anderson bay sand pit development proposal and ... pastoralbarnbougle, appen… · sector 1 23 9.89...

Mr Richard Sattler

Anderson Bay Sand Pit

Development Proposal and Environmental

Management Plan

APPENDIX D

Traffic Assessment (T EATON)

Traffic Assessment

Proposed Sand Extraction

“Lost Farm”

Waterhouse Road, Barnbougle

S U B M I T T E D B Y :

T E R R Y E A T O N

T r a f f i c E n g i n e e r

2 9 C a r e y ’ s R o a d

B r i d g e n o r t h T a s 7 2 7 7

T E L / F A X : ( 0 3 ) 6 3 3 0 1 5 1 0

M A Y 2 0 1 4 R E V I S I O N 1

Traffic Assessment - Proposed Sand Extraction at “Lost Farm” - Waterhouse Road, Barnbougle 1

May 2014 - Revision 1

By Terry Eaton

C O N T E N T S

Page

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

2. THE SITE ..................................................................... 2

3. THE PROPOSAL ......................................................... 3

4. CARTAGE ROUTE ...................................................... 3

5. TRAFFIC DATA ........................................................... 4

6. ASSESSMENT............................................................. 5

7. CONCLUSION ........................................................... 10

ATTACHMENTS

1. Figure 6.61 - Rural Property Access - Layout for Semi-Trailers 3. Pavement Design Chart



By Terry Eaton

1. Introduction

A proposal is being advanced to develop a sand extraction operation at the “Lost

Farm” property, Barnbougle with access to/from Waterhouse Road.

As part of the assesment process for advancing the project a traffic impact report is

required. This report prepared by Terry Eaton an experienced traffic engineer is

provided for that purpose.

Preparation of the report has included a site visit and discussions with the applicant

and the infrastructure Works Manager, Dorset Council.

2. The Site

The site is an area of sand hills some 7 kilometres east of Bridport accessed by an

internal gravel road junctioning with Waterhouse Road some 6.5 km from Bridport

and just east of a residence, No. 653.

Indications are that the site has been in use for sand supply for some years with

advice that a substantial sand resource is available.

The driveway is gravel surfaced some 3.0 metres wide and aligned at an angle of

some 105 for vehicles travelling from the west. The approach from the west is via

a 10 metre radius curve, throat width at edge of seal some 22 metres with the left

turn exit as a tight curve (some 4.0 metres radius).

Sight distance at the driveway is some 260 metres to the west and some 212

metres to the east, the distance to the east can be increased to some 340 metres

by removal of trees on the inside of the curve some 200 metres further east.



By Terry Eaton

3. The Proposal

The proposal is to extract sand from the site and cart to the port facilities at Bell

Bay with projected tonnages:

Year 1 480,000

Year 2 830,000

Year 3 plus 1,500,000

Longer term consideration is to be given to providing for direct loading from the site

to freight by sea.

4. Cartage Route

The proposal is to initially cart from the site by road to the Bell Bay Port facility. The

cartage route to be via:

Waterhouse Road

This road could be considered as a rural sub-arterial link connecting between

Gladstone, the Waterhouse primary production area, tourist facilities and the

north-eastern coastal resort areas to Bridport and areas further west.

Waterhouse Road is generally constructed with a pavement width of some 6.0

metres, gravel shoulders some 0.6 metres wide, grass verges and earth side

drains, the grass verges are some 5 metres wide.

The road alignment from the site access to Bridport is a series of straights and

curves with a relatively flat profile.

The road has been in use by large commercial vehicles carting to major

projects further east and is considered satisfactory for that use.

Indicative travel speed on Waterhouse Road is some 90 to 95 km/h.

A review of the Dorset Council’s road asset management report indicates that

the section of road required for cartage use is in fair to good condition. The

condition assessment being based on the anticipated future use consistent

with the present traffic demand.



By Terry Eaton

Emily Street

This street connects between Bridport - Waterhouse areas and Bridport Main

Road. The road is constructed with a sealed pavement some 8.0 metres wide,

is straight and relatively flat. Some 20 years residual life is considered as a

reasonable provision for future reconstruction timing.

Bridport Main Road

This road is a State maintained road classified as a Category 2 road in the

Tasmanian State Road Hierarchy. The road is classified for use by heavy

inter-regional and sub-regional freight movement. The proposed sand cartage

is considered consistent with this road function.

5. Traffic Data

Limited traffic data is available for Waterhouse Road and Emily Street but casual

traffic counts suggests typical daily volumes at:

(1) Waterhouse Road - some 600 vehicles per day including some 80

commercial vehicles including 16 semi-trailers.

(2) Emily Street - some 1,200 vehicles per day including some 120 commercial

vehicles including 20 - 25 semi-trailers.

(3) Proposed Sand Cartage

(i) Light vehicles - some 10 vehicles per day for the site

operations.

(ii) Heavy vehicles

Vehicle Fleet

Loaded Trips per Day

Total Daily Trips

Two-Way Volume

Year 1 8 6 48 96

Year 2 14 6 84 168

Year 3 plus 26 6 156 312



By Terry Eaton

The proposal is to use rigid truck/tailer combination vehicles with payloads of

some 35 to 39 tonne.

6. Assessment

6.1 Sand Extraction Access

In view of the relatively high heavy vehicle use with almost all trips to/from

the west upgrading the access road junction for two-way use with turn

provisions as per Austroads Part 5 figure 6.61 is considered prudent.

Sight distance to approaching vehicles from the west is in excess of DIER

requirements for a 100km/h approach speed.

Sight distance to the east meets DIER requirements for a 90km/h approach

speed, this distance can be increased by removal of trees from the inside of

the curve just east of the access way, removal of trees to provide 250m sight

distance is suggested.

In view of the relatively high volume of heavy vehicles carting from the site

compared to expectations in the rural location the installation of “Truck

Turning” warning signs. Sign W5-22 “B” size on the road approaches to the

driveway is considered prudent.

6.2 Traffic Service

Waterhouse Road

Aggregation of the existing volume with the predicted traffic generation

for the proposed plus 3 year sand extraction and cartage indicates typical

daily values of:

Existing 520 light vehicles

80 CV’s

Total 600



By Terry Eaton

Sand extraction 10 light vehicles

312 CV’s

Total 322

Estimated total daily volume 922 vehicles

Estimated peak hour volume 90 - 95 vehicles

Calculation of the roadway capacity for level of service “B” provisions

indicates a capacity of 130 vehicles per hour with estimated peak hour

flows at some 90-95 vehicles per hour, i.e. less than the road capacity.

Note - level of service “B” is a high level of service and is accepted as the

zone of stable flow, drivers have reasonable freedom to select their

desired travel speeds. Level of service values are defined between ”A” -

as excellent traffic conditions to “F” - forced flow with level of service “B

considered to provide for very efficient road use.

Emily Street

Existing 1,100 light vehicles

120 CV’s

Total 1,220 vehicles daily

Sand extraction 10 light vehicles

312 CV’s

Total 322 very efficient road use

Total daily volume 1,542 vehicles

Estimated peak hour volume some 180 to 185 vehicles



By Terry Eaton

Calculations of the peak hour capacity indicates a level of service “B”

value of some 240 vehicles per hour, this value is well in excess of the

estimated peak hour two-way volume of some 180 - 185 vehicles per

hour. Note - the normal level of service adopted for urban area planning

is LOS ”C. The Emily Street LOS “C” value is some 500 vehicles per

hour. Note - the LOS values have been calculated taking into account

the predicted plus 3 year heavy vehicles traffic.

6.3 Pavement Considerations

Existing Condition

Council’s Road asset system lists the sections of Waterhouse Road

required for the cartage as:

Sector Segment Length Distance Assessed Useful Life

(yrs)

Remaining life at

2013 (yrs)

ARRB Reassessed Life at 2013

1. 4281 1425 1425 50 18 43

2. 4282 1520 2945 50 14 45

3. 4283 309 3254 50 37 68

4. 4284 2056 5310 50 0 31

5. 4285 2283 7593 50 20 45

Comparison between the asset data base and a visual inspection

indicates most of the road pavement is in average condition except for a

400 metre section in sector 2 where surface deformation is apparent and

a 900 metre length in sector 3 considered in average to poor condition.

Analysis of the present heavy vehicle use of the road suggests annual

ESA’s at 4.3 x 104.

Aggregating this use over an indicative useful life of 55 years suggests

the design traffic number at 2.35 x 106 with an indicative pavement

depth of some 350 mm thickness CBR 7.



By Terry Eaton

Note: The indicative pavement thickness is a theoretical value based on

the modified pavement life of 55 years with a typical CBR value.

Experience suggests sub base CBR values are modified (increased) due

to traffic loading indicating that roadside drainage and increasing the

present pavement thickness as the least cost upgrade strategy.

Residual ESA’s

Based on a 55 year pavement life the residual ESA’s per pavement

sector are estimated at:

Remaining Life

(estimate) Residual ESA’s

Sector 1 23 9.89 x 105

Sector 2 19 8.17 x 105

Sector 3 42 18.0 x 105

Sector 4 5 2.15 x 105

Sector 5 (part) 25 10.75 x 105

Sand Cartage

The anticipated sand cartage suggests:

Cartage (tonne) ESA’s

Year 1 480,000 6.8 x 104

Year 2 830,000 11.76 x 104

Year 3 plus 1,500,000 21.25 x 104

Based on a 5 year cartage provision the sand cartage ESA’s are some

8.2 x 105.



By Terry Eaton

Comment

Waterhouse Road

Comparison between the residual ESA’s and the predicted cartage

loading indicates:

Residual Life Reduction in

Residual Life With Sand Cartage

Sector 1 6 years 74%




Sector 5 part 6 years 76%

This analysis indicates almost all the length of Waterhouse Road

required for cartage of the sand will need reconstruction within 6 years,

sector 4 requiring reconstruction within 2 years of the commencement of

cartage with the best section of road - sector 3 limited to 10 years

residual life.

Emily Street

Limited information is available for the pavement condition for this street

with visual inspection suggesting the condition similar to Waterhouse

Road sector 2 - some 20 years residual life. Indications are that with the

sand cartage the pavement condition will require reconstruction after

some 5 years of sand cartage.

Note

It should be noted that this is a theoretical assessment limited by

available data. The assessment indicates that most of the Dorset

Council road network to serve this proposed development will be at risk

of failure within some 6 years of cartage commencing with the resource

extraction tonnages as programmed.



By Terry Eaton

In view of the high costs to reconstruct the road network it may be

prudent to undertake a more robust evaluation of the road condition,

including pavement and sub base measurements plus pavement

deflection values to establish the reconstruction standard.

This analysis indicates potential issues with pavement condition with the

sand cartage and with some variance in the present pavement condition

assessments.

It is suggested that a joint road condition assessment be arranged by the

Dorset Council and the developers as the basis for any agreement on

cost contributions prior to cartage commencing.

7. Conclusion

A traffic assessment for the cartage route required for a proposed sand extraction

operation using Waterhouse Road has found no safety or traffic service issues

associated with the proposal, with indications that a high level of service will be

available for both Waterhouse Road and Emily Street

However, analysis of the existing roadway indicates a high likelihood that pavement

upgrade works will be required to ensure satisfactory road conditions are

maintained for the ongoing use of the road.

Terry Eaton

Pavement Life (Years)

ATTACHMENT 1

ATTACHMENT 2

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