32

4.6 OPTION 4 – TWO LINKED SIGNALS ON BYPASS ALIGNMENT 35

5. PARAMICS MODELLING 40

5.1 INTRODUCTION 40

5.2 MAIN FINDINGS 40

5.3 CONCLUSION 44


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6. ROAD SAFETY AUDIT 45

6.1 INTRODUCTION 45

6.1 GENERAL RECOMMENDATIONS 46

6.2 OPTION 1 47

6.3 OPTION 2 48

6.4 OPTION 3 49

6.5 OPTION 4 50

7. SUMMARY AND CONCLUSION 52

7.1 SUMMARY 52

7.2 CONCLUSIONS 55


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LIST OF FIGURES

Figure 1.1 Location of Ballasalla 6 Figure 1.2 Ballasalla Road Network and Bypass alignment 7 Figure 1.3 Local Road Network and Land Ownership 8 Figure 2.1 Study area and design considerations 10 Figure 2.2 Base 2018 - AM peak hour traffic flows (pcu) 11 Figure 2.3 Base 2018 - PM peak hour traffic flows (pcu) 12 Figure 2.4 Base 2018 - AM peak hour HGV % 12 Figure 2.5 Base 2018 - PM peak hour HGV % 13 Figure 2.6 Future Year with Bypass - AM peak hour traffic flows (pcu) 13 Figure 2.7 Future Year with Bypass - PM peak hour traffic flows (pcu) 14 Figure 4.1 Option 1 Layout 24 Figure 4.2 Option 2 Layout 26 Figure 4.3 Option 2 Inter-visibility conflict 28 Figure 4.4 Option 2 Swept path conflict 29 Figure 4.5 Option 2 Signal Staging 30 Figure 4.6 Option 3 Layout 32 Figure 4.7 Option 4 Layout 35 Figure 4.8 Option 4 Signal Staging 37

LIST OF TABLES

Table 4.1 Option 1 – Future Year + Bypass (2028) Junction Modelling Results 25 Table 4.2 Option 2 – Future Year + Bypass (2028) Junction Modelling Results 31 Table 4.3 Option 3 – Future Year + Bypass (2028) Junction Modelling Results 33 Table 4.4 Option 4 – Future Year + Bypass (2028) Junction Modelling Results 38 Table 6.1 Road Safety Audit - General Recommendations 46 Table 6.2 Road Safety Audit – Option 1 Observations / Recommendations 47 Table 6.3 Road Safety Audit – Option 2 Observations / Recommendations 48 Table 6.4 Road Safety Audit – Option 3 Observations / Recommendations 50 Table 6.5 Road Safety Audit – Option 4 Observations / Recommendations 50


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1. INTRODUCTION

1.1 Background

1.1.1 SYSTRA Ltd (SYSTRA) has been commissioned by the Isle of Man Government (IoMG) to undertake a review of the junction options to connect the western end of the proposed Ballasalla bypass into the existing road network.

1.1.2 Ballasalla is a village located in the south of the island, close to the IoM Airport. As shown in Figure 1.1, the A7 (which links Ballasalla with Port Erin to the west), and the A5 (which links Douglas to the north with the airport to the south) pass through the village.

Figure 1.1 Location of Ballasalla

1.1.3 Traffic flows within the village are particularly heavy on the A5, as vehicles travel between Douglas to the north and the IoM Airport and Castletown to the south. This places particular pressure on the A5 / A7 roundabout in the centre of the village, and contributes to congestion, noise and pollution within residential areas.

1.1.4 The proposed Ballasalla bypass has been designed to relieve traffic pressure within the village, as well as supporting future commercial and residential development. The exact alignment of the link has not been confirmed, but the bypass will pass around the south of the village connecting the current A5 in the east with the current A5 in the vicinity of Balthane Road, as shown in Figure 1.2.


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Figure 1.2 Ballasalla Road Network and Bypass alignment


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1.1.5 Figure 1.3 shows the local road network in the vicinity of Balthane Road, as well as the land that is owned by IoMG (Blue) and Malew Commissioners (Red).

Figure 1.3 Local Road Network and Land Ownership

1.1.6 The bypass alignment shown in Figure 1.3 is indicative only, and there is flexibility to alter this to best tie in with each identified junction option.

1.2 Overview of Methodology

1.2.1 As agreed with IoMG, the study has been undertaken using the following methodology:

Base (2018) and Future Year (2028) traffic flows in the AM and PM peak hours have been extracted from the IoM Paramics model .

A ‘long-list’ of potential junction options has been identified, and then sifted using a high level appraisal to identify the strongest options to take forward. Signalised, priority and roundabout options have been considered.

DMRB Stage 1 junction layouts have been developed in AutoCAD, where elements such as pedestrian and cycle provision have been incorporated. Where DMRB Design Standards cannot be met, departures have been noted.

Junction capacity assessment has been undertaken on these options using industry-standard software.


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Indicative costs have been prepared, based on industry standard construction rates, and from past involvement in delivering works similar to those proposed.

Each of the options to emerge from the study has been tested within the IoM Paramics model, and their comparative performance assessed.

Finally, each of the Preliminary Design options has then been assessed as part of an independent Road Safety Audit.

1.2.2 As requested by IoMG, the primary considerations for each option have been safety and operational performance, with additional aspects such as cost and land-take also being considered. The provision of enhanced pedestrian and cycling facilities has been considered within the assessment.


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2. EXISTING SITUATION

2.1.1 Figure 2.1 provides an overview of the study area, and highlights some of the main considerations in the junction design exercise.

Figure 2.1 Study area and design considerations

2.2 Road Network

2.2.1 The road network in the study area comprises:

The A5, defined as a ‘Primary’ link within the Manual for Manx Roads1 (MMR). Primary roads are defined as ‘Multi-Modal links. Strategic routes linking urban centres and major routes within built up areas’. Within the study area, the A5 is a wide single carriageway road with a speed limit of 30mph.

Balthane Road, defined as a ‘Local’ link within the MMR. This means that it is a multi-modal distributor road linking a district route to local roads. Within the study area, Balthane Road is a single-carriageway road with a speed limit of 30mph. Running south from the A5, Balthane Road provides access to the commercial and industrial area to the north of the airport.

1 ‘A Design and Construction Guide’ V1.03 published December 2017


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2.2.2 The A5 / Balthane Road roundabout is a three-armed mini roundabout, with Balthane Road forming the eastern arm. Both of the A5 arms have one lane on approach. Balthane Road also has a single lane, plus a short flare.

2.3 Existing Traffic Flows

2.3.1 The IoM Ballasalla Paramics model has been used to provide traffic flows for a Base Year of 2018, and for 2028 future years with and without the proposed bypass in place.

2.3.2 Traffic flows for the Base 2018 AM (08:00-09:00) and PM (17:00-18:00) peak hours are presented in Figure 2.2 and Figure 2.3 below. Flows are presented in passenger car units (pcu).

Figure 2.2 Base 2018 - AM peak hour traffic flows (pcu)

2.3.3 Figure 2.2 shows that in AM peak hour, traffic flows on the A5 are predominantly from south to north. Approximately 20% of A5 traffic (north and south) turns into Balthane Road. Flows emerging from Balthane Road are relatively low.


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Figure 2.3 Base 2018 - PM peak hour traffic flows (pcu)

2.3.4 Figure 2.3 shows that in PM peak hour, traffic flows on the A5 are lower than in the AM peak, and split relatively evenly between northbound and southbound traffic.

2.3.5 Only 81 pcu turn into Balthane Road, but flows emerging from Balthane Road are slightly higher than in the AM peak hour.

2.3.6 Figure 2.4 shows the percentage of HGV traffic on each arm in the AM peak hour in the Base 2018 scenario.

Figure 2.4 Base 2018 - AM peak hour HGV %

Figure 2.4 shows that the percentage of HGVs on the A5 arms in the AM peak is relatively low. In absolute terms there are less than 20 HGV movements on each of the A5 arms. The percentage of HGV traffic on Balthane Road is higher, but in absolute terms this equates to 20 HGV movements, so not a particularly significant number.

2.3.7 Figure 2.5 shows the percentage of HGV traffic on each arm in the AM peak hour in the Base 2018 scenario.


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Figure 2.5 Base 2018 - PM peak hour HGV %

Figure 2.5 shows that the percentage of HGVs on all arms of the junction are very low in the PM peak hour. In absolute terms, only 9 HGV movements occur at the junction in the PM peak hour.

2.4 Future Year traffic flows

2.4.1 Future year traffic flows with the proposed bypass in place have been extracted from the 2028 IoM Ballasalla Paramics model.

2.4.2 Traffic flows for the 2028 ‘with bypass’ AM (08:00-09:00) and PM (17:00-18:00) peak hours are presented in Figure 2.6 and Figure 2.7 below. Flows are presented in passenger car units (pcu).

Figure 2.6 Future Year with Bypass - AM peak hour traffic flows (pcu)

2.4.3 Figure 2.6 shows that in the 2028 AM peak hour, the predominant traffic flow is expected to be from west to east, from the A5 south onto the new bypass. 167 pcu are expected to turn right from the A5 south onto Balthane Road.


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Figure 2.7 Future Year with Bypass - PM peak hour traffic flows (pcu)

2.4.4 Figure 2.7 shows that in PM peak hour, traffic flows on the A5 south and new bypass are expected to be lower than in the AM peak hour.

2.5 Pedestrian Provision

2.5.1 Narrow footways are present on both sides of the A5. To the south of Balthane Road, the footway on the west of the A5 is ~2m in width, and the footway on the east of the road is 1.5m in width. No verges are present.

2.5.2 To the north of Balthane Road, the footways on both sides of the A5 narrow considerably. The footway to the west of the road is slightly set back from the road, and rises up a bank, and is ~1m in width. Steps are present before the footway reaches the level crossing, meaning that wheelchair users, and those with buggies are not able to use this route.

2.5.3 The footway to the east of the A5, that passes in front of the residential properties, is also ~1m in width, but has a flatter gradient. Beyond the level crossing, the eastern footway narrows to much less than 1m, and again would not be passable by wheelchair users, or those with buggies.

2.5.4 Mobility impaired users in wheelchairs, or those with buggies, are likely to find the western footway too narrow and steep (and the steps un-manageable), and the eastern footway too narrow.

2.5.5 Pedestrians with no mobility problems can use footways on both sides of the A5, although the presence of steps with steps, narrow footways and uneven surfacing (particularly as the A5 crosses the railway) require care to be taken.


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2.5.6 Pedestrian access along the A5 is therefore extremely poor, and exacerbated by the fact that the A5 provides the only access route across the railway within Ballasalla.

2.5.7 A footway is present on the south side of Balthane Road, running east away from the A5.

2.5.8 No pedestrian count data was available to inform the study.

2.6 Cycle Provision

2.6.1 There are no cycle facilities on either the A5 or on Balthane Road.

2.6.2 No cycle count data was available to inform the study.

2.7 Residential Properties

2.7.1 There are eight semi-detached properties to the east of the A5 between Balthane Road and the level crossing. Balthane Cottage is situated directly to the east of the A5 / Balthane Road roundabout.

2.8 Topography

2.8.1 No detailed topographical information is available at present. SYSTRA’s general observations are:

There appears to be a height difference of ~2m-3m between the A5 and the grassed woodland area to the west of the road.

Balthane Cottage sits at, or slightly below the level of the A5 / Balthane Road roundabout.

The row of eight semi-detached properties to the east of the A5 appear to sit slightly above the level of the road.

2.8.2 The above observations suggest that construction of any junction improvements will be more straight-forward to the east of the A5, rather than the west.

2.9 Level Crossing

2.9.1 The IoM steam railway operates between Douglas, Castletown and Port Erin between March and October. During this period, there are normally 4 trains per direction per day, rising to 6 trains per direction each day on 20 days, representing busy times on the island.

2.9.2 The railway crosses the A5 at a point 80m to the north of the A5 / Balthane Road roundabout. A level crossing with automatic barriers and warning lights is in place, and yellow box markings are in place over the crossing area. It is not known how long the barriers are down for each time a train passes.

2.9.3 An advanced warning sign and warning lights are provided on the A5, some 140m to the south of the crossing. Lights are provided at this location, as the crossing lights are not visible when travelling from this direction due to the left-hand bend in the road.


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2.10 Traffic Regulation Orders

2.10.1 There are no parking restrictions on either Balthane Road, or on the A5 between the A5 / Balthane Road roundabout and the level crossing.

2.10.2 Immediately to the south of Balthane Road, the A5 becomes a ‘Clearway’, where, no stopping or parking is permitted.


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3. OPTION GENERATION AND SIFTING

3.1 Introduction

3.1.1 This section sets out the initial long-list of junction options that were developed, and presents the results of an appraisal / sifting process that was used to identify the options carried forward into more detailed junction modelling and the preliminary design stage.

3.2 Assessment of ‘Long List’ of options

3.2.1 Following a review of the baseline situation, a ‘long list’ of options was drawn up, and was then ‘sifted’ using a combination of high level junction modelling, and a consideration of the following main factors:

Junction operation / likely efficiency; Required land take (linked to cost); Benefits to Pedestrian / Cyclists; and Safety considerations.

3.2.2 The assessment process has assumed that signalised junctions are slightly safer than roundabout options in terms of road safety (having a lower accident rate per vehicle km). Signalised junctions were also assumed to have greater benefits for pedestrians and cyclists, as they can incorporate pedestrian facilities and phases within the signal staging, as well as providing advanced stop lines for cyclists.

3.2.3 The options that were assessed are presented in the following table. Figure 3.1. The options comprise Roundabout (R), Signalised (S) and Priority (P) options.


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Option 1 Option R2

Four-arm roundabout between A5, Balthane Road and new bypass. Potential to provide left-turning slip from

existing A5 onto bypass.

+ Efficient configuration and use of space + Efficient alignment for bypass traffic

+ Makes good use of existing carriageway + Minimises disruption to properties to east of A5

~ Small amount of land take likely required to west of A5

in raised area with mature trees ~ Roundabouts cannot incorporate pedestrian / cycle

facilities ~ Potentially challenging to produce compliant design in

this location

CARRIED FORWARD

Four-arm roundabout or signalised junction, with current A5 north arm re-aligned to

provide greater separation.

Would require use of existing A5 to serve properties, and need to tie back in prior to

level crossing

+ Better arm separation / configuration than 1 + Minimises disruption to properties to east of

A5

~ More land-take required to west of A5 ~ Higher construction costs than 1

~ Roundabouts cannot incorporate pedestrian / cycle facilities

~ Potentially challenging to produce compliant design in this location

NOT CARRIED FORWARD ON BASIS OF GREATER LAND TAKE THAN 1


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Option R3 Option R4

Two junctions on the existing A5 alignment.

R3 option would involve retention of the existing A5 / Balthane Roundout, and creation of a new

roundabout between existing A5 and bypass.

+ Existing A5 / Balthane junction could potentially remain unchanged

+ Efficient use of existing A5 carriageway

~ Less efficient route for bypass traffic ~ Not a lot of separation between the two junctions,

concentrating vehicle movements in small area. ~ Land to west of A5 outside highway boundary

requried ~ Roundabouts cannot incorporate ped / cycle

facilities ~ Potential issues with forward visibility to / from

the new junction and level crossing.

NOT CARRIED FORWARD ON BASIS OF LAND TAKE, INEFFICIENT BYPASS ROUTING, JUNCTION

SEPARATION AND FORWAD VISIBILITY

Two junctions on the alignment of the new bypass.

R4 option would involve reconfiguration of the existing A5 / Balthane Roundout, and creation of

new roundabout between existing A5 and bypass.

+ Efficient routeing of bypass traffic

~ Realigned A5 would cut right through existing properties

~ Not a lot of separation between the two junctions, concentrating vehicle movements in small area. ~ Roundabouts cannot incorporate ped / cycle

facilities

NOT CARRIED FORWARD ON BASIS OF JUNCTION SEPARATION, AND CONCENTRATION OF

UNCONTROLLED TRAFFIC MOVEMENTS IN SMALL SPACE


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Option 2 Option S2

Four-arm signalised junction. Option to provide left-turning slip from existing A5 onto bypass.

+ Efficient configuration and use of space

+ Efficient alignment for bypass traffic + Makes good use of existing carriageway

+ Minimises disruption to properties to east of A5 + Potential to provide priority to bypass traffic within

signal staging + Allows incorporation of signalised pedestrian crossings,

and advanced stop lines for cyclists.

~ Potentially challenging to produce compliant design in this location

CARRIED FORWARD

Two signalised junctions on the existing A5 alignment.

Option S2 would involve the creation of a new signalised junction, and conversion of the A5 /

Balthane Road roundabout to signals.

+ Makes good use of existing carriageway

~ Inefficient routeing for bypass traffic ~ Concentrates traffic movements in a small

area ~ New junction in very close proximity to level

crossing – potential safety issue ~ Initial junction modelling indicates insufficient spacing between two junctions to allow signals

to operate efficiently.

NOT CARRIED FORWARD ON BASIS OF SAFETY ISSUES, INEFFICIENCY AND LIKELY CAPACITY

ISSUES


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Option 3 Option 4

Two linked signalised junctions on the bypass alignment. Option to use existing A5 as a one-way

link between Balthane Road and old A5.

+ Efficient alignment for bypass traffic + Potential to provide priority to bypass traffic within

signal staging + Allows incorporation of signalised pedestrian

crossings, and advanced stop lines for cyclists.

~ Need to provide sufficient space between signalised junctions to allow efficient operation.

CARRIED FORWARD

Two priority junctions on the bypass alignment. Option to use existing A5 as a one-way link between

Balthane Road and old A5.

+ Efficient alignment for bypass traffic + Best priority for bypass traffic of all the options

which would have priority all the way

~ Does not allow incorporation of signalised pedestrian crossings, and advanced stop lines for

cyclists. ~ Priority junctions not as safe for emerging traffic

from minor arms.

CARRIED FORWARD

3.3 Outcome

3.3.1 The initial generation and sifting of options has identified four options to take forward to the more detailed design stage:

Option 1 (R1) - Four-arm roundabout between A5, Balthane Road and new bypass; Option 2 (S1) - Four-arm signalised junction between A5, Balthane Road and new

bypass; Option 3 (P1)- Two priority junctions on the bypass alignment; and Option 4 (S3) - Two linked signalised junctions on the bypass alignment.


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4. OPTION ASSESSMENT

4.1.1 This section describes the Option Assessment that has been undertaken for each of the options to emerge from the sifting exercise. For each Option, the following information is presented:

An initial layout based on DMRB standards, and a description of the main features of the layout. Departures from Standards are noted. The junction layout drawings are presented in Appendix A.

Results of Junction Capacity modelling. Each junction has been tested using the ‘Future Year + Bypass’ traffic flows (2028) in both the AM and PM peak hours. Full model outputs are included within Appendix B.

An Initial Cost estimate.

4.1.2 A Stage 1 Road Safety Audit of each Option has also been completed. The findings of this audit are presented in Section 6.

4.2 Junction Assessment Tools

4.2.1 The following industry-standard software packages have been used to test the different junction options:

Signalised options - LINSIG v3; Roundabout options - JUNCTIONS v6 (Arcady module); and Priority options - PICADY

4.2.2 LINSIG results refer to the Degree of Saturation (DoS) and Mean Maximum Queue (MMQ) predicted for each lane at a junction. A DoS of 100% indicates that the lane in question is operating at its theoretical capacity (point of saturation), whilst a DoS of 90% or less indicates that the lane is operating within its practical capacity.

4.2.3 The MMQ is a combination of:

The vehicle queue at the end of the red period; Vehicles joining the back of the queue at the start of the green period; and Random / oversaturated queueing.

4.2.4 The ARCADY and PICADY analysis reports on the Ratio of Flow Capacity (RFC) and the maximum forecast queue for each movement within the junction. The RFC of an arm of a junction is one of the principal factors in influencing queues and delays. General engineering design principles, as set out in the DMRB, suggest that when assessing a priority junction or roundabout, RFC levels should not exceed 0.85 in order for the arm of a junction to operate within ‘practical’ capacity. Should the RFC level exceed 1.0 then the junction is operating above ‘theoretical’ capacity.

4.2.5 When the performance of an arm exceeds 1.0 RFC, the subsequent queue and delay information increases exponentially. For these instances, queue and delay values should not be compared, only simply agree that the junction is performing significantly over capacity.


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4.3 Cost Estimates

4.3.1 The cost estimates outlined attempt to portray realistic estimates from all available information, with costs extracted from industry standard construction rates (SPONS Civil Engineering and Highway Works Price Book 2019) and from past involvement in delivering works similar to those proposed within the intervention schemes. It would however, be prudent to note that the figures quoted are based on limited information and high level concept stage proposals.

4.3.2 They include an Optimism Bias allowance of 44%, which is the recommended upper figure for Civil Engineering projects set out in the HMG’s ‘Supplementary Green Book Guidance’ on Optimism Bias.

4.3.3 There are several unknowns related to the schemes, namely the location/depths of buried services with the potential requirement for diversion, ground conditions, drainage/ flood risk, environmental impacts, land ownership, structures, accommodation works and traffic management procedures. From past experience these unknowns tend to significantly impact a project both in terms of cost and program.

4.3.4 For the purposes of the estimations, and to portray as robust a figure as possible, a nominal allowance has been included were possible for potential diversion of existing utilities. This is an allowance, merely based on the type of works being proposed against likely utilities in the area, with no information/estimations provided by individual statutory undertakers. Detailed information should be sought in the form of a utilities search of the area to determine location/depths, with quotes to carry out potential diversionary works obtained from each individual provider in the area.

4.3.5 The estimations above are based on current proposals as outlined on the plans provided. Any change to the proposals will result in a change to the estimated value of the works and as such an amendment to these costs should be sought before progressing.

4.1 Swept Path Analysis

4.1.1 Swept path drawings have been produced for each option. The layouts have been tested using a 16.5m articulated HGV, which is the maximum legal length.


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4.2 Option 1 – Four arm roundabout

Layout

Figure 4.1 Option 1 Layout

4.2.1 Option 1 would provide a 4-arm roundabout with an ICD of 30m. Single lane approaches would be provided on all arms, with a left-turning bypass lane provided from Balthane Road. A small runover would be provided on the central island to allow HGVs to navigate the roundabout.

4.2.2 Signalized pedestrian crossings would be provided on all arms of the roundabout, remote from the junction. These would be located to provide suitable forward visibility to the crossing from all traffic streams, and set back from the roundabout to provide space for three vehicles leaving the roundabout to stack without blocking back onto the roundabout. In practice, this means that the crossings are not on pedestrian desire lines close to the roundabout, and so it is likely that guard rails would need to be put in place to deter un-controlled crossings.

4.2.3 Shared 3m footways / cycleways would be provided on the A5 north and Link Road arms, and would tie in with the existing footway network as show in Figure 4.1.


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4.2.4 The footway to the west of the A5, which is currently narrow and where there is a notable height difference between the footway and the road, would be upgraded and levelled.

4.2.5 This option would require a small portion of land to the west of the A5, and would require the removal of the existing kerbside parking on the east side of the A5, along with demolition of at least three properties.

Departures from Standards

4.2.6 This Option would require the following departures from DMRB CD 116 (Roundabouts).

- 6.0m exit width on Balthane Rd [7.0m] - 5.4m exit width on A5 South [7.0m] - 15.0m exit radius on Balthane Rd [40.0m] - 20.m exit radius on Ballasalla Bypass [40.0m] - 16.0m exit radius on A5 South [40.0m]

4.2.7 The achievable dimensions are stated first, and required standards are shown in [square brackets]. Black text indicates that departures are within the relaxation range accepted. Red text indicates that departures are outside of the absolute minimum.

Junction Capacity Modelling

4.2.8 Option 1 has been assessed using ARCADY. Table 4.1 presents the ARCADY assessment results for the AM and PM peak hours. The effect of the signalized pedestrian crossings on junction performance has been considered by utilising the ‘pedestrian crossing’ feature within ARCADY, which allows the user to code zebra crossings on each arm. The model assumes that one pedestrian crosses each arm every minute during the modelled hour.

4.2.9 Full ARCADY results are provided in Appendix B.

Table 4.1 Option 1 – Future Year + Bypass (2028) Junction Modelling Results

4.2.10 Table 4.1 shows that:

The roundabout is predicted to operate within practical capacity during the AM peak hour. The busiest arm is the A5 South, with an RFC of 0.76, indicating a reasonable amount of spare capacity before the practical capacity of 0.85 Is reached.

In the PM peak hour, the junction is predicted to operate well within practical capacity during the AM peak hour

This option therefore represents a viable option in terms of junction performance.


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Cost Estimate

4.2.11 The high-level cost estimate for this option is:

Total cost - £757,000 +VAT 44% Optimism Bias - £333,000 +VAT Total cost including Optimism Bias - £1,090,000 +VAT

4.3 Option 2 – Four arm signalised junction

Layout


4.3.1 Option 2 would provide a four-arm signalised junction between the A5, Balthane Road and the bypass. Single lane approaches would be provided on all arms, with the exception of the A5 south, where a short right-turn flare will also be provided, allowing a right-turn filter arrow to be incorporated into the signal timings.

4.3.2 Right-turns from the bypass onto the A5 north would be banned (less than 10pcu are predicted to make this movement in the AM and PM peak hours). Traffic wishing to enter Ballasalla from the east would remain on the old A5.

4.3.3 Signalised pedestrian crossings would be provided on all arms of the junction, and advanced cycle stop lines could be provided if required.


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4.3.4 Shared 3m footways / cycleways would be provided on the A5 north and Link Road arms, and would tie in with the existing footway network as show in Figure 4.2.

4.3.5 The footway to the west of the A5, which is currently narrow and where there is a notable height difference between the footway and the road, would be upgraded and levelled.

4.3.6 This option would require the removal of the existing kerbside parking on the east side of the A5, along with demolition of at least two properties.


4.3.7 This Option would require the following departures from DMRB CD 123 (At Grade Priority and Signalised Junctions).

- Junction inter-visibility zone conflicts with boundary of property located on east side of

Balthane Rd - Junction inter-visibility zone conflicts with boundary of property located on east side of A5

south. - Taper Length on A5 South 25.0m [70.0m]



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4.3.9 The visibility conflicts are shown in Figure 4.3.

Figure 4.3 Option 2 Inter-visibility conflict

4.3.10 Discussions with the Road Safety Auditor suggest that the inter-visibility conflicts, which primarily create a risk to pedestrians from left-turning traffic, could potentially be mitigated by either:

Ensuring that the stage in which vehicles turn left does not follow the pedestrian stage: or

Extending the pedestrian intergreen, to further ensure that the pedestrian crossing is clear before left-turning traffic is given a green signal.

4.3.11 There is a potential further minor inter-visibility zone conflict between the northbound stopline on the A5, and the A5 west stopline, where the line of visibility runs along the bank / treeline to the west of the road. Visibility appears to be borderline, but may be achievable. Trimming any over-hanging branches would improve the situation.

4.3.12 It is recommended that the IoM Government investigates whether additional land could be purchased to eliminate these inter-visibility issues.

4.3.13 Swept path analysis indicates that the swept path of a 16.5m HGV turning left out of HGV would bring it into conflict with any vehicle waiting to turn right into Balthane Road from the A5 south (and vice versa), as shown in Figure 4.4.


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Figure 4.4 Option 2 Swept path conflict

4.3.14 This situation has been discussed with the Road Safety Auditor. The signal staging that has been tested in the LINSIG model (see below) assumes that the left turn out of Balthane Road is called in a separate stage to the A5 south, meaning that there would be no direct conflict between left turning and right-turning traffic.

4.3.15 A conflict could potentially occur if (depending on staging):

Traffic waiting to turn right from the A5 south fails to clear in the allotted intergreen time before an HGV emerges from Balthane Road; or

A slow moving HGV turning left out of Balthane Road is slow to make the left turn onto the A5 south, meaning that the A5 south traffic stage could potentially begin before an HGV has completed this manoeuvre.

4.3.16 In both of these instances, this potential conflict could be removed by lengthening the intergreen time between the Balthane Road and A5 south stages. However, in SYSTRA’s opinion such a conflict is unlikely, as vehicles from both Balthane Road and the A5 are likely to spot any vehicles that are still within the junction completing a manoeuvre, and wait for the junction to clear before progressing.


4.3.17 Option 2 has been assessed using LINSIG. The following signal staging has been tested.


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Figure 4.5 Option 2 Signal Staging

4.3.18 The above signal staging assumes:

Right-turning vehicles turn in gaps in opposing traffic streams, with the exception of the A5 south arm, where right-turning traffic into Balthane Road is also provided with a right-turn filter.

An ‘all red’ pedestrian stage’.

4.3.19 Two network control plans have been tested:

A four-stage sequence (1,2,3,4 above) with a cycle time of 90s, where the pedestrian stage is called each cycle.

A seven stage, ‘double-cycled’ sequence (1,2,3,4,1,2,3) with a cycle time of 140s, where the pedestrian stage is called once in this period.

4.3.20 Table 4.2 presents the LINSIG assessment results for the AM and PM peak hours for both assessed control plans. Full LINSIG results are provided in Appendix B.

A

B

C

D

EF

1 Min: 7

A

B

C

D

EF

2 Min: 7

A

B

C

D

EF

3 Min: 4

A

B

C

D

EF

4 Min: 10


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If the pedestrian stage is not called, and the junction operates on a single 90s cycle, it is expected to operate well within capacity in the AM and PM peak hours, with maximum DoS of 69.1% on the A5 north in the AM peak hour.

In the AM peak hour, if the pedestrian stage is called every cycle, the junction is predicted to operate over capacity, with the A5 north and A5 south arms operating with DoS of 109.9% and 93.0% respectively.

When the junction is run on a ‘Double Cycle’, with the pedestrian stage called once every 140s, the junction is predicted to operate just under practical capacity in the AM peak hour. The A5 north and south arms are predicted to operate with DoS of 85.1% and 82.2% respectively, indicating a small amount of reserve capacity. Queues on the A5 south are predicted to be 20.9pcu (120m).

The junction is predicted to operate within practical capacity during the PM peak hour on a Single Cycle with pedestrian stage. The busiest arm is the bypass, with a DoS of 66.7%, indicating a reasonable amount of spare capacity before the practical capacity 90% is reached.

This option therefore represents a viable option in terms of junction performance, providing that pedestrian demand does not require the pedestrian stage to be called more than once every 140 seconds. It should be noted that even at this frequency there is not a great deal of spare capacity within the junction to cater for future traffic growth beyond that modelled.


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Cost Estimate


Total cost - £755,000 +VAT 44% Optimism Bias - £333,000 +VAT Total cost including Optimism Bias - £1,088,000 +VAT

4.4 Option 3 – Two priority junctions on bypass alignment


4.4.1 Option 3 would utilise the same road layout as Option 4, but the Balthane Road and A5 approaches would be configured as priority junctions.

4.4.2 At the Balthane Road junction, the A5 south approach would be one lane plus a short right-turn flare. The Balthane Road approach would be a single lane with short flare. Right-turns from the bypass towards Ballasalla would be banned.

4.4.3 At the north-eastern junction, a short right-turn flare would be provided for right-turning traffic towards Ballasalla. The minor road approach would comprise a single lane with short flare.

4.4.4 One potential option is to remove the ability to turn right from southbound bypass onto the A5 link. This would mean that the A5 link could be reconfigured as one way in an eastbound


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direction. The right-turn lane on the bypass could then be removed, saving road space (and cost).

4.4.5 Signalised pedestrian crossings would be provided on the A5 south, Balthane Road and the bypass approach to the eastern junction.

4.4.6 Shared 3m footways / cycleways would be provided on the A5 north and Link Road arms, and on the realigned A5 north between the railway line and the Link Road. These shared footways would tie in with the existing footway network as show in Figure 4.4.

4.4.7 This option would allow a significant improvement to be made to the footways on the western side of the old A5, and the area where the existing properties are located, between the old A5 and the eastern junction, could potentially be landscaped, or be used as some form of community greenspace.

4.4.8 This options would not necessarily require the removal of the existing kerbside parking on the east side of the A5, although it would require the probable demolition of six properties. The remaining properties would be surrounded by roads or the rail line on all sides.

4.5 This Option would require the following departures from DMRB CD 123 (At Grade Priority and Signalised Junctions).

- Taper Length on A5 South 35.0m [70.0m] Junction Capacity Modelling

4.5.1 Option 3 has been assessed using PICADY. Table 4.3 presents the PICADY assessment results for the AM and PM peak hours. Full PICADY results are provided in Appendix B.



The minor arms at both junctions (Balthane Road and the A5 north) are predicted to operate well within capacity in both the AM and PM peak hours.


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The right-turn movements into both minor arms are predicted to operate well within capacity in both the AM and PM peak hours.

This option therefore represents a viable option in terms of junction performance, and delivers the lowest delays for mainline A5 south-bypass traffic.

This should be balanced against the fact that this option does not offer integrated facilities for pedestrians and cyclists, and is a less safe option for traffic emerging from the minor arms of Balthane Road and A5 north.

Cost Estimate


Total cost - £1,060,000 +VAT 44% Optimism Bias - £466,000 +VAT Total cost including Optimism Bias - £1,526,000 +VAT


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4.6 Option 4 – Two linked signals on bypass alignment

Layout


4.6.1 Option 4 would provide two signalised junctions on the alignment of the bypass. The first would be formed at the A5 / Balthane Road / bypass junction, where the A5 south approach would be a single lane with short right-turn flare, and both the bypass and Balthane Road approaches would be single lane. The existing A5 carriageway would be retained as a one-way (northbound) link. Right-turns from the bypass onto this one-way link would be banned. Vehicles wishing to turn right into Ballasalla would use the junction to the north.

4.6.2 A second signalised junction would be formed to the north, between the old A5 and the new bypass. All arms would have a one lane approach, and the northern bypass arm would also have a short flare for right-turning traffic.

4.6.3 As per Option 3, a potential option is to remove the ability to turn right from southbound bypass onto the A5 link. This would mean that the A5 link could be reconfigured as one way in an eastbound direction.


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4.6.4 Signalised pedestrian crossings would be provided on the A5 south, Balthane Road and the bypass approach to the eastern junction. Advanced cycle stop lines could be provided on all approaches if required.

4.6.5 Shared 3m footways / cycleways would be provided on the A5 north and Link Road arms, and on the realigned A5 north between the railway line and the Link Road. These shared footways would tie in with the existing footway network as show in Figure 4.4.

4.6.6 This option would allow a significant improvement to be made to the footways on the western side of the old A5, and the area where the existing properties are located, between the old A5 and the eastern junction, could potentially be landscaped, or be used as some form of community greenspace.

4.6.7 This options would not necessarily require the removal of the existing kerbside parking on the east side of the A5, although it would require the probable demolition of six properties. The remaining properties would be surrounded by roads or the rail line on all sides.


4.6.8 This Option would require the following departures from DMRB CD 123 (At Grade Priority and Signalised Junctions).

- Junction inter-visibility zone conflicts with boundary of property located on east side of

Balthane Rd - Junction inter-visibility zone conflicts with boundary of property located on east side of A5

south. - Taper Length on A5 South 35.0m [70.0m]



4.6.10 Option 4 has been assessed using LINSIG, and modelled as two separate, but linked signalised junctions. The following signal staging has been tested.


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Figure 4.8 Option 4 Signal Staging

4.6.11 The above signal staging assumes:

Right-turning vehicles turn in gaps in opposing traffic streams. An ‘all red’ pedestrian stage’ at both junctions.

4.6.12 Three network control plans have been tested:

A two-stage sequence (1,2 above) with a cycle time of 100s, where the pedestrian stage is not called.

A three-stage sequence (1,2,3 above) with a cycle time of 120s, where the pedestrian stage is called each cycle.

A five stage, ‘double-cycled’ sequence (1,2,3,1,2) with a cycle time of 140s, where the pedestrian stage is called once in this period.

4.6.13 Table 4.4 presents the LINSIG assessment results for the AM and PM peak hours for both assessed control plans. Full LINSIG results are provided in Appendix B.

A

B

C

D

E

FGH

Stream 1

A

B

CG

1 Min: 7

A

B

CG

2 Min: 7

A

B

CG

3 Min: 12

A

B

C

D

E

FGH

Stream 2

D

E

F

H

1 Min: 7

D

E

F

H

2 Min: 7

D

E

F

H

3 Min: 12


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In both the AM peak hour, all of the approach arms are predicted to operate within capacity. If the pedestrian phase is not called, there is predicted to be a maximum DoS of 58.6% on the A5 south, with a resultant queue of 8.5 pcu (50m). If the pedestrian cycle is called once every 120s, DOS on the A5 south increases to 74.8%, with a MMQ of 21.7 pcu (125m). Double-cycling the junction to 140s does not offer any appreciable benefits to performance.

The modelling identifies an issue with queues on the internal links (i.e. the sections of the bypass between the signalised junctions). The results indicate MMQ of 11-12pcu on the internal links, which is a distance of 70m. The available distance between the two junctions is 60m, indicating that vehicles would potentially block back between the junctions.

In the PM peak hour, the junction is predicted to operate below capacity in all scenarios, AM peak hour, if the pedestrian stage is called every cycle, the junction is predicted to operate over capacity, with the A5 south and A5 north arms operating with DoS of 100.1% and 98.5% respectively.


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This option therefore would appear to represent a viable option in terms of junction performance, providing that the issue of queueing on the internal link can be suitably addressed. The application of a MOVA system (or similar) would provide a potential solution, where detectors on the internal link could trigger a ‘clear out’ phase should excess queuing be detected. Another options might be to place yellow box markings in each junction, preventing vehicles from entering the junction until the exit is clear. This would have the effect of slightly lengthening queues on the approach arms, as queuing vehicles are displaced. The Paramics model is best-placed to examine this effect.

Cost Estimate


Total cost - £1,114,000 +VAT 44% Optimism Bias - £490,000 +VAT Total cost including Optimism Bias - £1,604,000 +VAT


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5. PARAMICS MODELLING

5.1 Introduction

5.1.1 Each of the four junction options has been tested using the 2018 Ballasalla Paramics Model, which covers the settlement and its surrounding road network.

5.1.2 The 2018 Base model was developed for the following time periods.

AM period (07:00-10:00) IP Period (11:00-14:00) PM Period (16:00-19:00)

5.1.3 In May 2019 the DoI commissioned SYSTRA to use the model to test the traffic impacts of the proposed housing developments to the south of Douglas Road in Ballasalla,

5.1.4 This work saw the development of a 2028 Reference Case Model and included both the Phase 1 and Phase 2 developments proposed for area. This work was reported in the Ballasalla Paramics Discovery Model – Douglas Road, Ballasalla Development Testing (Phases 1 and 2), SYSTRA Ref. GB01T17L96/CSSCDE35/002, May 2019.

5.1.5 The 2028 Future Year Model has been used for the purposes of this study to assess each of the proposed junction design layouts.

5.1.6 The following results were output from the modelling exercise for the purposes of the study.

General Network Operation Average Maximum Queue Lengths (at selected junctions) Journey Times (along selected routes)

5.1.7 The results presented in this section are based on the model run separately 5 times, for each period, using a random seed. The results were then averaged across all runs.

5.2 Main Findings

5.2.1 The Paramics results are presented in detail in the separate ‘IoM Ballasalla Junction Design Testing Report’. The following section summarises the main findings of the modelling exercise.

5.2.2 In each of the tested options, the introduction of the bypass, and the roundabout at the bypass/A5 junction to the east of Ballasalla causes queues to develop, especially on the A5 eastbound in the AM peak hour,, and on the bypass in the PM peak hour.

Option 1 (Roundabout)

AM Period

5.2.3 With Option 1 in place, the network was shown to operate well during the 2028 AM period. Operational queueing was shown to periodically develop on the north arm of the roundabout junction, but this was not shown to be significant.


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5.2.4 The roundabout in the centre of Ballasalla was also shown to operate well throughout the 2028 AM period, with no significant queues developing on any of the approach arms.

5.2.5 The roundabout junction on Douglas Road where the proposed Bypass connects with the A5 operated well throughout the 2028 AM Period. Operationally, queues were shown to periodically develop on Douglas Road, eastbound towards Douglas, where trips give way to traffic from the proposed Bypass. These queues were not shown to be significant or cause any network issues during the AM period simulation.

IP Period

5.2.6 The network was shown to operate well throughout the entire IP period with no queueing issues highlighted on any of the approach arms to the roundabout junction (Option 1) on the A5 at Balthane Road, within Ballasalla or on Douglas Road at the north end of the proposed Bypass.

PM Period

5.2.7 The roundabout junction as part of Option 1 was shown to operate well throughout the 2028 PM period with no significant queues predicted to form on any of the approach arms.

5.2.8 The roundabout in the centre of Ballasalla was also shown to operate well throughout the 2028 PM period, with no significant queues predicted to develop on any of the approach arms.

5.2.9 The roundabout junction at the north end of the proposed Bypass was also shown to operate well throughout the 2028 PM period, with some operational queues developing on the Bypass approach arm periodically.

Option 2 (Signalised Crossroads)

AM Period

5.2.10 With Option 2 in place, the network was shown to operate well during the 2028 AM period. Queueing was shown to develop on each arm of the signalised crossroads, but given it is under signal control this was expected.

5.2.11 The roundabout in the centre of Ballasalla was also shown to operate well throughout the 2028 AM period, with no significant queues developing on any of the approach arms.

5.2.12 The roundabout junction on Douglas Road where the proposed Bypass connects with the A5 operated well throughout the 2028 AM Period. Operationally, queues were shown to periodically develop on Douglas Road, eastbound towards Douglas, where trips give way to traffic from the proposed Bypass. These queues were not shown to be significant or cause any network issues during the AM period simulation. Periodically, operational queues were also shown to develop on the proposed Bypass arm of the junction also, but these were not shown to be significant and were shown to quickly dissipate.


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IP Period

5.2.13 The network was shown to operate well throughout the entire IP period with no queueing issues highlighted on any of the approach arms at the roundabout junction within Ballasalla or the roundabout junction on Douglas Road at the north end of the proposed Bypass. Some operational queues were shown to develop at the signalised crossroads on the A5 at Balthane Road, but these were not shown to be operational only as a result of the signal control introduced in this area of the road network.

PM Period

5.2.14 In general, the signalised crossroads junction (Option 2) was shown to operate well throughout the 2028 PM period. Queues were shown to develop on each arm, but these were controlled with the signal control in place, which were shown to work well during the entire modelled period.

5.2.15 The roundabout in the centre of Ballasalla was shown to operate well throughout the 2028 PM period, with no significant queues predicted to develop on any of the approach arms.

5.2.16 The roundabout junction at the north end of the proposed Bypass was also shown to operate well throughout the 2028 PM period, with some operational queues developing on the Bypass approach arm, but these were shown to be periodic only.

Option 3 (Staggered Priority)

AM Period

5.2.17 With Option 3 in place, the network was shown to operate well during the 2028 AM period. No significant queueing was predicted to develop on any of the approach arms of the staggered priority junction arrangement modelled, or on any of the approach arms at the roundabout junction in the centre of Ballasalla.

5.2.18 The roundabout junction on Douglas Road where the proposed Bypass connects with the A5 also operated well throughout the 2028 AM Period. Operationally, queues were shown to periodically develop on Douglas Road, eastbound towards Douglas, where trips give way to traffic from the proposed Bypass.

IP Period

5.2.19 During the IP period, the network was shown to operate well throughout with no queueing issues highlighted on any of the approach arms at the staggered priority junction, the roundabout junction within Ballasalla or the roundabout junction on Douglas Road at the north end of the proposed Bypass.

PM Period

5.2.20 The staggered priority junction (Option 3) was shown to operate well throughout the 2028 PM period, with no significant queues predicted to form on any of the approach arms throughout the PM period simulation.


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5.2.22 The roundabout junction at the north end of the proposed Bypass was also shown to operate well throughout the 2028 PM period, with some operational queues developing on the Bypass approach arm, but these were shown to be periodic only.

Option 4 (Staggered Signal Control)

AM Period

5.2.23 With Option 4 in place, the network was shown to operate well during the 2028 AM period. Queues were predicted to develop on each of the approach arms of the staggered signal control junction, but these were not shown to significantly impact on the rest of the road network.

5.2.24 The approach arms at the roundabout junction in the centre of Ballasalla were all shown to work well during the 2028 AM period with no significant queues predicted form throughout the entire AM period.

5.2.25 The roundabout junction on Douglas Road where the proposed Bypass connects with the A5 also operated well throughout the 2028 AM Period. Operationally, queues were shown to periodically develop on Douglas Road, eastbound towards Douglas, where trips give way to traffic from the proposed Bypass, and on the proposed Bypass arm itself. These queues were not however shown to cause any significant issues on the rest of the road network.

IP Period

5.2.26 During the IP period, the network was shown to operate well throughout the entire modelled period with no queueing issues highlighted on any of the approach arms at the staggered signal controlled junction, the roundabout junction within Ballasalla or the roundabout junction on Douglas Road at the north end of the proposed Bypass.

PM Period

5.2.27 The staggered signal controlled junction (Option 4) was also shown to operate well throughout the 2028 PM period, with no significant queues predicted to form on any of the approach arms throughout the PM period simulation. The signal control in place was shown to operate well.


5.2.29 The roundabout junction at the north end of the proposed Bypass was shown to operate with no significant queueing issues throughout the 2028 PM period. Some operational queues were shown to develop on the Bypass approach arm, but these were shown to be periodic only.


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5.3 Conclusion

5.3.1 The testing undertaken using the Ballasalla Paramics Discovery Model has found that each of the four proposed options works satisfactorily throughout each modelled period.

5.3.2 The introduction of a junction in this location, where currently A5 north and A5 south traffic has priority and does not need to stop, will inevitably lead to increased journey times and delays for A5 traffic, but on the whole the modelling found that generated queues were of manageable length.

5.3.3 The option that performed best in Paramics was the staggered priority junction option, where ‘mainline’ traffic on the bypass does not incur any delays at the new junction. The next best performing option was the priority roundabout. It should be noted that both of these options were not modelled with the proposed stand-alone signalised pedestrian crossings in operation, which would be expected to increase queuing and delay, depending upon the pedestrian demand.

5.3.4 Both of the signalised junction options generated longer queues and longer journey times than the non-signalised options, as might be expected, particularly as these incorporate signalised pedestrian stages, which the other options do not. The benefits of the signalised options are that they provide safer, controlled access for traffic streams, and provide integrated facilities for pedestrians.


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6. ROAD SAFETY AUDIT

6.1 Introduction

6.1.1 SYSTRA commissioned Wylie Lodge Ltd, Independent Road Safety Consultants, to undertake a Stage 1 Road Safety Audit of Options 1, 2, 3 and 4.

6.1.2 The objective of a Road Safety Audit (RSA) is to identify any aspects of a road design or construction scheme that could give rise to road safety concerns and, where possible, to suggest modifications that would improve the road safety of the resultant scheme.

6.1.3 The Audit Team members were;

Audit Team Leader Blair Wyllie, I Eng, MCIHT, MSoRSA Audit Team Member David Lodge, BSc, MSc, CMILT, MCIHT, MSoRSA.

6.1.4 Both audit team members hold the Transport Scotland / Highways Agency Certificate of Competence.

6.1.5 The audit was carried out following the general principles and procedures set out in GG 119 of the Design Manual for Roads and Bridges (DMRB), with adaptions to meet the requirements of the highway authority (Overseeing Organisation), where required. The Road Safety Audit procedure is not an examination or verification of compliance to a design standard. Any notified departures from the design standard have been referenced within the report. The recommendations in this report are considered by the audit team to be appropriate and proportionate to the concerns and problems identified.

6.1.6 The following section summarises the main findings of the report. The full RSA Stage 1 report is included in Appendix D.

6.1.7 Where possible, the junction layout for each option has been updated in response to the comments raised in the audit. The tables in this section set out the points that have been raised, and how these have been addressed. A traffic light system has been adopted:

Green – either the comment is already addressed within the layout, or the layout has been updated to address the recommendation.

Amber – the comment should be investigated further at the detailed design stage. Red – It is not possible to address the comment


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6.1 General Recommendations

6.1.1 The RSA report made the general recommendations set out in Table 6.1.

Table 6.1 Road Safety Audit - General Recommendations

REF RECOMMENDATION SYSTRA COMMENT

5.1 Extend the 30mph speed limit on the link road to at least cover any new junctions, and the approaches to those junctions

Recommended that this is implemented as part of the scheme. This would be captured as part of the TRO process.

Recommended for consideration as part of detailed design.

5.2

Ensure that parking / waiting restrictions are in force to ensure that parking on A5 Station Road does not obstruct traffic flow near the level crossing (5.2). This would be captured as part of the TRO process

SYSTRA anticipated that parking would be removed as part of any upgrades. This would be captured as part of the TRO process.

Recommended for consideration as part of detailed design.

5.11 Need to ensure that refreshed yellow box markings and signing for the level crossing is included for all options

Layouts updated to reflect recommendation

5.12

Recommended that level crossing warning signs are in place on all approach arms, so that drivers are aware that there could be tailbacks from the crossing at the busiest times


Promote signalised crossings for pedestrians All pedestrian crossings shown on layouts are signalised

Investigate shared footways for pedestrians / cyclists.

SYSTRA have revisited the junction designs, and


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incorporated where appropriate.


6.2 Option 1

6.2.1 The RSA report made the observations and recommendations relating to Option 1 set out in Table 6.2.

Table 6.2 Road Safety Audit – Option 1 Observations / Recommendations


5.3

Pedestrian crossing on A5 west hidden from driver’s turning left from Balthane Road. Visibility obscured by third party fence

In response to the observation, the pedestrian crossing has been moved further to the west. The new location is compliant with guidance, but not now on a pedestrian desire line closer to the junction.

Layout updated to reflect recommendation

5.6 Recommendation that footway on west of Station Road is lowered and levelled.

This is what SYSTRA envisaged at this location.

Labelling updated to reflect recommendation

5.7

Recommended that pedestrian crossing on east arm (new link road) is moved as close to the roundabout as possible, to better tie in with pedestrian desire line.

The Traffic Signs Manual (2019) Para 15.8.9 states that the aim should be to lay at least the standard pattern of eight 2m marks on both sides of the crossing. Where site constraints prevent this, the length of the zig-zag marks may be varied to a minimum of 1 m and the number of marks reduced to a minimum of two (i.e. giving a total length of controlled area of between 2.75m and 4.5m)

The current design retains the full length of zig-zag markings, meaning that the crossings


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remain distant from the junction. These distances could be reduced if required.

5.8

Roundabouts are generally mode dangerous for pedestrians. Recommended that all pedestrian crossings are signalised.

All pedestrian crossings shown on layouts are signalised

5.9

Roundabouts are generally more dangerous for cyclists. Recommended that a shared 3m-wide footway is provided around the roundabout

SYSTRA has reviewed footway provision around the junction and added 3m shared footway / cycle lanes on the A5 north and Link Road approaches.


6 Roundabouts are a greater risk to cyclists

IoMG to note

6

Roundabouts make pedestrian routes less direct, and crossings around a roundabout require better judgement from pedestrians

IoMG to note

6.3 Option 2




5.4

A junction inter-visibility issue was identified at two locations, the left turn into Balthane Road, left turn out of Balthane Road (5.4). At both of these locations left-turning traffic will be unable to see a point behind the stopline they were turning towards

These have been flagged as departures from standards, and discussed with the Road Safety Auditor. Mitigation can be provided either by ensuring that the stage in which vehicles turn left does not follow the pedestrian stage, or increasing the intergreen stage to allow pedestrians extra time to clear


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crossings to which vehicles do not have full visibility.

SYSTRA recommend that the IoM Government note the mitigation options, and investigate whether additional land around the junction could be purchased to help reduce these Intervisibility issues.

5.6

Recommended that the footway on west of Station Road is lowered / widened to provide safe, level access to mobility impaired users).

This is what SYSTRA envisaged at this location.

Labelling updated to reflect recommendation

5.13

General comment relevant to all signalised junctions. Right-turning drivers who make a mistake will be at risk of a serious side-impact collision. Recommend that a right-turn filter arrow is provided

A filter arrow has been provided for traffic turning right into Balthane Road from the A5 south. It is proposed that the right-turn from the Link Road to the A5 north is banned, as less than 10 vehicles are predicted to make this movement in both the AM and PM peak hours.

Already incorporated into designs

6

General comment relevant to all signalised junctions. Safer provision for pedestrians and cyclists can be made at signalised junctions compared to roundabouts. Advanced stop lines and/or shared footway provision would improve safety for cyclists

Advanced stoplines could be incorporated into the junction layout if required. Shared footways have been provided alongside the Link Road and A5 north arms of the junction.


The RSA notes that this option is considered to be the safest of the options assessed.

6.4 Option 3



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5.5

General comment - Two junctions (compared to one) will create more turning movements, and therefore are not as safe as a single junction

IoMG to note

5.10

Recommended that a controlled pedestrian crossing point is provided across new link road

Signalized pedestrian crossing provided to east of realigned A5 north link.


6 Straight alignment of new link will encourage speeding

Recommended that this is addressed at detailed design through consideration of signage, surface material, perceived narrowing, gateway features or similar.

Recommended as part of detailed design.

6 General comment – Right-turning drivers who make a mistake will be at risk of a serious side-impact collision

There is no particular measures that can eliminate this risk. Setting a 30mph speed limit, incorporating warning signs and safety markings / surfacing can help to reduce this risk.

Not able to be wholly addressed

6.5 Option 4




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5.5

General comment - Two junctions (compared to one) will create more turning movements, and therefore are not as safe as a single junction

IoMG to note

5.10

Recommended that a controlled pedestrian crossing point is provided across new link road

Signalized pedestrian crossing provided to east of realigned A5 north link.


6 Straight alignment of new link will encourage speeding

Recommended that this is addressed at detailed design through consideration of signage, surface material, perceived narrowing, gateway features or similar.

Recommended as part of detailed design.

6 General comment – Right-turning drivers who make a mistake will be at risk of a serious side-impact collision

Right-turn lane and filter arrow provided into Balthane Road. No filter arrow has been assumed for the turn from the new link road into the realigned A5. This could be incorporated as an ‘on-demand’ stage, as the predicted number of right-turning vehicles is very low.



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7. SUMMARY AND CONCLUSION

7.1 Summary

7.1.1 Table 7.1 provides a summary of the options that have been considered.

REF DESCRIPTION JUNCTION

MODELLING

HIGHEST

RFC / DOS GENERAL COMMENTS

PARAMICS MODELLING INDICATIVE COST

WITHOUT OPTIMISM

BIAS

(INCLUDING 44%

OPTIMISM BIAS)

ROAD SAFETY DEPARTURES FROM

STANDARDS

WITHIN RELAXATIONS

(OUTSIDE MINIMUM)

1 Four-arm

roundabout

0.76

A5 south in

AM peak

hour


+ Makes good use of existing carriageway + Minimises disruption to properties to east

of A5

- Small amount of land take likely required to west of A5 in raised area with mature trees

- Roundabouts cannot incorporate pedestrian / cycle facilities

- Potentially challenging to produce compliant design in this location

3rd highest overall level of queuing at new junction

AM Peak max queues:

A5N – 100m Bypass – 50m

Balthane Road – 12m A5S – 24m

PM Peak max queues:



£757,000

(£1,090,000)

Roundabouts are generally less safe for

drivers, cyclists and pedestrians than

signalised junctions

Signalized pedestrian crossings have to be

set back from the roundabout, and are not

on favoured pedestrian desire lines.

Shared 3m footway / cycleways have been

provided where possible to cater for cyclists

5 (3)

2 Four-arm

signalised

junction

85.13

A5 north in

AM peak

hour


+ Makes good use of existing carriageway + Minimises disruption to properties to east

of A5 + Potential to provide priority to bypass

traffic within signal staging + Allows incorporation of signalised

pedestrian crossings, and advanced stop lines for cyclists.

- Potentially challenging to produce compliant design in this location

Highest overall levels of queuing at new junction

AM Peak max queues:



PM Peak max queues:



£755,000

(£1,088,000)

Considered the safest junction option

overall.

Incorporates signalized pedestrian

crossings, and could incorporate advanced

stop lines for cyclists if required.

Right-turn filter arrow provided to reduce

risk of side-impact collisions.

Junction inter-visibility issues have been

identified. These can be mitigated through

signal staging design, but recommended

that IoM Government investigate whether

2 (1)

3 Assumes 140s double-cycle, with pedestrians called once every 140s cycle.


Final 13/08/2020 /60


MODELLING

HIGHEST



WITHOUT OPTIMISM

BIAS

(INCLUDING 44%

OPTIMISM BIAS)


STANDARDS

WITHIN RELAXATIONS

(OUTSIDE MINIMUM)

land could be purchased to help eliminate

these issues.

3 Offset priority

junctions, with

one-way link

between

Balthane Road

and old A5

0.384

Balthane

Road in

AM peak

hour

+ Efficient alignment for bypass traffic + Best priority for bypass traffic of all the

options

- Does not allow incorporation of signalised pedestrian crossings, and advanced stop

lines for cyclists. - Priority junctions not as safe for traffic

turning into, or emerging from minor arms.

Lowest overall levels of queuing at new junction

AM Peak max queues:



PM Peak max queues:



£1,060,000

(£1,526,000)

Two junction configuration will create more

turning movements, and therefore overall

less safe than one junction.

Independent signalized pedestrian

crossings provided. Shared 3m footway /

cycleways have been provided where

possible to cater for cyclists.

Vehicular turning movements into and out

of side roads are not controlled. So not as

safe as signalised option.

Straight alignment of new Link Road could

encourage higher vehicles speeds - traffic

calming recommended.

1

4 Offset signalised

junctions, with

one-way link

between

Balthane Road

and old A5

78.45

A5 south in

AM peak

hour

+ Efficient alignment for bypass traffic + Potential to provide priority to bypass

traffic within signal staging + Allows incorporation of signalised

pedestrian crossings, and advanced stop lines for cyclists.

- Need to provide sufficient space between

signalised junctions to allow efficient

operation

2nd highest overall level of queuing at new junction

AM Peak max queues:



PM Peak max queues:

A5N –55 m Bypass – 105m

Balthane Road – 95 m A5S –170 m

£1,114,000

(£1,604,000)

Two junction configuration will create more

turning movements, and therefore overall

less safe than one junction.

Incorporates signalized pedestrian

crossings, and could incorporate advanced

stop lines for cyclists if required.

Right-turn filter arrow provided at Balthane

Road to reduce risk of side-impact

collisions. Right turn arrow for movements

into A5 north could be incorporated if

required.

2 (1)

4 Does not allow for delays caused by pedestrian crossings. 5 Assumes 120s single cycle, with pedestrians called every cycle.


Final 13/08/2020 /60


MODELLING

HIGHEST



WITHOUT OPTIMISM

BIAS

(INCLUDING 44%

OPTIMISM BIAS)


STANDARDS

WITHIN RELAXATIONS

(OUTSIDE MINIMUM)

Straight alignment of new Link Road could

encourage higher vehicles speeds - traffic

calming recommended.


Final 13/08/2020 /60

7.2 Conclusions

7.2.1 The option identification, sifting and design process has identified four main potential junction options.

7.2.2 Option 1, the four-arm roundabout, offers reasonable junction performance, but is not considered as safe in terms of vehicle, pedestrian, and particularly cycle, movements. Construction of this option would require 5 departures from standards, 3 of which would be outside of permitted relaxations, demonstrating that construction of a fully-compliant four-arm roundabout in this location is not possible.

7.2.3 The best-performing junction in terms of safety is Option 2, the single signalised junction. This would provide controlled vehicular access to and from major and minor arms, and also allow the incorporation of signalised pedestrian crossings within the junction itself, as well as allowing the option of advanced cycle stoplines on each approach. The non-signalised junction options do allow for signalised pedestrian crossings, but these would not be as closely aligned with pedestrian desire lines, and would operate independently of each junction.

7.2.4 Construction of Option 2 would require 3 departures from standards, 2 of which would be outside of permitted relaxations. This relates to inter-visibility when turning into Balthane Road from the new Link Road. Further discussions with the Road Safety Audit team suggest that these can be mitigated through signal staging design, or extension of inter-greens between particular movements.

7.2.5 In terms of predicted cost, Options 1 and 2 have a similar estimated cost, which is approximately 70% that of Options 3 and 4, the staggered junction options.

7.2.6 Option 3 performed best in terms of delays to mainline Link Road to A5 south traffic movements, but is a weaker option in terms of pedestrian, cycle and vehicle safety, with uncontrolled vehicle movements to and from the minor arms.

7.2.7 Option 4 performed better than Option 2 in terms of providing additional traffic capacity ‘headroom’ beyond 2028. A consideration is whether this additional traffic capacity is justified for the additional cost of Option 4 compared to Option 2. Option 4 would also incorporate signalised pedestrian facilities within the junction, as well as allowing for advanced cycle stop lines if required.

7.2.8 The Road Safety Audit also noted that two junctions, rather than one, could create more turning movements, and therefore Option 4 is inherently slightly more dangerous than Option 2.

7.2.9 On balance, SYSTRA considers that both signalised options merit further consideration. Recommended next steps are:

Internal discussions within the IoM Engineering team / Road Safety team to discuss the acceptability of potential departures from standards, or relaxations of standards.

Production of more detailed junction designs, potentially based upon topographic and utility surveys. These would allow cost-estimates to be further refined.


Final 13/08/2020 /60

APPENDIX A – Junction Layout Drawings

Refresh yellow box markings and signing at level crossing

Notes:

1. Do not scale from drawing2. All dimension in metres

Scale

Title

Project

Client

© This drawing is the property of SYSTRA Limited.The information should only be reproduced with

prior permission.

unless otherwise stated

ApprovedChecked

Date

Drawn

Option 1: Proposed Layout &Dimensions

Ballasalla Link Road Junction

-

Original drg. size

Drawing Status Drawing Number Rev.

A3L

FINAL

AMS

03/06/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text

Kerbside parking removed

AutoCAD SHX Text

3m wide shared footway / cycleway

AutoCAD SHX Text


AutoCAD SHX Text

'Toucan' Style Pedestrian Crossing

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text

Improved, levelled footway / cycleway


Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn

Option 2: Junction Layout andDimensions


-

Original drg. size


A3L

FINAL

AMS

11/08/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text

Right turn from bypass to A5 north prohibited

Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn

Option 2: Junction IntervisibilityZone & Conflicts


-

Original drg. size


A3L

FINAL

AMS

13/08/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

JunctionIntervisibility Zone

Conflict Areas ofJunctionIntervisibility Zone


Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn

Option 3: Priority JunctionsLayout


-

Original drg. size


A3L

FINAL

AMS

08/06/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text



Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn

Option 4: Signalised JunctionsLayout


-

Original drg. size


A3L

FINAL

AMS

11/08/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text

Signalised pedestrian crossings

AutoCAD SHX Text



Final 13/08/2020 Page 57/60

APPENDIX B – Junction Model Reports

Filename: Option 1_Single Roundabout.arc8 Path: \\edinfile\Edinburgh\Proposals\TI_Proposals\In preparation\Edin Dev Small Projects\Ballasalla Junction Improvement\Traffic Flows and Modelling\Option 1_Single Roundabout Report generation date: 8/10/2020 4:56:31 PM

» (Default Analysis Set) - Future Year + Bypass, AM » (Default Analysis Set) - Future Year + Bypass, PM

Summary of junction performance

Values shown are the maximum values over all time segments. Delay is the maximum value of average delay per arriving vehicle.

"D1 - Future Year + Bypass, AM " model duration: 8:00 AM - 9:30 AM

"D2 - Future Year + Bypass, PM" model duration: 8:00 AM - 9:30 AM

Run using Junctions 8.0.6.541 at 8/10/2020 4:56:30 PM

File summary

Analysis Options

Junctions 8ARCADY 8 - Roundabout Module

Version: 8.0.6.541 [19821,26/11/2015]

© Copyright TRL Limited, 2020

For sales and distribution information, program advice and maintenance, contact TRL:

Tel: +44 (0)1344 770758 email: [email protected] Web: http://www.trlsoftware.co.uk

The users of this computer program for the solution of an engineering problem are in no way relieved of their responsibility for the correctness of the solution

AM

Queue (PCU) Delay (s) RFC LOS

A1 - Future Year + Bypass

Arm A 0.69 9.65 0.41 A

Arm B 1.36 9.39 0.58 A

Arm C 0.23 6.37 0.19 A

Arm D 2.98 10.76 0.76 B

Title (untitled)

Location

Site Number

Date 4/28/2020

Version

Status (new file)

Identifier

Client

Jobnumber

Enumerator aspence1

Description

Vehicle Length (m)

Do Queue Variations

Calculate Residual Capacity

Residual Capacity Criteria Type

RFC Threshold

Average Delay Threshold (s)

Queue Threshold (PCU)

5.75 N/A 0.85 36.00 20.00

Generated on 8/10/2020 4:56:34 PM using Junctions 8 (8.0.6.541)

1

mailto:[email protected]

http://www.trlsoftware.co.uk/

Units

(Default Analysis Set) - Future Year + Bypass, AM

Data Errors and Warnings No errors or warnings

Analysis Set Details

Demand Set Details

Junction Network

Junctions

Junction Network Options

Arms

Arms

Capacity Options

Distance Units Speed Units Traffic Units Input Traffic Units Results Flow Units Average Delay Units Total Delay Units Rate Of Delay Units

m kph PCU PCU perHour s -Min perMin

Name Roundabout Capacity Model Description Locked Network Flow Scaling Factor (%) Reason For Scaling Factors

(Default Analysis Set) ARCADY 100.000

NameScenario

Name

Time Period Name

DescriptionTraffic Profile Type

Model Start Time (HH:mm)

Model Finish Time (HH:mm)

Model Time Period Length

(min)

Time Segment Length (min)

Single Time Segment Only

Locked

Future Year +

Bypass, AM

Future Year

+ BypassAM

ONE

HOUR08:00 09:30 90 15

Junction Name Junction Type Arm Order Grade Separated Large Roundabout Junction Delay (s) Junction LOS

1 (untitled) Roundabout A,B,C,D 9.93 A

Driving Side Lighting

Left Normal/unknown

Arm Arm Name Description

A A A5 North

B B Ballasalla Bypass

C C Balthane Road

D D A5 South

Arm Minimum Capacity (PCU/hr) Maximum Capacity (PCU/hr)

A 0.00 99999.00

B 0.00 99999.00

C 0.00 99999.00

D 0.00 99999.00


2

Roundabout Geometry

Pedestrian Crossings

Pelican/ Puffin Crossings

Slope / Intercept / Capacity

Roundabout Slope and Intercept used in model

The slope and intercept shown above include any corrections and adjustments.

Traffic Flows

Demand Set Data Options

ArmV - Approach road half-

width (m)E - Entry width

(m)l' - Effective flare

length (m)R - Entry radius

(m)D - Inscribed circle

diameter (m)PHI - Conflict (entry)

angle (deg)Exit Only

A 3.60 5.74 3.25 10.00 30.00 55.00

B 3.65 5.89 2.40 20.00 30.00 50.00

C 3.70 4.00 2.50 16.85 30.00 50.00

D 4.20 5.75 5.00 20.00 30.00 48.50

Arm Crossing Type

A Pelican

B Pelican

C Pelican

D Pelican

ArmAmber time

preceding red (s)

Amber time regarded as green

(s)

Time from traffic red start to green man start

(s)

Time period green man shown (s)

Clearance Period (s)

Traffic minimum green (s)

Space between crossing and junction entry (PCU)

A 3.00 2.90 1.00 6.00 6.00 7.00 5.00

B 3.00 2.90 1.00 6.00 6.00 7.00 4.00

C 3.00 2.90 1.00 6.00 6.00 7.00 5.00

D 3.00 2.90 1.00 6.00 6.00 7.00 7.00

Arm Enter slope and intercept directly Entered slope Entered intercept (PCU/hr) Final Slope Final Intercept (PCU/hr)

A (calculated) (calculated) 0.498 1123.215

B (calculated) (calculated) 0.532 1187.629

C (calculated) (calculated) 0.509 1093.568

D (calculated) (calculated) 0.579 1411.538

Default Vehicle

Mix

Vehicle Mix Varies Over Time

Vehicle Mix Varies Over Turn

Vehicle Mix Varies Over Entry

Vehicle Mix Source

PCU Factor

for a HV (PCU)

Default Turning

Proportions

Estimate from

entry/exit counts

Turning Proportions

Vary Over Time

Turning Proportions

Vary Over Turn

Turning Proportions

Vary Over Entry

ü üHV

Percentages2.00 ü ü


3

Entry Flows

General Flows Data

Pedestrian Flows

General Flows Data

Turning Proportions

Turning Counts / Proportions (PCU/hr) - Junction 1 (for whole period)

Turning Proportions (PCU) - Junction 1 (for whole period)

Vehicle Mix

Average PCU Per Vehicle - Junction 1 (for whole period)

Arm Profile Type Use Turning Counts Average Demand Flow (PCU/hr) Flow Scaling Factor (%)

A ONE HOUR ü 235.00 100.000

B ONE HOUR ü 479.00 100.000

C ONE HOUR ü 120.60 100.000

D ONE HOUR ü 918.90 100.000

Arm Profile Type Average Pedestrian Flow (Ped/hr)

A ONE HOUR 60.00

B ONE HOUR 60.00

C ONE HOUR 60.00

D ONE HOUR 60.00

To

From

A B C D

A 0.000 4.000 53.000 178.000

B 11.000 0.000 108.000 360.000

C 13.000 52.000 0.000 55.600

D 150.000 599.000 166.900 3.000

To

From

A B C D

A 0.00 0.02 0.23 0.76

B 0.02 0.00 0.23 0.75

C 0.11 0.43 0.00 0.46

D 0.16 0.65 0.18 0.00

To

From

A B C D

A 1.000 1.000 1.000 1.000

B 1.000 1.000 1.000 1.000

C 1.000 1.000 1.000 1.040

D 1.000 1.000 1.020 1.000


4

Heavy Vehicle Percentages - Junction 1 (for whole period)

Results

Results Summary for whole modelled period

Main Results for each time segment

Main results: (08:00-08:15)



To

From

A B C D

A 0.0 0.0 0.0 0.0

B 0.0 0.0 0.0 0.0

C 0.0 0.0 0.0 4.0

D 0.0 0.0 2.0 0.0

Arm Max RFC Max Delay (s) Max Queue (PCU) Max LOS

A 0.41 9.65 0.69 A

B 0.58 9.39 1.36 A

C 0.19 6.37 0.23 A

D 0.76 10.76 2.98 B

ArmTotal Demand

(PCU/hr)Entry Flow (PCU/hr)

Circulating Flow (PCU/hr)

Pedestrian Demand (Ped/hr)

Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 176.92 175.71 613.97 45.17 757.58 0.234 0.30 6.174 A

B 360.62 358.22 299.79 45.17 957.16 0.377 0.60 5.986 A

C 90.79 90.29 412.79 45.17 814.50 0.111 0.13 5.057 A

D 691.80 687.22 56.89 45.17 1290.04 0.536 1.14 5.948 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 211.26 210.77 736.10 53.94 702.09 0.301 0.43 7.319 A

B 430.61 429.64 359.52 53.94 935.63 0.460 0.84 7.103 A

C 108.42 108.26 495.10 53.94 768.62 0.141 0.17 5.548 A

D 826.07 823.91 68.22 53.94 1307.77 0.632 1.68 7.431 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 258.74 257.70 899.38 66.06 629.81 0.411 0.69 9.648 A

B 527.39 525.32 439.42 66.06 906.73 0.582 1.36 9.387 A

C 132.78 132.51 605.36 66.06 707.72 0.188 0.23 6.368 A

D 1011.73 1006.55 83.49 66.06 1337.16 0.757 2.98 10.756 B


5




(Default Analysis Set) - Future Year + Bypass, PM

Data Errors and Warnings No errors or warnings

Analysis Set Details

Demand Set Details

Junction Network

Junctions

Junction Network Options

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 258.74 258.74 903.95 66.06 634.89 0.408 0.69 9.570 A

B 527.39 527.40 441.42 66.06 919.78 0.573 1.35 9.176 A

C 132.78 132.78 607.77 66.06 708.48 0.187 0.23 6.365 A

D 1011.73 1011.88 83.68 66.06 1363.09 0.742 2.94 10.303 B

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 211.26 212.28 742.51 53.94 708.16 0.298 0.43 7.276 A

B 430.61 432.67 362.38 53.94 951.63 0.453 0.84 6.963 A

C 108.42 108.68 498.63 53.94 769.52 0.141 0.17 5.549 A

D 826.07 831.36 68.51 53.94 1347.66 0.613 1.62 7.066 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 176.92 177.42 619.77 45.17 763.51 0.232 0.30 6.147 A

B 360.62 361.59 302.68 45.17 972.32 0.371 0.60 5.903 A

C 90.79 90.95 416.71 45.17 816.03 0.111 0.13 5.055 A

D 691.80 693.81 57.33 45.17 1321.42 0.524 1.12 5.776 A

Name Roundabout Capacity Model Description Locked Network Flow Scaling Factor (%) Reason For Scaling Factors

(Default Analysis Set) ARCADY 100.000

NameScenario

Name

Time Period Name

DescriptionTraffic Profile Type

Model Start Time (HH:mm)

Model Finish Time (HH:mm)

Model Time Period Length

(min)

Time Segment Length (min)

Single Time Segment Only

Locked

Future Year +

Bypass, PM

Future Year

+ BypassPM

ONE

HOUR08:00 09:30 90 15

Junction Name Junction Type Arm Order Grade Separated Large Roundabout Junction Delay (s) Junction LOS

1 (untitled) Roundabout A,B,C,D 6.19 A

Driving Side Lighting

Left Normal/unknown


6

Arms

Arms

Capacity Options

Roundabout Geometry

Pedestrian Crossings

Pelican/ Puffin Crossings

Slope / Intercept / Capacity

Roundabout Slope and Intercept used in model

The slope and intercept shown above include any corrections and adjustments.

Arm Arm Name Description

A A A5 North

B B Ballasalla Bypass

C C Balthane Road

D D A5 South

Arm Minimum Capacity (PCU/hr) Maximum Capacity (PCU/hr)

A 0.00 99999.00

B 0.00 99999.00

C 0.00 99999.00

D 0.00 99999.00

ArmV - Approach road half-

width (m)E - Entry width

(m)l' - Effective flare

length (m)R - Entry radius

(m)D - Inscribed circle

diameter (m)PHI - Conflict (entry)

angle (deg)Exit Only

A 3.60 5.74 3.25 10.00 30.00 55.00

B 3.65 5.89 2.40 20.00 30.00 50.00

C 3.70 4.00 2.50 16.85 30.00 50.00

D 4.20 5.75 5.00 20.00 30.00 48.50

Arm Crossing Type

A Pelican

B Pelican

C Pelican

D Pelican

ArmAmber time

preceding red (s)

Amber time regarded as green

(s)

Time from traffic red start to green man start

(s)

Time period green man shown (s)

Clearance Period (s)

Traffic minimum green (s)

Space between crossing and junction entry (PCU)

A 3.00 2.90 1.00 6.00 6.00 7.00 5.00

B 3.00 2.90 1.00 6.00 6.00 7.00 4.00

C 3.00 2.90 1.00 6.00 6.00 7.00 5.00

D 3.00 2.90 1.00 6.00 6.00 7.00 7.00

Arm Enter slope and intercept directly Entered slope Entered intercept (PCU/hr) Final Slope Final Intercept (PCU/hr)

A (calculated) (calculated) 0.498 1123.215

B (calculated) (calculated) 0.532 1187.629

C (calculated) (calculated) 0.509 1093.568

D (calculated) (calculated) 0.579 1411.538


7

Traffic Flows

Demand Set Data Options

Entry Flows

General Flows Data

Pedestrian Flows

General Flows Data

Turning Proportions

Turning Counts / Proportions (PCU/hr) - Junction 1 (for whole period)

Turning Proportions (PCU) - Junction 1 (for whole period)

Default Vehicle

Mix

Vehicle Mix Varies Over Time

Vehicle Mix Varies Over Turn

Vehicle Mix Varies Over Entry

Vehicle Mix Source

PCU Factor

for a HV (PCU)

Default Turning

Proportions

Estimate from

entry/exit counts

Turning Proportions

Vary Over Time

Turning Proportions

Vary Over Turn

Turning Proportions

Vary Over Entry

ü üHV

Percentages2.00 ü ü

Arm Profile Type Use Turning Counts Average Demand Flow (PCU/hr) Flow Scaling Factor (%)

A ONE HOUR ü 146.00 100.000

B ONE HOUR ü 449.00 100.000

C ONE HOUR ü 200.00 100.000

D ONE HOUR ü 490.00 100.000

Arm Profile Type Average Pedestrian Flow (Ped/hr)

A ONE HOUR 60.00

B ONE HOUR 60.00

C ONE HOUR 60.00

D ONE HOUR 60.00

To

From

A B C D

A 0.000 12.000 11.000 123.000

B 6.000 0.000 38.000 405.000

C 37.000 71.000 0.000 92.000

D 153.000 295.000 33.000 9.000

To

From

A B C D

A 0.00 0.08 0.08 0.84

B 0.01 0.00 0.08 0.90

C 0.19 0.36 0.00 0.46

D 0.31 0.60 0.07 0.02


8

Vehicle Mix

Average PCU Per Vehicle - Junction 1 (for whole period)

Heavy Vehicle Percentages - Junction 1 (for whole period)

Results

Results Summary for whole modelled period

Main Results for each time segment



To

From

A B C D

A 1.000 1.000 1.000 1.000

B 1.000 1.000 1.000 1.000

C 1.000 1.000 1.000 1.000

D 1.000 1.000 1.000 1.000

To

From

A B C D

A 0.0 0.0 0.0 0.0

B 0.0 0.0 0.0 0.0

C 0.0 0.0 0.0 0.0

D 0.0 0.0 0.0 0.0

Arm Max RFC Max Delay (s) Max Queue (PCU) Max LOS

A 0.20 5.54 0.25 A

B 0.49 7.00 0.95 A

C 0.31 7.18 0.44 A

D 0.44 5.24 0.78 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 109.92 109.36 305.72 45.17 895.42 0.123 0.14 4.577 A

B 338.03 336.11 131.85 45.17 1036.87 0.326 0.48 5.124 A

C 150.57 149.68 406.54 45.17 819.35 0.184 0.22 5.369 A

D 368.90 367.25 85.32 45.17 1260.37 0.293 0.41 4.023 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 131.25 131.09 366.32 53.94 859.33 0.153 0.18 4.942 A

B 403.64 402.99 158.03 53.94 1025.30 0.394 0.64 5.779 A

C 179.80 179.50 487.40 53.94 777.46 0.231 0.30 6.018 A

D 440.50 439.98 102.31 53.94 1246.58 0.353 0.54 4.460 A


9





ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 160.75 160.48 448.37 66.06 810.34 0.198 0.25 5.537 A

B 494.36 493.12 193.45 66.06 1006.26 0.491 0.95 6.998 A

C 220.20 219.66 596.48 66.06 720.85 0.305 0.43 7.175 A

D 539.50 538.55 125.20 66.06 1224.47 0.441 0.78 5.240 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 160.75 160.75 449.22 66.06 811.79 0.198 0.25 5.529 A

B 494.36 494.36 193.78 66.06 1014.54 0.487 0.95 6.922 A

C 220.20 220.20 597.85 66.06 723.98 0.304 0.44 7.145 A

D 539.50 539.50 125.51 66.06 1230.79 0.438 0.78 5.207 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 131.25 131.51 367.62 53.94 861.26 0.152 0.18 4.934 A

B 403.64 404.87 158.54 53.94 1036.00 0.390 0.64 5.716 A

C 179.80 180.33 489.51 53.94 781.46 0.230 0.30 5.995 A

D 440.50 441.44 102.79 53.94 1254.90 0.351 0.54 4.432 A

ArmTotal Demand




Capacity (PCU/hr)

RFCEnd Queue

(PCU)Delay

(s)LOS

A 109.92 110.08 307.64 45.17 898.15 0.122 0.14 4.570 A

B 338.03 338.69 132.70 45.17 1049.24 0.322 0.48 5.072 A

C 150.57 150.88 409.55 45.17 823.95 0.183 0.23 5.352 A

D 368.90 369.43 86.00 45.17 1270.82 0.290 0.41 3.997 A


10

Selected Data And Results Page 1

Selected Data And Results User and Project Details

Project: Ballasalla Junction Options

Title: Option 2 - Signalised crossroads

Location:

Client: IoM Government

Additional detail:

File name: Ballasalla_Option 2_for final report.lsg3x

Author: GM

Company: SYSTRA

Address:

Network Layout Diagram


Phase Diagram

Phase Input Data

Phase Name Phase Type Assoc. Phase Street Min Cont Min

A Traffic 7 7

B Traffic 7 7

C Traffic 7 7

D Traffic 7 7

E Ind. Arrow D 4 4

F Pedestrian 7 7

G Pedestrian 9 9

H Pedestrian 8 8

I Pedestrian 10 10

A

B

C

D

E

F

G

H

I


Phase Intergreens Matrix

Starting Phase

Terminating Phase

A B C D E F G H I

A - 5 - 5 5 5 9 10 10

B 5 - 6 - 5 9 5 8 9

C - 6 - 5 5 10 9 5 8

D 5 - 5 - - 10 10 9 5

E 5 5 5 - - - - 9 5

F 9 9 9 9 - - - - -

G 10 10 10 10 - - - - -

H 10 10 10 10 10 - - - -

I 11 11 11 11 11 - - - -

Phases in Stage

Stage No. Phases in Stage

1 A C

2 B D

3 D E

4 F G H I

Stage Diagram

Network Control Plans

Plan Controller Sequence Name Sequence

Single cycle C1 All stages 1,2,3,4

Double cycle C1 Double cycled 1,2,3,4,1,2,3

no peds C1 No peds 1,2,3

Phase Delays

Term. Stage Start Stage Phase Type Value Cont value

4 1 F Losing 2 2

4 1 G Losing 1 1

4 1 H Losing 1 1

A

B

C

D

E

F

G

H

I

1 Min >= 7A

B

C

D

E

F

G

H

I

2 Min >= 7A

B

C

D

E

F

G

H

I

3 Min >= 4A

B

C

D

E

F

G

H

I

4 Min >= 9


Lane Input Data

Junction: Ballasalla - Signalised Option 5

Lane Lane Type

Phases Start Disp.

End Disp.

Physical Length (PCU)

Sat Flow Type

Def User Saturation

Flow (PCU/Hr)

Lane Width

(m) Gradient

Nearside Lane

Turns Turning Radius

(m)

1/1 (A5 North)

O A 2 3 60.0 Geom - 4.00 0.00 Y

Arm 6 Left

10.00

Arm 7 Ahead

Inf

Arm 8 Right

20.00

2/1 (Bypass)

U B 2 3 60.0 Geom - 3.65 0.00 Y

Arm 7 Left

15.00

Arm 8 Ahead

Inf

3/1 (Balthane

Road) O C 2 3 60.0 Geom - 3.65 0.00 Y

Arm 5 Ahead

Inf

Arm 6 Right

15.00

Arm 8 Left

10.00

4/1 (A5 south)

U D 2 3 60.0 Geom - 3.65 0.00 Y

Arm 5 Left

50.00

Arm 6 Ahead

Inf

4/2 (A5 south)

O D E 2 3 3.0 Geom - 3.65 0.00 Y Arm 7 Right

15.00

5/1 (A5 south

(exit)) U 2 3 60.0 Inf - - - - - -

6/1 (Bypass (Exit))

U 2 3 60.0 Inf - - - - - -

7/1 (Balthan

Road (exit)) U 2 3 60.0 Inf - - - - - -

8/1 (A5 south

(exit)) U 2 3 60.0 Inf - - - - - -


Give-Way Lane Input Data

Junction: Ballasalla - Signalised Option 5

Lane Movement

Max Flow when

Giving Way (PCU/Hr)

Min Flow when

Giving Way (PCU/Hr)

Opposing Lane

Opp. Lane Coeff.

Opp. Mvmnts.

Right Turn Storage (PCU)

Non-Blocking Storage (PCU)

RTF Right Turn Move up (s)

Max Turns in Intergreen

(PCU)

1/1 (A5 North)

8/1 (Right) 1439 0 3/1 1.09 To 5/1 (Ahead) To 8/1 (Left) 2.00 2.00 0.50 2 2.00

3/1 (Balthane Road)

6/1 (Right) 1439 0 1/1 1.09 To 6/1 (Left) To 7/1 (Ahead) 2.00 2.00 0.50 2 2.00

4/2 (A5 south)

7/1 (Right) 1439 0 2/1 1.09 To 7/1 (Left) To 8/1 (Ahead) 3.00 - 0.50 3 2.00

Selected Data And Results Page 6 Scenario 1: 'Future Year + Bypass AM Peak' (FG1: 'Future Year + Bypass AM Peak', Plan 1: 'Single cycle')

Turning Counts Data

Ref Junction Arms Count Modelled Flow (*) Balancing Factor % Diff Diff GEH

J1:Ballasalla - Signalised Option 5 1 -> 6 - 4












Network Results

Item Lane Description

Lane Type

Controller Stream

Full Phase Arrow Phase

Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)

Max Sat Flow (pcu/Hr)

Capacity (pcu)

Deg Sat (%)

Network: Option 2 - Signalised crossroads

- - N/A - - - - - - - - - - 109.9%

Ballasalla - Signalised Option 5

- - N/A - - - - - - - - - - 109.9%

1/1 A5 North Left Ahead Right

O N/A A 1 11 11 22 - 235 1902 1902 214 109.9%

2/1 Bypass Left

Ahead U N/A B 1 32 28 60 - 468 1935 1935 709 66.0%

3/1 Balthane

Road Ahead Right Left

O N/A C 1 11 11 22 - 121 1780 1780 237 51.0%

4/1+4/2 A5 south Left Ahead Right

U+O N/A D E 1 43 27 70 5 916 1968:1800 1968 806+180 93.0 : 93.0%

5/1 A5 south

(exit) U N/A - - - - - - 163 Inf Inf Inf 0.0%

6/1 Bypass (Exit) U N/A - - - - - - 655 Inf Inf Inf 0.0%

7/1 Balthan Road


8/1 A5 south



Item Arriving (pcu)

Leaving (pcu)

Turners In Gaps (pcu)

Turners When Unopposed (pcu)

Turners In Intergreen (pcu)

Uniform Delay (pcuHr)

Rand + Oversat Delay (pcuHr)

Storage Area Uniform Delay (pcuHr)

Total Delay (pcuHr)

Av. Delay Per PCU (s/pcu)

Av. Uniform Stops Per PCU (stops/pcu)

Mean Max Queue (pcu)

Average Excess Queue (pcu)

Weighted Deg Sat (%)

Weighted Total Delay (pcuHr)


- - 303 27 51 13.1 21.8 0.5 35.4 - - - - 109.9% 38.9


- - 303 27 51 13.1 21.8 0.5 35.4 - - - - 109.9% 38.9

1/1 235 214 117 0 45 3.5 14.6 0.2 18.3 279.9 1.7 21.0 0.00 109.9% 19.0

2/1 468 468 - - - 3.1 1.0 - 4.1 31.2 0.8 10.7 0.00 66.0% 4.8

3/1 121 121 52 0 0 1.2 0.5 0.0 1.7 51.6 0.9 3.3 0.00 51.0% 1.9

4/1+4/2 916 916 134 27 6 5.3 5.7 0.3 11.3 44.5 1.1 26.1 0.00 93.0 : 93.0%

13.2

5/1 163 163 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 655 655 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 323 323 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 578 578 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

C1 PRC for Signalled Lanes (%): -22.1 Total Delay for Signalled Lanes (pcuHr): 35.38 Cycle Time (s): 90 PRC Over All Lanes (%): -22.1 Total Delay Over All Lanes(pcuHr): 35.38

Selected Data And Results Page 9 Scenario 2: 'Future Year + Bypass PM Peak' (FG2: 'Future Year + Bypass PM Peak', Plan 1: 'Single cycle')

Turning Counts Data














Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 83.0%


- - N/A - - - - - - - - - - 83.0%


O N/A A 1 14 11 25 - 146 1874 1874 176 83.0%

2/1 Bypass Left

Ahead U N/A B 1 29 31 60 - 443 1963 1963 654 67.7%

3/1 Balthane


O N/A C 1 14 11 25 - 200 1793 1793 299 66.9%


U+O N/A D E 1 40 30 70 5 481 1960:1800 1960 826+61 54.3 : 54.3%

5/1 A5 south



7/1 Balthan Road


8/1 A5 south



Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 199 3 25 8.9 4.8 0.3 14.0 - - - - 83.0% 16.2


- - 199 3 25 8.9 4.8 0.3 14.0 - - - - 83.0% 16.2

1/1 146 146 99 0 24 1.4 2.1 0.2 3.8 93.3 1.8 5.7 0.00 83.0% 4.3

2/1 443 443 - - - 3.2 1.0 - 4.2 34.3 0.9 10.5 0.00 67.7% 4.9

3/1 200 200 71 0 0 2.0 1.0 0.0 2.9 53.0 0.9 5.7 0.00 66.9% 3.3

4/1+4/2 481 481 29 3 1 2.4 0.6 0.1 3.0 22.7 0.8 9.1 0.00 54.3 : 54.3%

3.7

5/1 190 190 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 378 378 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 82 82 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 620 620 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

C1 PRC for Signalled Lanes (%): 8.5 Total Delay for Signalled Lanes (pcuHr): 13.97 Cycle Time (s): 90 PRC Over All Lanes (%): 8.5 Total Delay Over All Lanes(pcuHr): 13.97

Selected Data And Results Page 12 Scenario 3: 'Future Year + Bypass AM Peak' (FG1: 'Future Year + Bypass AM Peak', Plan 1: 'Single cycle')

Turning Counts Data














Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 106.6%


- - N/A - - - - - - - - - - 106.6%


O N/A A 1 13 11 24 - 235 1902 1902 220 106.6%

2/1 Bypass Left

Ahead U N/A B 1 40 30 70 - 468 1935 1935 793 59.0%

3/1 Balthane


O N/A C 1 13 11 24 - 121 1780 1780 249 48.6%


U+O N/A D E 1 51 29 80 5 916 1968:1800 1968 852+190 87.9 : 87.9%

5/1 A5 south



7/1 Balthan Road


8/1 A5 south



Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 327 13 46 13.0 16.8 0.5 30.3 - - - - 106.6% 33.7


- - 327 13 46 13.0 16.8 0.5 30.3 - - - - 106.6% 33.7

1/1 235 220 126 0 41 3.5 12.1 0.2 15.8 242.7 1.7 19.1 0.00 106.6% 16.6

2/1 468 468 - - - 3.0 0.7 - 3.7 28.5 0.8 10.7 0.00 59.0% 4.4

3/1 121 121 52 0 0 1.3 0.5 0.0 1.8 53.6 0.9 3.6 0.00 48.6% 2.0

4/1+4/2 916 916 149 13 5 5.2 3.5 0.3 9.0 35.3 1.0 24.9 0.00 87.9 : 87.9%

10.7

5/1 163 163 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 655 655 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 325 325 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 583 583 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

C1 PRC for Signalled Lanes (%): -18.5 Total Delay for Signalled Lanes (pcuHr): 30.34 Cycle Time (s): 100 PRC Over All Lanes (%): -18.5 Total Delay Over All Lanes(pcuHr): 30.34

Selected Data And Results Page 15 Scenario 4: 'Future Year + Bypass AM Peak Double cycle' (FG1: 'Future Year + Bypass AM Peak', Plan 2: 'Double cycle')

Turning Counts Data














Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 85.1%


- - N/A - - - - - - - - - - 85.1%


O N/A A 2 20 5(76) 17(84) - 235 1902 1902 276 85.1%

2/1 Bypass Left

Ahead U N/A B 2 55 23(90) 37(131) - 468 1935 1935 788 59.4%

3/1 Balthane


O N/A C 2 20 5(76) 17(84) - 121 1780 1780 280 43.3%


U+O N/A D E 2 75 22(89) 46(0) 8 916 1968:1800 1968 912+203 82.2 : 82.2%

5/1 A5 south



7/1 Balthan Road


8/1 A5 south



Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 335 26 36 8.5 5.9 0.4 14.8 - - - - 85.1% 18.1


- - 335 26 36 8.5 5.9 0.4 14.8 - - - - 85.1% 18.1

1/1 235 235 149 0 29 1.9 2.5 0.1 4.6 69.8 1.7 7.0 0.00 85.1% 5.3

2/1 468 468 - - - 2.2 0.7 - 3.0 22.9 0.8 9.6 0.00 59.4% 3.6

3/1 121 121 52 0 0 0.9 0.4 0.0 1.3 38.0 0.9 2.5 0.00 43.3% 1.5

4/1+4/2 916 916 133 26 7 3.5 2.3 0.3 6.0 23.6 1.0 20.9 0.00 82.2 : 82.2%

7.7

5/1 163 163 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 655 655 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 328 328 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 594 594 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0


Selected Data And Results Page 18 Scenario 5: 'Future Year + Bypass PM Peak Double cycle' (FG2: 'Future Year + Bypass PM Peak', Plan 2: 'Double cycle')

Turning Counts Data














Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 73.0%


- - N/A - - - - - - - - - - 73.0%


O N/A A 2 21 5(83) 18(91) - 146 1874 1874 200 73.0%

2/1 Bypass Left

Ahead U N/A B 2 51 24(97) 42(130) - 443 1963 1963 743 59.6%

3/1 Balthane


O N/A C 2 21 5(83) 18(91) - 200 1793 1793 295 67.9%


U+O N/A D E 2 73 23(96) 52(0) 10 481 1960:1800 1960 971+72 46.1 : 46.1%

5/1 A5 south



7/1 Balthan Road


8/1 A5 south



Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 181 4 43 6.4 3.5 0.3 10.2 - - - - 73.0% 12.2


- - 181 4 43 6.4 3.5 0.3 10.2 - - - - 73.0% 12.2

1/1 146 146 82 0 41 1.2 1.3 0.2 2.7 65.5 1.8 4.3 0.00 73.0% 3.1

2/1 443 443 - - - 2.3 0.7 - 3.0 24.4 0.8 9.2 0.00 59.6% 3.7

3/1 200 200 71 0 0 1.5 1.0 0.0 2.6 46.4 0.9 5.0 0.00 67.9% 2.9

4/1+4/2 481 481 28 4 1 1.5 0.4 0.1 2.0 14.6 0.7 7.8 0.00 46.1 : 46.1%

2.5

5/1 190 190 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 378 378 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 82 82 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 620 620 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0


Selected Data And Results Page 21 Scenario 6: 'Future Year + Bypass AM Peak no peds' (FG1: 'Future Year + Bypass AM Peak', Plan 3: 'no peds')

Turning Counts Data














Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 69.1%


- - N/A - - - - - - - - - - 69.1%


O N/A A 1 17 5 22 - 235 1902 1902 340 69.1%

2/1 Bypass Left

Ahead U N/A B 1 52 28 80 - 468 1935 1935 1140 41.1%

3/1 Balthane


O N/A C 1 17 5 22 - 121 1780 1780 356 34.0%


U+O N/A D E 1 63 27 0 5 916 1968:1800 1968 1157+258 64.7 : 64.7%

5/1 A5 south



7/1 Balthan Road


8/1 A5 south



Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 377 15 6 6.1 2.6 0.3 9.1 - - - - 69.1% 11.5


- - 377 15 6 6.1 2.6 0.3 9.1 - - - - 69.1% 11.5

1/1 235 235 178 0 0 2.2 1.1 0.2 3.4 52.6 1.7 6.5 0.00 69.1% 4.1

2/1 468 468 - - - 1.3 0.3 - 1.7 12.7 0.5 6.6 0.00 41.1% 2.1

3/1 121 121 52 0 0 1.0 0.3 0.0 1.3 38.6 0.9 2.8 0.00 34.0% 1.5

4/1+4/2 916 916 147 15 6 1.6 0.9 0.2 2.7 10.6 0.6 11.7 0.00 64.7 : 64.7%

3.8

5/1 163 163 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 655 655 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 328 328 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 594 594 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0


Selected Data And Results Page 24 Scenario 7: 'Future Year + Bypass PM Peak no peds' (FG2: 'Future Year + Bypass PM Peak', Plan 3: 'no peds')

Turning Counts Data














Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 42.3%


- - N/A - - - - - - - - - - 42.3%


O N/A A 1 23 5 28 - 146 1874 1874 347 42.1%

2/1 Bypass Left

Ahead U N/A B 1 47 34 81 - 443 1963 1963 1047 42.3%

3/1 Balthane


O N/A C 1 23 5 28 - 200 1793 1793 478 41.8%


U+O N/A D E 1 57 33 0 4 481 1960:1800 1960 1168+86 38.3 : 38.3%

5/1 A5 south



7/1 Balthan Road


8/1 A5 south



Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 223 3 1 5.2 1.4 0.2 6.8 - - - - 42.3% 8.4


- - 223 3 1 5.2 1.4 0.2 6.8 - - - - 42.3% 8.4

1/1 146 146 123 0 0 1.1 0.4 0.2 1.6 40.4 1.6 3.4 0.00 42.1% 2.1

2/1 443 443 - - - 1.6 0.4 - 1.9 15.6 0.6 7.0 0.00 42.3% 2.4

3/1 200 200 71 0 0 1.5 0.4 0.0 1.9 33.7 0.8 4.5 0.00 41.8% 2.2

4/1+4/2 481 481 29 3 1 1.0 0.3 0.0 1.3 10.1 0.5 5.7 0.00 38.3 : 38.3%

1.8

5/1 190 190 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 378 378 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 82 82 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 620 620 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0



Selected Data And Results User and Project Details

Project: Ballasalla Junction Options

Title: Option 4 - Linked signals

Location:

Client: IoM Government

Additional detail:

File name: Option 3 Double signals.lsg3x

Author: GM

Company: Systra

Address:

Network Layout Diagram


Phase Diagram

Phase Input Data

Phase Name Phase Type Stage Stream Assoc. Phase Street Min Cont Min

A Traffic 1 7 7

B Traffic 1 7 7

C Traffic 1 7 7

D Traffic 2 7 7

E Traffic 2 7 7

F Traffic 2 7 7

G Pedestrian 1 12 12

H Pedestrian 2 12 12

A

B

C

D

E

F

GH


Phase Intergreens Matrix

Starting Phase

Terminating Phase

A B C D E F G H

A - 5 5 - - - 10 -

B 5 - - - - - 11 -

C 5 - - - - - 10 -

D - - - - 5 - - 10

E - - - 5 - 5 - 10

F - - - - 5 - - 11

G 9 9 9 - - - - -

H - - - 9 9 9 - -

Phases in Stage

Stream Stage No. Phases in Stage

1 1 B C

1 2 A

1 3 G

2 1 D F

2 2 E

2 3 H

Stage Diagram Stage Stream: 1

Stage Stream: 2

Phase Delays Stage Stream: 1


There are no Phase Delays defined

Stage Stream: 2


There are no Phase Delays defined

A

B

CG

1 Min >= 7A

B

CG

2 Min >= 7A

B

CG

3 Min >= 12

D

E

F

H

1 Min >= 7

D

E

F

H

2 Min >= 7

D

E

F

H

3 Min >= 12


Lane Input Data

Junction: A5 Ballasalla

Lane Lane Type

Phases Start Disp.

End Disp.

Physical Length (PCU)

Sat Flow Type

Def User Saturation

Flow (PCU/Hr)

Lane Width

(m) Gradient

Nearside Lane

Turns Turning Radius

(m)

1/1 (A5 north)

U A 2 3 60.0 Geom - 3.65 0.00 Y

Arm 6 Left

15.00

Arm 10 Right

15.00

2/1 (Bypass)

U B 2 3 60.0 Geom - 3.65 0.00 Y Arm 10 Ahead

Inf

2/2 (Bypass)

O B 2 3 5.0 Geom - 3.65 0.00 Y Arm 5 Right

15.00

3/1 (Balthane

Road) U E 2 3 60.0 Geom - 3.65 0.00 Y

Arm 8 Left

15.00

Arm 9 Right

15.00

4/1 (A5 west)

U F 2 3 60.0 Geom - 3.65 0.00 Y Arm 9 Ahead

Inf

4/2 (A5 west)

O F 2 3 5.0 Geom - 3.65 0.00 Y Arm 7 Right

15.00

5/1 (A5 north

exit) U 2 3 60.0 Inf - - - - - -

6/1 (Bypass

exit) U 2 3 60.0 Inf - - - - - -

7/1 (Balthane Road exit)

U 2 3 60.0 Inf - - - - - -

8/1 (A5 west

exit) U 2 3 60.0 Inf - - - - - -

9/1 (Internal

EB) U C 2 3 10.4 Geom - 3.65 0.00 Y

Arm 5 Left

15.00

Arm 6 Ahead

Inf

10/1 (Internal

WB) U D 2 3 10.4 Geom - 3.65 0.00 Y

Arm 7 Left

15.00

Arm 8 Ahead

Inf


Give-Way Lane Input Data

Junction: A5 Ballasalla

Lane Movement

Max Flow when

Giving Way (PCU/Hr)

Min Flow when

Giving Way (PCU/Hr)

Opposing Lane

Opp. Lane Coeff.

Opp. Mvmnts.

Right Turn Storage (PCU)

Non-Blocking Storage (PCU)

RTF Right Turn Move up (s)

Max Turns in Intergreen

(PCU)

2/2 (Bypass)

5/1 (Right) 1439 0 9/1 1.09 To 6/1 (Ahead) 2.00 - 0.50 2 2.00

4/2 (A5 west)

7/1 (Right) 1439 0 10/1 1.09 To 8/1 (Ahead) 2.00 - 0.50 2 2.00

Selected Data And Results Page 6 Scenario 1: 'AM with peds' (FG1: 'AM peak hour', Plan 1: 'Single cycle with peds')

Turning Counts Data


J1:A5 Ballasalla 1 -> 6 - 4













Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)

Network: Option 4 - Linked signals

- - N/A - - - - - - - - - - 78.4%

A5 Ballasalla

- - N/A - - - - - - - - - - 78.4%

1/1 A5 north Left

Right U 1 A 1 19 79 98 - 228 1800 1800 300 76.0%

2/1+2/2 Bypass Right

Ahead U+O 1 B 1 65 9 74 - 464 1980:1800 1980 1066+26

42.5 : 42.5%

3/1 Balthane Road Left

Right U 2 E 1 10 102 112 - 122 1800 1800 165 73.9%

4/1+4/2 A5 west

Right Ahead U+O 2 F 1 74 23 97 - 937 1980:1800 1980 1029+223

74.8 : 74.8%

5/1 A5 north exit U N/A - - - - - - 189 Inf Inf Inf 0.0%

6/1 Bypass exit U N/A - - - - - - 662 Inf Inf Inf 0.0%

7/1 Balthane Road exit

U N/A - - - - - - 327 Inf Inf Inf 0.0%

8/1 A5 west exit U N/A - - - - - - 573 Inf Inf Inf 0.0%

9/1 Internal EB Left Ahead

U 1 C 1 65 9 74 - 836 1939 1939 1066 78.4%

10/1 Internal WB Left Ahead

U 2 D 1 74 23 97 - 677 1934 1934 1209 56.0%


Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 165 0 13 14.7 7.1 0.4 22.2 - - - - 78.4% 26.1

A5 Ballasalla

- - 165 0 13 14.7 7.1 0.4 22.2 - - - - 78.4% 26.1

1/1 228 228 - - - 3.0 1.5 - 4.5 71.7 1.0 8.7 0.00 76.0% 4.9

2/1+2/2 464 464 11 0 0 2.0 0.4 0.0 2.4 18.7 0.7 9.3 0.00 42.5 : 42.5%

3.0

3/1 122 122 - - - 1.8 1.3 - 3.1 92.5 1.0 5.3 0.00 73.9% 3.4

4/1+4/2 937 937 154 0 13 3.9 1.5 0.4 5.7 21.9 0.8 21.7 0.00 74.8 : 74.8%

7.1

5/1 189 189 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 662 662 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 327 327 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 573 573 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

9/1 836 836 - - - 2.9 1.8 - 4.6 20.0 0.4 10.1 0.00 78.4% 5.2

10/1 677 677 - - - 1.2 0.6 - 1.8 9.5 0.5 12.0 0.00 56.0% 2.4

C1 Stream: 1 PRC for Signalled Lanes (%): 14.8 Total Delay for Signalled Lanes (pcuHr): 11.61 Cycle Time (s): 120 C1 Stream: 2 PRC for Signalled Lanes (%): 20.3 Total Delay for Signalled Lanes (pcuHr): 10.63 Cycle Time (s): 120 PRC Over All Lanes (%): 14.8 Total Delay Over All Lanes(pcuHr): 22.23

Selected Data And Results Page 9 Scenario 2: 'PM with peds' (FG2: 'PM peak hour', Plan 1: 'Single cycle with peds')

Turning Counts Data















Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 57.7%

A5 Ballasalla

- - N/A - - - - - - - - - - 57.7%

1/1 A5 north Left

Right U 1 A 1 22 76 98 - 148 1800 1800 345 42.9%


Ahead U+O 1 B 1 62 9 71 - 455 1980:1800 1980 1028+14

43.7 : 43.7%


Right U 2 E 1 23 94 117 - 201 1800 1800 360 55.8%

4/1+4/2 A5 west

Right Ahead U+O 2 F 1 61 28 89 - 484 1980:1800 1980 959+70

47.0 : 47.0%




U N/A - - - - - - 88 Inf Inf Inf 0.0%



U 1 C 1 62 9 71 - 560 1914 1914 1005 55.7%


U 2 D 1 61 28 89 - 585 1962 1962 1014 57.7%


Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 39 0 0 12.6 3.1 0.1 15.9 - - - - 57.7% 19.1

A5 Ballasalla

- - 39 0 0 12.6 3.1 0.1 15.9 - - - - 57.7% 19.1

1/1 148 148 - - - 1.8 0.4 - 2.1 51.8 0.9 4.7 0.00 42.9% 2.4

2/1+2/2 455 455 6 0 0 2.2 0.4 0.0 2.6 20.6 0.8 9.5 0.00 43.7 : 43.7%

3.3

3/1 201 201 - - - 2.4 0.6 - 3.0 54.5 0.9 6.7 0.00 55.8% 3.4

4/1+4/2 484 484 33 0 0 2.4 0.4 0.1 3.0 22.2 0.7 10.2 0.00 47.0 : 47.0%

3.6

5/1 198 198 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 380 380 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 88 88 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 622 622 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

9/1 560 560 - - - 2.1 0.6 - 2.8 17.7 0.6 7.2 0.00 55.7% 3.4

10/1 585 585 - - - 1.7 0.7 - 2.4 14.6 0.6 13.1 0.00 57.7% 3.1


Selected Data And Results Page 12 Scenario 3: 'AM no peds' (FG1: 'AM peak hour', Plan 2: 'No peds')

Turning Counts Data















Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 60.7%

A5 Ballasalla

- - N/A - - - - - - - - - - 60.7%

1/1 A5 north Left

Right U 1 A 1 20 80 0 - 228 1800 1800 378 60.3%


Ahead U+O 1 B 1 70 5 75 - 464 1980:1800 1980 1376+33

32.9 : 32.9%


Right U 2 E 1 11 32 43 - 122 1800 1800 216 56.5%

4/1+4/2 A5 west

Right Ahead U+O 2 F 1 79 48 27 - 937 1980:1800 1980 1315+285

58.6 : 58.6%




U N/A - - - - - - 327 Inf Inf Inf 0.0%



U 1 C 1 70 5 75 - 836 1939 1939 1377 60.7%


U 2 D 1 79 48 27 - 677 1934 1934 1547 43.8%


Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 178 0 0 7.0 3.5 0.1 10.7 - - - - 60.7% 13.3

A5 Ballasalla

- - 178 0 0 7.0 3.5 0.1 10.7 - - - - 60.7% 13.3

1/1 228 228 - - - 2.3 0.8 - 3.0 47.6 0.9 6.5 0.00 60.3% 3.4

2/1+2/2 464 464 11 0 0 0.7 0.2 0.0 1.0 7.5 0.4 4.9 0.00 32.9 : 32.9%

1.3

3/1 122 122 - - - 1.4 0.6 - 2.0 60.4 0.9 3.8 0.00 56.5% 2.3

4/1+4/2 937 937 167 0 0 0.8 0.7 0.1 1.6 6.3 0.4 8.5 0.00 58.6 : 58.6%

2.4

5/1 189 189 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 662 662 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 327 327 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 573 573 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

9/1 836 836 - - - 1.5 0.8 - 2.3 9.7 0.5 11.0 0.00 60.7% 3.0

10/1 677 677 - - - 0.3 0.4 - 0.7 3.8 0.2 3.7 0.00 43.8% 1.0


Selected Data And Results Page 15 Scenario 4: 'PM no peds' (FG2: 'PM peak hour', Plan 2: 'No peds')

Turning Counts Data















Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 44.7%

A5 Ballasalla

- - N/A - - - - - - - - - - 44.7%

1/1 A5 north Left

Right U 1 A 1 18 82 0 - 148 1800 1800 342 43.3%


Ahead U+O 1 B 1 72 5 77 - 455 1980:1800 1980 1429+19

31.4 : 31.4%


Right U 2 E 1 24 28 52 - 201 1800 1800 450 44.7%

4/1+4/2 A5 west

Right Ahead U+O 2 F 1 66 57 23 - 484 1980:1800 1980 1243+91

36.3 : 36.3%




U N/A - - - - - - 88 Inf Inf Inf 0.0%



U 1 C 1 72 5 77 - 560 1914 1914 1397 40.1%


U 2 D 1 66 57 23 - 585 1962 1962 1315 44.5%


Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 39 0 0 6.3 2.0 0.0 8.3 - - - - 44.7% 10.3

A5 Ballasalla

- - 39 0 0 6.3 2.0 0.0 8.3 - - - - 44.7% 10.3

1/1 148 148 - - - 1.5 0.4 - 1.8 45.0 0.9 4.0 0.00 43.3% 2.1

2/1+2/2 455 455 6 0 0 0.6 0.2 0.0 0.8 6.5 0.3 4.5 0.00 31.4 : 31.4%

1.1

3/1 201 201 - - - 1.8 0.4 - 2.2 38.9 0.8 5.1 0.00 44.7% 2.5

4/1+4/2 484 484 33 0 0 0.9 0.3 0.0 1.3 9.4 0.5 5.7 0.00 36.3 : 36.3%

1.7

5/1 198 198 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 380 380 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 88 88 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 622 622 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

9/1 560 560 - - - 0.6 0.3 - 0.9 6.0 0.4 4.7 0.00 40.1% 1.3

10/1 585 585 - - - 0.9 0.4 - 1.3 7.9 0.3 5.7 0.00 44.5% 1.6


Selected Data And Results Page 18 Scenario 5: 'AM Double cycle' (FG1: 'AM peak hour', Plan 3: 'Double cycle with peds')

Turning Counts Data















Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 80.5%

A5 Ballasalla

- - N/A - - - - - - - - - - 80.5%

1/1 A5 north Left

Right U 1 A 2 21 43(126) 50(0) - 228 1800 1800 296 77.1%


Ahead U+O 1 B 2 73 5(81) 38(121) - 464 1980:1800 1980 1042+25

43.5 : 43.5%


Right U 2 E 2 14 42(125) 49(132) - 122 1800 1800 206 59.3%

4/1+4/2 A5 west

Right Ahead U+O 2 F 2 80 137(80) 37(120) - 937 1980:1800 1980 988+214

77.9 : 77.9%




U N/A - - - - - - 327 Inf Inf Inf 0.0%



U 1 C 2 73 5(81) 38(121) - 836 1939 1939 1039 80.5%


U 2 D 2 80 137(80) 37(120) - 677 1934 1934 1133 59.8%


Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 178 0 0 10.1 7.2 0.5 17.8 - - - - 80.5% 22.1

A5 Ballasalla

- - 178 0 0 10.1 7.2 0.5 17.8 - - - - 80.5% 22.1

1/1 228 228 - - - 1.9 1.6 - 3.5 55.6 1.0 7.0 0.00 77.1% 3.9

2/1+2/2 464 464 11 0 0 1.4 0.4 0.0 1.8 13.8 0.7 7.2 0.00 43.5 : 43.5%

2.4

3/1 122 122 - - - 1.0 0.7 - 1.8 51.9 0.9 3.4 0.00 59.3% 2.0

4/1+4/2 937 937 167 0 0 3.2 1.7 0.4 5.4 20.9 0.9 20.4 0.00 77.9 : 77.9%

6.9

5/1 189 189 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 662 662 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 327 327 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 573 573 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

9/1 836 836 - - - 1.2 2.0 - 3.2 13.9 0.5 12.8 0.00 80.5% 3.9

10/1 677 677 - - - 1.3 0.7 - 2.1 11.1 0.7 11.5 0.00 59.8% 2.9


Selected Data And Results Page 21 Scenario 6: 'PM Double Cycle' (FG2: 'PM peak hour', Plan 3: 'Double cycle with peds')

Turning Counts Data















Network Results


Lane Type

Controller Stream


Num Greens

Total Green (s)

Start Green (s)

End Green (s)

Arrow Green (s)

Demand Flow (pcu)

Sat Flow (pcu/Hr)


Capacity (pcu)

Deg Sat (%)


- - N/A - - - - - - - - - - 58.8%

A5 Ballasalla

- - N/A - - - - - - - - - - 58.8%

1/1 A5 north Left

Right U 1 A 2 20 52(130) 62(0) - 148 1800 1800 283 52.3%


Ahead U+O 1 B 2 74 5(93) 47(125) - 455 1980:1800 1980 1066+14

42.1 : 42.1%


Right U 2 E 2 25 50(128) 61(2) - 201 1800 1800 347 57.9%

4/1+4/2 A5 west

Right Ahead U+O 2 F 2 69 7(92) 45(123) - 484 1980:1800 1980 951+70

47.4 : 47.4%




U N/A - - - - - - 88 Inf Inf Inf 0.0%



U 1 C 2 74 5(93) 47(125) - 560 1914 1914 1039 53.9%


U 2 D 2 69 7(92) 45(123) - 585 1962 1962 995 58.8%


Item Arriving (pcu)

Leaving (pcu)







Total Delay (pcuHr)








- - 39 0 0 7.8 3.3 0.1 11.3 - - - - 58.8% 14.3

A5 Ballasalla

- - 39 0 0 7.8 3.3 0.1 11.3 - - - - 58.8% 14.3

1/1 148 148 - - - 1.1 0.5 - 1.7 40.8 0.9 3.5 0.00 52.3% 1.9

2/1+2/2 455 455 6 0 0 1.4 0.4 0.0 1.8 13.9 0.7 7.6 0.00 42.1 : 42.1%

2.4

3/1 201 201 - - - 1.5 0.7 - 2.2 38.6 0.9 4.8 0.00 57.9% 2.5

4/1+4/2 484 484 33 0 0 1.6 0.5 0.1 2.2 16.2 0.7 8.0 0.00 47.4 : 47.4%

2.8

5/1 198 198 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

6/1 380 380 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

7/1 88 88 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

8/1 622 622 - - - 0.0 0.0 - 0.0 0.0 0.0 0.0 0.00 0.0% 0.0

9/1 560 560 - - - 0.8 0.6 - 1.4 9.1 0.5 4.3 0.00 53.9% 1.9

10/1 585 585 - - - 1.4 0.7 - 2.1 12.8 0.7 8.1 0.00 58.8% 2.8



Final 13/08/2020 Page 58/60

APPENDIX C – Swept Path Drawings


Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn

Option 1: Swept Path Analysis(1)


-

Original drg. size


A3L

FINAL

AMS

28/04/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text



Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn



-

Original drg. size


A3L

FINAL

AMS

28/04/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text



Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn



-

Original drg. size


A3L

FINAL

AMS

10/08/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text



Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn



-

Original drg. size


A3L

FINAL

AMS

28/04/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text



Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn



-

Original drg. size


A3L

FINAL

AMS

08/06/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text



Notes:


Scale

Title

Project

Client


prior permission.


ApprovedChecked

Date

Drawn



-

Original drg. size


A3L

FINAL

AMS

09/06/20

GM

A1

NTS

GM

www.systra.co.uk

Prospect House

5 Thistle Street

Edinburgh

EH2 1DF Tel: 0131 460 1847

AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text


AutoCAD SHX Text



Final 13/08/2020 Page 59/60

APPENDIX D – Road Safety Audit

0

Report Ref 89620(1)

Issue Date 1-Jun-20

STAGE 1 ROAD SAFETY AUDIT REPORT OF DESIGN OPTIONS FOR

A5 BALLASALLA LINK ROAD JUNCTION, ISLE OF MAN.

Design Options, A5 Ballasalla Junction, Isle of Man. Road Safety Audit Stage 1

1

CONTENTS

1. INTRODUCTION. .............................................................................................................................. 2

2. PROJECT DETAILS. ........................................................................................................................... 3

3. PROCEDURE .................................................................................................................................... 5

4. PREVIOUS ROAD SAFETY AUDITS. ................................................................................................... 6

5. IDENTIFIED PROBLEMS.................................................................................................................... 7

Local Alignment. .............................................................................................................................. 7

General. ........................................................................................................................................... 7

Junctions.......................................................................................................................................... 8

Walking, Cycling and Horse Riding. ............................................................................................... 10

Traffic Signs, Carriageway Markings and Lighting. ........................................................................ 13

6. JUNCTION OPTIONS. ..................................................................................................................... 15

7. AUDIT TEAM STATEMENT ............................................................................................................. 17

Appendix A. Location Plan of Problems ........................................................................................ 18

Issue / Revision Issue 1 Revision A Revision B Revision C

Report Title Stage 1 RSA, Design Options A5 Ballasalla Junction, Isle of Man.

Document Ref 89620(1)

Document Status Draft

Prepared by Wyllie Lodge Ltd, Road Safety Consultants.

Prepared for Isle of Man Government.

Report Author B. Wyllie.

Signature

Checked by D. Lodge.

Signature

Issued by B. Wyllie.

Signature

Date Issued 01/06/2020.


2

1. INTRODUCTION.

1.1. The objective of a Road Safety Audit (RSA) is to identify any aspects of a road design or

construction scheme that could give rise to road safety concerns and, where possible, to

suggest modifications that would improve the road safety of the resultant scheme. This

report results from a Stage 1 RSA carried out on four design options for a junction on the A5

in Ballasalla, Isle of Man. The audit was instructed by Systra Ltd and was carried out by Wyllie

Lodge Ltd, Independent Road Safety Consultants.

1.2. The Audit Team members were;

Audit Team Leader Blair Wyllie, I Eng, MCIHT, MSoRSA

Audit Team Member David Lodge, BSc, MSc, CMILT, MCIHT, MSoRSA.

Both audit team members hold the Transport Scotland / Highways Agency Certificate of

Competence.


3

2. PROJECT DETAILS.

2.1. The project consists of the conversion of a 3 leg junction to a 4 leg junction to provide access

to and from a new link road that will bypass the village of Ballasalla on the Isle of Man. The

A5 through Ballasalla is the main route between the airport and Douglas, and a mini

roundabout forms its junction with the B53 (Balthane Road). To the north of this junction the

A5 (Station Road) crosses a railway line at a level crossing. There are up to 12 trains a day (6

in each direction) using this crossing.

2.2. This RSA report considers 4 design options for the junction. These being as follows.

Option 1. - A 4 leg roundabout with a 30m ICD.

Option 3. - A signalised crossroads.

Option 5A. - A priority controlled crossroads and a priority T-junction with a right turn

ghost island.

Option 5B. - A signalised crossroads and a signalised T-junction with a right turn ghost

island.

Plans of the proposed options are shown in appendix A.

Location Plan.

Junction

Location

Proposed

Link Road


4

2.3. The information made available for the audit is listed below;

Drawing Ref. Title

1 Rev A 27/04/20 Option 1: Proposed Layout & Dimensions.

1 Rev A 13/05/20 Option 3: Proposed Layout & Dimensions.

1 Rev A 06/05/20 Option 5a1: Proposed Layout & Dimensions.

1 Rev A 13/05/20 Option 5b: Proposed Layout & Dimensions.

Document. Title

Email 28/05/2020. 2018 base peak hour traffic flows and

2028 future peak hour traffic flows.


5

3. PROCEDURE

3.1. The audit was carried out following the general principles and procedures set out in GG 119

of the Design Manual for Roads and Bridges (DMRB), with adaptions to meet the

requirements of the highway authority (Overseeing Organisation), where required. The Road

Safety Audit procedure is not an examination or verification of compliance to a design

standard. Any notified departures from the design standard have been referenced within the

report. The recommendations in this report are considered by the audit team to be

appropriate and proportionate to the concerns and problems identified.

3.2. The audit was carried out between 18th May and 1st June 2020 at the offices of Wyllie Lodge.

Due to travel restrictions imposed during the Covid-19 pandemic no site visit was carried out.

3.3. In accordance with GG 119, the Overseeing Organisation should consider the

recommendations contained within this audit. In doing so, the Overseeing Organisation shall

consult with the Design Team. The design team shall prepare a road safety audit response

report that has been agreed with the Overseeing Organisation and signed by both parties

indicating their agreement on the RSA actions.

3.4. For the purposes of this audit the following are defined as:

Organisation Contact

Overseeing Organisation Dept. of Infrastructure, Isle of Man Government.

Project Promoter Dept. of Infrastructure, Isle of Man Government.

Design Organisation Systra Ltd.

Road Safety Audit Organisation Wyllie Lodge Limited.


6

4. PREVIOUS ROAD SAFETY AUDITS.

4.1. No previous road safety audit has been carried out for this development.


7

5. IDENTIFIED PROBLEMS

Local Alignment.1

No local alignment road safety problems have been identified.

General.

5.1 PROBLEM

Location Options 5A & 5B.

New T junction on link road.

Summary Increased risk of collisions and severity.

The audit team have not been made aware of any forecasted pedestrian or traffic flows

on the new link, or how far north the urban 30mph speed limit will extend to. There will

be an increased risk of collision severity at a junction on a derestricted section of road

within an urban speed limit.

Recommendation

It is recommended that the urban speed limit is extended northwards to cover the

proposed new junction.

5.2 PROBLEM

Location Options 1 & 3.

Summary Increased risk of collisions and severity.

It is understood that the existing properties to the east of the A5 Station Road, between

the junction and the level crossing are to be demolished. This will remove some of the

kerbside parking demand and ease traffic flows, however any future redevelopment of

the area may generate a similar parking demand.

Obstructive parking near level crossings can increase the risk of a vehicle being caught

within the crossing, potentially resulting in a serious injury collision.

Recommendation

It is recommended that the need for waiting restrictions along this section of A5 Station

road are reviewed.

1 DMRB GG-119 standard list


8

Junctions.

5.3 PROBLEM

Location Option 1.

Balthane Road to Station Road south manoeuvre.

Summary Pedestrian and vehicle collision.

Intervisibility between approaching left turn drivers on Balthane Road, and pedestrians waiting

to cross to the A5 may be restricted by a boundary wall and planting. A driver approaching this

dedicated left turn lane may be more focused on identifying a safe gap in southbound traffic

exiting the roundabout, than a pedestrian waiting to cross Station Road from east to west. At the

give way line drivers will be viewing right towards the roundabout out of their driver’s door

window and will be facing away from the crossing, they may not notice a pedestrian stepping off

the footway. This could lead to a driver pulling away from the give way line at the same time as

a pedestrian steps of the footway, potentially resulting in a pedestrian injury collision.

Recommendation

It is recommended that;

1. The sightline is cleared of any obstruction or,

2. The crossing is moved to avoid any obstruction from the boundary wall or hedge.


9

5.4 PROBLEM

Location Option 3.

Statin Road / Balthane Road junction.

Summary

The junction intervisibility may be restricted by adjacent boundaries. Restricted junction

intervisibility is likely to have a detrimental impact on the safety performance of a

signalised junction. It could contribute to drivers and pedestrians not seeing each other in

enough time to prevent a collision.

Recommendation

It is recommended that the junction intervisibility sightlines are cleared of all obstructions.

5.5 PROBLEM

Location Options 5A & 5B.

Station Rd / Balthane Road junction and proposed T-junction.

Summary Increase risk of a turning collision.

Options 5A and 5B show two junctions, a cross roads and a T-junction. Generally collisions

are more likely to take place at junctions, and the more junctions on a road network the

more there will be. It is the opinion of the audit ream that options 5A and 5B will generate

more turning manoeuvres than option 1 or 3 and therefore more collisions.

Recommendation

It is recommended that the design minimises the number of turning manoeuvres.


10

Walking, Cycling and Horse Riding.

5.6 PROBLEM

Location Options 1 & 3.

Pedestrian crossing point Station Road, north of roundabout.

Summary Risk of pedestrian injury from trip or fall.

There is a significant level difference between the existing footway on the west side of

Station Road and the carriageway level. Wheelchair users and other pedestrians with

mobility difficulties may not be able to access the footway from the carriageway if steps

or a steep ramp are provided. This could result in wheelchair users toppling from their

chair and sustaining an injury.

Recommendation

It is recommended that the footway is lowered to match the carriageway level and the

footway is extended all the way to the level crossing to remove the steps at the crossing.


11

5.7 PROBLEM

Location Option 1.

Pedestrian crossing point on new link road, north of the

roundabout.

Summary Increased risk of pedestrian injury collision.

The location of the pedestrian crossing point to the east of the proposed roundabout is

too far east for it to be on a realistic desire line for people walking between Balthane Road

and the A5 Station Road north, towards the village centre. Many pedestrians are likely to

cross at the give way line, increasing their risk of being knocked down by a turning vehicle.

Recommendation

It is recommended the crossing point is located closer to the desire line.

5.8 PROBLEM

Location Option 1.

A5 & new Link Road. Pedestrian crossing points.


The constant flow of traffic at roundabouts can make it difficult for pedestrians to cross

each leg of the junction. Roundabouts in general are not a particularly pedestrian friendly

type of junction choice. Many pedestrians, and in particularly those with mobility

problems or difficulties in judging and accepting safe gaps in traffic flows, are likely to be

at risk of stepping onto the carriageway and being knocked down by a vehicle.

Recommendation

It is recommended the crossing points are controlled crossing points.


12

5.9 PROBLEM

Location Option 1.

Summary Increased risk of cyclist injury collisions.

Roundabouts are a particulate hazardous junction type for cyclists. 12.5% of all cyclist

injury collisions take place at roundabouts2. They require cyclists to have high levels of

skills and confidence to mix with circulatory traffic and change lanes. Cyclist can also be

easily hidden from a driver’s sight by another vehicle and can easily get caught within the

blind spot of a HGV driver.

Recommendation

It is recommended that a shared foot/cycleway is provided around the roundabout.

5.10 PROBLEM

Location Option 5A.

New T-junction on the link road.


An uncontrolled pedestrian crossing point is shown to the east of the proposed new T-

junction. The audit team have not been made aware of any likely pedestrian or traffic

flows on the new link or where the urban 30mph speed limit will start. There will be an

increased risk of pedestrian and vehicle collisions and injury severity at an uncontrolled

crossing within a derestricted section of road, than at a controlled crossing within an urban

speed limit.

Recommendation

It is recommended that a controlled crossing is provided across the new link road.

2 Pedal Cycling Road Safety Factsheet, Table 6, Dept of Transport, March 2018.


13

Traffic Signs, Carriageway Markings and Lighting.

5.11 PROBLEM

Location Option 3.

A5 Station Road level crossing.

Summary Risk of road and rail collisions.

The introduction of traffic signals will result in queuing traffic being closer to the level

crossing than if the junction was controlled by a give way line at a roundabout. Traffic

queuing back towards the level crossing should not be a problem, provided the crossing

is suitably signed and marked. If the crossing is not signed and marked correctly there will

be an increased risk of drivers not complying with the yellow box markings, which may

result in queuing traffic within the controlled area of the crossing, risking potentially

serious road and rail collision.

Recommendation

It is recommended that the detailed design includes for the refreshing and resigning of

the level crossing where necessary.

5.12 PROBLEM

Location Option 3.

A5 Station Road.

Summary Minor non-injury slow speed junction collisions.

It is very likely that during the busiest periods northbound queuing traffic waiting at the

level crossing stop line will tail back to the junction and block the flow of other traffic

through the junction. This may contribute to driver frustration, poor driving standards and

minor non-injury shunt type collisions.

Recommendation

It is recommended that level crossing warning signs with the appropriate distance and

direction sub-plate are provided on all approaches to the junction.


14

5.13 PROBLEM

Location Option 3.

A5 Station Road.

Summary Increased risk of side impact collisions.

The hatched road markings do not appear to cater for right turning traffic from the new

link road into A5 Station Road, northwards. This could lead to confusion and increase the

risk of a driver accepting an unsafe gap in the opposing traffic stream, resulting in a side

impact collision.

Recommendation

It is recommended that;

1. Right turn filter arrows are provided within the traffic signals.

2. The hatching is removed and turning arrows provided to allow for nearside to

nearside (non-hooking) turning manoeuvres.


15

6. JUNCTION OPTIONS.

6.1. The road safety threats and opportunities of each design have been reviewed by the audit

team and the following comments made.

6.2. The two main types of collisions at junctions are approaching collisions and turning collisions.

Approaching collisions are most likely to be vehicle shunts resulting in slight injuries and

turning collisions are most likely to be side impact collisions resulting in a more severe

category of injury than a shunt collision. Failed to look properly was the most frequently

reported contributory factor, involved in 32% of all reported accidents. This was followed by

failed to judge other person’s path/speed (18%).3

Option 1. Roundabout.

Threat Opportunity

Roundabouts present a greater risk to cyclists than a signal controlled junction. Weaving across the circulatory lanes exposes then to risk of a collision with a following vehicle.

Collision severity at roundabouts tends to be lower than at a cross roads, as the angle of impact is likely to be less than that at a cross roads.

Pedestrian routes around a roundabouts are less direct than at a signal controlled junction, and crossing around a roundabout requires greater road safety skills and judgement than at a signal controlled crossing.

Improvements to the west footway on Station Road, between the junction and the level crossing could enable its use by wheelchair users.

Option 3. Signalised crossroads.

Threat Opportunity

Right turning drivers who fail to judge and accept a safe gap in approaching traffic will be at risk of a serious side impact collision.

A safer level of provision for pedestrians and cyclist can be provided at signalised junctions than at a roundabout.

Advance stop lines and or shared foot/cycleway facilities would improve safety for cyclists.

Improvements to the west footway on Station Road, between the junction and the level crossing could enable its use by wheelchair users.

The provision of a right turn filter into Balthane Road will minimise the risk of driver’s trying to accept an unsafe gap in approaching traffic.

3 https://www.transport.gov.scot/media/46069/reported-road-casualties-scotland-2018.pdf

https://www.transport.gov.scot/media/46069/reported-road-casualties-scotland-2018.pdf


16

Option 5A. Priority Junctions.

Threat Opportunity

The straight alignment of the new link road will reduce the rate of compliance to a speed limit.

Shared foot / cycleway provision along the new link road will improve safety for cyclists.


Provide controlled pedestrian crossing points.

More junctions create more risk of driver error and collisions.

Uncontrolled pedestrian crossing rely on pedestrians judging and accepting a safe gap in traffic flows.

Option 5B. Signalised Junctions.

Threat Opportunity

The straight alignment of the new link will reduce the rate of compliance to a speed limit.

Shared foot / cycleway provision along the new link road will improve safety for cyclists.


More junctions create more opportunities for driver error and collisions.

6.3. In considering the foregoing the road safety audit team considers that Option 3, the proposed

signalised junction, will provide the safest junction type for this situation.


17

7. AUDIT TEAM STATEMENT

AUDIT TEAM STATEMENT

DESIGN OPTIONS, A5 JUNCTION, BALLASALLA ISLE OF MAN.

SAFETY AUDIT STAGE 1

We certify that we have examined the works listed in this report. The examination has been carried

out with the sole purpose of identifying any features of design or construction that can be modified in

order to improve the safety of the scheme. The problems identified have been noted in this report

together with recommendations, which should be studied for implementation.

We certify that this Road Safety Audit has been carried out in accordance with GG 119.

Signed……………………………………………………………Audit Team Leader Date 1 June 2020.

Blair Wyllie, I Eng, MCIHT, MSoRSA

Signed……………………………………………………………Audit Team Member Date 1 June 2020.

David Lodge, BSc, MSc, CMILT, MCIHT, MSoRSA.

Wyllie Lodge Road Safety Consultants T 08450 944512

Blair Wyllie [email protected] M 07952269914

David Lodge [email protected] M 07999 957344

WYLLIE LODGE Limited. 23 St Andrew’s Street Ayr KA7 3BT.

http://wyllielodge.co.uk/

18

Appendix A. Location Plan of Problems

Option 1

5.6

5.6

5.3

5.2

5.9

5.9

5.8

5.8

5.7

5.8

5.8


19

Option 3

5.6

5.6

5.12

5.12

5.12

5.11

5.4

5.4

5.2

5.13


20

Option 5A

5.5

5.10


21

Option 5B

5.1 5.5

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