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TRL Limited

APPLICATION GUIDE 63 (Issue G)

TRANSYT 13 USER GUIDE

by James C Binning, Graham Burtenshaw and Mark Crabtree.

© Copyright Transport Research Laboratory 2010. All rights reserved.

abcdefg

TRL SoftwareCrowthorne House

Nine Mile RideWokingham Berkshire

RG40 3GA United Kingdom

Tel: +44 (0)1344 770758Fax: +44 (0)1344 770356

E-mail: [email protected]

mailto:[email protected]:[email protected]://www.trlsoftware.co.uk/


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TRANSYT 13 User Guide (Issue G)

The information contained herein is the property of TRL Limited. Whilst every effort hasbeen made to ensure that the matter presented in this document is relevant, accurate andup-to-date at the time of publication, TRL Limited cannot accept any liability for any erroror omission.

First Published 2008

ISSN 1365-6929

Windows, Windows XP, Windows Vista, Windows 7 and Outlook are registered trademarksof Microsoft Corporation.

WinZip is a registered trademark of WinZip International LLC.

Aimsun is a trademark of TSS-Transport Simulation Systems, S.L.

Aimsun is a product of TSS-Transport Simulation Systems, S.L.

VISSIM is a product of PTV AG

TRANSYT-7F (an adaptation of TRL’s original TRANSYT 7 software product) is developed andmaintained by McTrans (University of Florida).

Other products and company names mentioned herein may be the trademarks of their respective

owners.


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ABSTRACT OF APPLICATION GUIDE 63 2008

TRANSYT is an off-line computer program for determining and studying optimum

fixed time, co-ordinated, traffic signal timings in any network of roads for which theaverage traffic flows are known. A traffic model of the network calculates aPerformance Index (PI) in monetary terms, which is a weighted sum of all vehicledelay and stops. An optimising routine systematically alters signal offsets and/orallocation of green times to search for the timings which reduce the P.I. to aminimum value. TRANSYT is the most widely used program of its type throughoutthe world.

This Application Guide provides a comprehensive user’s guide to the latest version

of TRANSYT software (TRANSYT 13) issued by TRL. It has been updated to includedetails of the changes made since TRANSYT 12; in particular the addition of thefully-interactive graphical interface, an alternative to the platoon dispersion model -the cell-transmission model, new extended data ranges and the ability to build agraphical representation of a network upon which results can be displayed using the

fully integrated network construction editor.


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TRANSYT 13 user guide

January 2010, Issue G (to accompany TRANSYT 13.1.2)

For program advice, sales and distribution information pleasecontact:

TRL Software Sales

Address:TRL Software SalesTRLCrowthorne House

Nine Mile RideWOKINGHAMBerkshireRG40 3GAUnited Kingdom

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Telephone lines: +44 (0)1344 770758+44 (0)1344 770558

Fax: +44 (0)1344 770356

E-mail: [email protected]: www.trlsoftware.co.uk

--------------------------------------------------------------------If you wish to receive regular information (by e-mail)

about this product and other TRL software products youcan subscribe to TRL’s free ‘Software E-news’ electronicnewsletter via our web site. This includes maintenance

update information, articles on new releases, frequentlyasked questions (FAQs), and information on training

courses available.

This publication supplements ‘TRL Software News’, ourquarterly newsletter, which is distributed to maintenanceholders.

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CONTENTS

1 Introduction .............................................................................. 15

1.1 About TRANSYT ........................................................................... 15

1.2 Summary of TRANSYT 13 improvements ......................................... 16

1.3 About this manual ........................................................................ 17

1.4 Related Software ......................................................................... 18

1.5 Product Background and Versions .................................................. 19

1.6 Software Updates and Download system ......................................... 20

1.7 Acknowledgements ...................................................................... 20

2 Installing the Software ............................................................... 21

2.1 Hardware/software requirements ................................................... 21

2.2 Installing/uninstalling the software................................................. 21

2.3 Copy-protection and software registration ....................................... 21

3 Modelling Basics ........................................................................ 23

3.1 Traffic Model – Basic Assumptions .................................................. 23

3.2 Network representation ................................................................ 23

3.3 The relationship between lanes and links ........................................ 23

3.4 Flow, speed and link data ............................................................. 24

3.5 Signal settings ............................................................................. 27

3.6

Traffic behaviour within a link ........................................................ 31

3.7 Delays, Queues and Stops ............................................................ 32

3.8 Maximum queues ......................................................................... 33

3.9 Give-way situations ...................................................................... 35

3.10 Shared stop lines ......................................................................... 35

3.11 Flared Approaches ....................................................................... 36


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4 Optimisation Basics ................................................................... 37

4.1 Network timings optimisation ........................................................ 37

4.2 Cycle Time optimisation ................................................................ 37

5 How to use TRANSYT 13 ............................................................. 39

5.1 Essential GUI terms you need to know............................................ 39

5.2 Quick start for TRANSYT users ....................................................... 39

6 General Graphical User Interface (GUI) operation .......................... 49

6.1 General ...................................................................................... 49

6.2

Getting help ................................................................................ 49

6.3 Accessibility ................................................................................ 50

6.4 Demo (and Viewer) mode ............................................................. 50

6.5 Speed of operation ....................................................................... 51

6.6 Main toolbars .............................................................................. 52

6.7 Changing the Active Data Item ...................................................... 53

6.8

Padlock system ............................................................................ 54

6.9 The 'Edit in Window' System ......................................................... 56

6.10 Types of Data .............................................................................. 58

6.11 Running Files and using Auto-Run .................................................. 62

6.12 Managing files ............................................................................. 63

6.13 Undo/Redo .................................................................................. 64

6.14

Copying data to the clipboard ........................................................ 65

6.15 Printing ...................................................................................... 66

6.16 Managing Windows ...................................................................... 66

6.17 Preferences Screen ...................................................................... 66

7 TRANSYT 13 Input Data ............................................................. 69

7.1 Data Files ................................................................................... 69

7.2

Data Outline ................................................................................ 69


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7.3 Data Outline Screen ..................................................................... 72

7.4 Data Editor Screen ....................................................................... 73

7.5 Data Grids .................................................................................. 74

7.6 Network Construction Editor (NetCon) ............................................ 74

7.7 Task List ..................................................................................... 75

7.8 Data Field Finder ......................................................................... 76

8 Other Data Entry Screens ........................................................... 77

8.1

Data Grids .................................................................................. 77

8.2 Query Builder .............................................................................. 87

8.3 Main Data Screen ......................................................................... 91

8.4 Nodes Data Screen ...................................................................... 92

8.5 Links Data Screen ........................................................................ 92

9 Network Construction Editor (NetCon) .......................................... 95

9.1 Speed of operation ....................................................................... 96

9.2

Moving around the network ........................................................... 96

9.3

Printing, copying and exporting ..................................................... 97

9.4 Manipulating items ....................................................................... 97

9.5 Viewing and visualising data in NetCon ......................................... 100

9.6 Other toolbar buttons ................................................................. 112

9.7 NetCon Options screen ............................................................... 113

9.8 Other NetCon Features ............................................................... 116

10 Working with Analysis Sets, Demand Sets and Time Segments .. 117

11 Working with Traffic Flows ..................................................... 123

11.2 Link Flows Consistency Diagram Screen ........................................ 125

11.3 Flow Allocation Tool.................................................................... 128

12 Working with Traffic Signals ................................................... 137


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12.1 Introduction to traffic signals in TRANSYT 13 ................................. 137

12.2 TRANSYT 12 and TRANSYT 13 modes ........................................... 144

12.3 Link Timings Screen ................................................................... 155

12.4 Intergreen Matrix Screen ............................................................ 166

12.5 Stage Sequence Screen .............................................................. 168

12.6 Link Delays ............................................................................... 169

12.7 Start/end displacements ............................................................. 170

13 Working with Results ............................................................ 173

13.1 Summary Results Screen ............................................................ 173

13.2 Detailed results ......................................................................... 175

13.3 Animation controls ..................................................................... 176

13.4 Graphs ..................................................................................... 177

13.5 Time Distance Diagram ............................................................... 184

14 Generating Reports ............................................................... 191

14.1

About Report Files ...................................................................... 191

14.2

Report Viewer ........................................................................... 192

14.3 Reporting Options ...................................................................... 194

14.4 Using custom grid layouts in reports ............................................ 195

15 TRANSYT 13 Outputs ............................................................ 197

15.1 Traffic model predictions ............................................................. 197

15.2

TRANSYT individual-link predictions.............................................. 199

15.3 TRANSYT network-wide results .................................................... 205

16 Additional Tools and Features ................................................ 209

16.1 Find Best Route ......................................................................... 209

16.2 TRANSYT 12 Card Viewer Screen ................................................. 209

16.3 Merging Networks ...................................................................... 210

16.4

Saturation Flow Estimation .......................................................... 211


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16.5 QUEPROB - Effective Flare length calculator .................................. 212

16.6 Drive-on-the-left/Drive-on-the-right ............................................. 214

16.7 X-Y Graph Generator .................................................................. 214

17 Traffic Behaviour Models (PDM/CTM) ...................................... 219

17.1 Platoon dispersion model (PDM) ................................................... 219

17.2 Cell Transmission Model .............................................................. 225

17.3 PDM versus CTM ........................................................................ 229

17.4

Selection of the CTM .................................................................. 229

17.5 Restrictions on use of the CTM ..................................................... 230

18 TRANSYT model features in detail ........................................... 231

18.1 Signal settings ........................................................................... 231

18.2 Delays ...................................................................................... 231

18.3 Stops ....................................................................................... 233

18.4 Wasted green time ..................................................................... 235

18.5

Give-ways ................................................................................. 236

18.6

Shared stop lines ....................................................................... 242

18.7 Flared approaches - the ‘traditional’ method .................................. 244

18.8 Flared approaches – the CTM method ........................................... 249

18.9 Bus and Tram Links .................................................................... 249

18.10 Pedestrian Links ..................................................................... 254

18.11 Routes .................................................................................. 254

18.12 Traffic Profile Types ................................................................ 255

18.13 Fuel consumption estimates ..................................................... 256

19 TRANSYT Optimisation in detail .............................................. 259

19.1 The performance index ............................................................... 259

19.2 Optimisation of green times ........................................................ 264

19.3

Initial ‘EQUISAT’ settings ............................................................ 265


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19.4 Queue-length reductions ............................................................ 265

19.5 Node groups.............................................................................. 267

19.6 Cycle time selection ................................................................... 267

19.7 Cycle Time Optimiser (including CYOP) ......................................... 268

19.8 Multiple cycling and repeated greens ............................................ 270

19.9 Considering the effect of small changes ........................................ 272

20 Modelling Examples .............................................................. 275

20.1

Supplied Data Files .................................................................... 275

20.2 Example 1 – A small network (TRL1.T13) ...................................... 276

21 Modelling Signalised Roundabouts .......................................... 281

21.1 About this chapter ..................................................................... 281

21.2 Introduction .............................................................................. 281

21.3 The TRANSYT program ............................................................... 282

21.4 Modelling a roundabout .............................................................. 282

21.5

Checking co-ordination ............................................................... 292

21.6

Example 2 – a signalised motorway roundabout ............................ 293

21.7 Example 3 – an urban signalised roundabout ................................. 305

21.8 Recommendations ..................................................................... 309

22 Definitions / Glossary ............................................................ 311

22.1 TRANSYT 13 GUI Terms .............................................................. 311

22.2

Modelling and Traffic Engineering Terms ....................................... 312

23 References .......................................................................... 323

24 Appendix A - Importing from TRANSYT 10/11/12 ..................... 325

25 Appendix B – Exporting to TRANSYT 12 ................................... 326

26 Appendix C – Importing from TranEd 2 ................................... 327

27 Appendix D – Importing from TRANSYT-7F .............................. 329


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28 Appendix E – Using OSCADY PRO ........................................... 333


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Installing the Software Page 15


1 Introduction

The timings of signals at road junctions have an important effect on the levels of traffic congestion.

Often, junctions in urban areas form part of a network of co-ordinated signalised junctions. By co-ordinating groups of signals within a network, substantial reductions can be made to queues anddelays. Each group of signals are operated on a common cycle time. Their relative green timesare set so that known average volumes of traffic can travel through the urban area with as littledelay and as few stops as possible.

1.1

About TRANSYT

TRANSYT is an internationally-recognised computer program for finding, and studying, the ‘best’

fixed time plans with which to co-ordinate the traffic signals in networks.

The TRANSYT method has, as shown in Figure 1-1, two main elements; the traffic model and thesignal optimiser.

The model represents traffic behaviour in a network of streets in which most junctions arecontrolled by traffic light signals. The model predicts the value of a ‘Performance Index’ for thenetwork, for any fixed-time plan and set of average flows that is of interest. The PerformanceIndex is a measure of the overall cost of traffic congestion and is usually a weighted combination

of the total amount of delay and the number of stops experienced by traffic.

The optimisation process adjusts the signal timings and checks, using the model, whether theadjustments reduce the Performance Index or not. By adopting only those adjustments whichreduce the Performance Index, subject to minimum green and other constraints, signal timings

are successively improved. The model also provides for give-way priority control possibilities,including the modelling of opposed offside-turn traffic within signalled junctions.

Signalised roundabouts can be modelled and their delay minimised by calculating timings which

reduce blocking-back by keeping the circulating carriageway free flowing.

TRANSYT, at the time of writing, can model up to 200 nodes and 1000 links within a network.TRANSYT is suitable for both drive-on-the-left and drive-on-the-right operation.


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Figure 1-1 The structure of the ‘TRANSYT’ program

Many of the principles behind TRANSYT 13 are essentially the same as those at the heart ofprevious versions of the program. However, TRANSYT 13 brings with it a number of significantmodelling changes as well. All of these changes are described in detail in other chapters.

Although existing uses of previous versions will identify many modelling changes, concessionshave also been made to those familiar with previous versions of TRANSYT, where we thought it isuseful to do so.

1.2

Summary of TRANSYT 13 improvementsThis section allows existing users of TRANSYT 12 to quickly familiarise themselves with what haschanged and what new facilities have been added to TRANSYT 13 by summarising the changesand improvements. Full descriptions of the changes and how to use the new features are to befound in other chapters.

CTM (cell transmission model) allowing the modelling of blocking back effects andgraphical animation of traffic cells throughout the network

Improved opposed offside-turn model

Works directly with link/phase timings and intergreen matrices

Time-varying traffic flow conditions catered for


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Multiple demand sets and signal sets

Explicitly defined pedestrian and tram links

Enhanced P.I. (signal timing) optimisation

Flow O-D data specification and automatic allocation to link flows

New dynamic graphical user interface

New network drawing tool – fully integrated, fully interactive and improved

Graphical cycle-time optimisation

Graph generator, including a ‘universal’ X-Y graph

Graphical colour reporting

Customisable report tables (via the Data Grid)

Time-Distance diagrams

Point-to-point journey time calculation

US HCM 2000 Level of Service calculation

Each signalised link is now associated with a signals node and independently, a traffic

node. This separation in TRANSYT 13 allows certain special cases to be modelled in amore straightforward way

Nodes can be double, triple, and quadruple-cycled, and each link can have up to fourgreen periods

New outputs, including un-weighted P.I., wasted green time, end-of-red/green queues

Various data ranges extended e.g. size of network, number of upstream links andshared links, increased

Third-party product ‘File Import’ options

Many other features

Please browse through this User Guide for information about the many other features in

TRANSYT 13, looking for the following symbols:

1.3

About this manual

The coverage of this user guide is comprehensive and is intended for anyone who is likely to beinvolved with the use of TRANSYT 13. It is hoped that new users will quickly understand theprogram by reading, and by reference to this manual.

To achieve these aims, this user guide describes, in separate chapters, how to get startedquickly with TRANSYT 13 (particularly if you are already familiar with previous versions), data-entry including full details of all the features of the graphical interface, the theory and researchincorporated in TRANSYT and how a TRANSYT model should be specified (including guidance on

how to measure data). Also described is the output and how it should be interpreted. A numberof examples have been included to aid in the understanding of individual junctions and themodelling problems they pose.

Whilst it is desirable to read as much of each chapter as possible, it is accepted that sufficienttime will not always be available. Hence the earlier chapters concentrate on all the essentials


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needed to get started with TRANSYT, with reference within these earlier chapters to othersections of the guide where necessary.

The following icons are used throughout to highlight relevant points about the topics being

covered.

is used to emphasise important points;

is used to warn of the consequences of doing something wrong;

is used to highlight features in TRANSYT 12 that are new to TRANSYT

In many places it is inevitable that “jargon” will have been used, which include general trafficengineering terms, specific TRANSYT terms and terms relating to features of the graphicalinterface. To help avoid repeated explanation of such words and phrases a glossary of terms isincluded (see Chapter 22).

The graphics within this document assume drive-on-the-left situations. However, the terms “nearside” and “offside” have been used throughout, instead of “left” or “right” to allow

understanding for both drive-on-the-left and drive-on-the-right situations.

1.4

Related Software

TRANSYT is only one of a number of thoroughly researched and developed traffic-relatedsoftware products that TRL produce and market commercially. TRL software products arevalidated against a wealth of real life data and used world-wide. Those products which are

related to TRANSYT or most relevant to those using TRANSYT are listed below:

OSCADY PRO is designed to model isolated (uncoordinated) signalised junctions. It is used

to assess performance of junctions in terms of capacity, queue lengths and delays. One of itsmany key features is its phase-based optimisation of signal timings to minimise delay, ormaximise capacity by automatically selecting suitable stage orders and associated phasesequences. This allows very quick assessments of both simple and complex cases to be made.

Data import from, and export to TRANSYT is provided.

OSCADY CLASSIC is (like OSCADY PRO) designed to model isolated (uncoordinated)signalised junctions, but optimises using a stage-based approach. Although less flexible thanOSCADY PRO, those more familiar with stage-based optimisation may find this productparticularly useful.


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TRANSYT-VISSIM LINK is an award-winning* software tool that imports aVISSIM network into TRANSYT 13 and then uses the TRANSYT signal optimiser inconjunction with the VISSIM model to produce an optimum set of signal timings.

Furthermore, it can be used to visualise, validate and edit signal plans for a

VISSIM network. *ITS (UK) 2009 Forward Thinking award for innovation.

TRANSYT-Aimsun LINK is a software tool that imports a AIMSUN network intoTRANSYT 13 and then uses the TRANSYT signal optimiser in conjunction with the AIMSUN modelto produce an optimum set of signal timings. Furthermore, it can be used to visualise, validateand edit signal plans for a AIMSUN network.

PICADY is for predicting capacities, queue lengths and delays (both queueing and geometric)at unsignalised major/minor priority junctions. It is an aid in designing new junctions as well asassessing the effects of modifying existing designs. PICADY includes accident prediction.

ARCADY is for predicting capacities, queue lengths and delays (both queueing and geometric)

at roundabouts. It is an aid in designing new junctions as well as assessing the effects ofmodifying existing designs. ARCADY includes accident prediction.

All these programs are concerned only with the optimisation and operational performance ofindividual junctions or networks. For the overall economic appraisal of wider based road

schemes, an economic appraisal will be required and this can be achieved by use of the UKDepartment for Transport’s cost-benefit analysis program COBA.

For further details of all these programs, and for latest news, current pricelists and purchasing

information, please visit www.trlsoftware.co.uk.

1.5

Product Background and Versions

Investigations carried out in the UK into possible improvements in traffic control of urbannetworks in the 1960’s resulted in the development of TRANSYT/1 in 1967 by the TransportResearch Laboratory (TRL). Two trials of TRANSYT were carried out – one in Glasgow andanother smaller one in West London. The full-scale Glasgow trials were carried out with thecooperation of the City Council in Glasgow. TRANSYT signal timings went ‘live’ in May 1967.TRANSYT was shown to reduce the average journey times through the network of signals inGlasgow by about 16 per cent. A similar reduction was recorded in the other smaller trial inLondon. Because of TRANSYT’s international appropriateness TRANSYT is now one of the most

widely used signal timing programs in the world.

TRANSYT has continued to be developed by TRL ever since its first release. TRANSYT 13represents the single biggest advancement of the product in years – in terms of its traffic model,its features, and its presentation.

1.5.1 TRANSYT 13.1

TRANSYT 13.0 (released in April 2008) was the first release of TRANSYT 13.

TRANSYT 13.1 was release in April 2009. For details of changes due to maintenance releases,e.g. 13.1.x, please refer to release notes supplied with the software and/orwww.trlsoftware.co.uk.

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


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This User Guide is updated for each maintenance release where appropriate. Changesintroduced for TRANSYT 13.1 are marked in the User Guide with the sign:

A summary of these changes is given below:

Flow O-D data specification and automatic allocation to link flows

Time-Distance diagrams

Point-to-point journey time calculation

Enhanced ‘File Import’ options, i.e. import of TRANSYT-7F (.TIN) files

Enhanced data-grid, allowing mixed input and output data in one grid

US HCM 2000 Level of Service calculation

Improved Report contents selection

Automatic Software Update Information SystemVarious minor GUI enhancements

Various minor NetCon enhancements

1.6 Software Updates and Download system

It is useful to the user of any product to know whether or not the particular release they areusing is the most up-to-date available. In order to provide this information automatically, onlaunching TRANSYT, it will try to connect to the TRL Update Information Server. If this

connection is achieved and/or permitted by the user (permanently or as a once-off), the bottomhorizontal status bar will display news concerning TRANSYT such as “NEW TRANSYT 13.1.0.63

Version Available” (as shown below) or “No Update Information Available”

The displayed text is simply the title of the full information available on our server. Clicking onthe link will bring up the full message.

The update information system does NOT install any software or affect your

installation or operation of TRANSYT – including cancelling the link and/or ignoringthe messages. We would however recommend that messages that indicate a new

release is available are read and acted upon if necessary, as new releases maycontain new features and repairs which users will benefit from.

If having read about a new release, you wish to download it, current maintenance holders can goto the TRL download system at http://www.trlsoftware.co.uk/downloads and follow theinstructions on the web page.

1.7 Acknowledgements

The work described in this report was carried out in the Transportation Division of the Transport

Research Laboratory. The authors are grateful to Mark Crabtree who carried out the technicalreview and auditing of this software product. The authors are also grateful for thedocumentation associated with earlier versions of TRANSYT and to their authors.

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


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2 Installing the Software

2.1

Hardware/software requirements

TRANSYT 13 will run on any modern PC under Windows 7, Windows Vista or Windows XP and assuch there are no specific hardware or software requirements other than those of a modern PCcapable of running standard Windows desktop applications.

As may be expected, the program will run more smoothly on a PC with a fast processor andplenty of RAM; this will be particularly noticeable if working with large networks and/or using theCTM traffic model.

Recommended hardware and software requirements are as follows:

• A PC with a 2GHz processor or faster• Windows 7/Vista/XP• 1GB RAM

• 50 MB available hard disk space.• A monitor with a resolution of 1280x1024 or higher. A dual monitor display can be useful

if working with large networks or if you wish to work with many screens at once.• a modern graphics card with hardware accelerated OpenGL capability

TRANSYT 13 may run on versions of Windows other than Windows 7/Vista/XP but this is notguaranteed and is not formally supported.

Some non-essential features of earlier releases of TRANSYT 13 do not work fully on Windows 7.It is therefore advisable to obtain the most recent release before installing onto Windows 7.

2.2 Installing/uninstalling the software

To install the software, browse the product CD for SETUP.EXE, and run this file. This will launchthe product installer. If you have been supplied with the product as a zip file, extract all thezipped files to a temporary folder, and then run SETUP.EXE from this temporary folder.

During installation, all necessary files are copied to the specified folder and an entry added to

the Windows Start menu.

To uninstall the software, please use the Windows Add/Remove Programs system, which isavailable from the Windows Control Panel.

2.3 Copy-protection and software registration

TRANSYT is a copy-protected software product. Having installed TRANSYT it will initially run in a ‘DEMO’ mode and in order to use the full product you must register it with the TRL SOFTWARE .

Moving the system date of your PC backwards is likely to un-register anyregistered versions of this product.


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There are currently two variations of TRANSYT with different copy protection schemes – stand-alone PC copy-protection and network copy-protection (concurrent licence version).

2.3.1 Stand-alone version

Each installation of the stand-alone version of TRANSYT must be registered. Full setupinstructions are available in the file “SOFTWARE REGISTRATION.PDF” provided with thesoftware.

This document includes instructions on how to transfer your registered product from one PC toanother. Read these before you lose access to your old PC!

Depending on the situation, it is also possible to upgrade licences. This usually happens whenpurchasing the full version of a product after previously leasing it. In this situation the software

licence can be upgraded. Again, see the file “SOFTWARE REGISTRATION.PDF” for fullinstructions

2.3.2 Network copy-protected (concurrent licence) version

The concurrent licence version works only on PCs with access to a LAN network and allows up to

a fixed number of PCs to run the product at the same time. In order to use the full product youmust setup the software as a Network Client.

Full setup instructions are available in the file “SOFTWARE NETWORK REGISTRATION.PDF” provided with the software.


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Modelling Basics Page 23


3 Modelling Basics

This chapter gives an overview of the TRANSYT traffic model. Existing users of TRANSYT can

probably skip this chapter, other than those sections marked with the ‘NEW’ symbol. Detailshave been kept to a minimum in order to keep the emphasis on getting to know how to useTRANSYT quickly, providing just enough background prior to using TRANSYT. However,TRANSYT is a complex program, so there are many references to the other chapters throughoutthis one. These chapters will still need to be read in order to be able to correctly model specific

network features, such as flares.

Note: It is assumed that the reader is familiar with traffic engineering terms such as phase,stage and stage sequence. For those new to the subject, or wishing to clarify, please see theDefinitions / Glossary .

3.1

Traffic Model – Basic Assumptions

TRANSYT makes the following assumptions about the traffic situation:

1. Junctions within the network are predominantly signalised.

2. All the signals in the network have a common cycle time or a cycle time a half,third or quarter of this value; details of all signal stages and their minimum

periods are known.

3. For each distinct traffic stream flowing between junctions, or turning at junctions, the flow rate, averaged over a specified period, is known and assumed

to be constant1.

3.2 Network representation

The network being modelled is represented by ‘nodes’ inter-connected by ‘links’. Each signalledintersection is represented by a node. Each distinct one-way traffic stream leading to a node isrepresented by a link.

3.3

The relationship between lanes and linksThe relationship between traffic lanes and links depends on how traffic uses the lanes on the road.A single link may be used to represent one or more traffic lanes. Traffic on one approach may berepresented by one or more links.

In general, one link is required to represent each distinct queueing situation that occurs. Thus,trivial queues may not warrant representation by a separate link. However, a separately-signalled

offside turn traffic stream, with a significant flow, should be represented by a link which is separatefrom the link representing straight ahead traffic. One link may represent two or more lanes,

1 time varying traffic conditions can be modelled in TRANSYT


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provided that traffic is equally likely to join the queue in any of the lanes and that identical signalindications are shown to these lanes.

This link representation suggests that a detailed knowledge of traffic routing through a network is

necessary to prepare the link diagram. In practice, it is usually sufficient for the traffic engineer touse his judgement to decide whether traffic entering a section of road during a particular stagegreen chooses preferentially a particular direction on passing through the next signal and, if so, theproportions of various turning flows to assign to each link.

The relationship between lanes on the road and the way they are modelled as links is illustrated inFigure 3-1 and Figure 3-2. Figure 3-1 shows a simple ‘triangular’ road network. Figure 3-2shows the corresponding diagram of nodes and links. Traffic on the southern approach to Node 1is represented by two separate links because nearside turning traffic (link 13) receives a different

green time (because of a filter signal) to the other traffic (link 12) on the approach. On thenorthern approach to Node 3 traffic is also represented by two links (31 and 32). This gives amore realistic picture of traffic movements, since offside turning traffic from link 21 is unlikely to

turn right again at Node 3.

700

50350

600*

250

800

(J.T. = 30 sec)

(J.T. = 12 sec)

200700

300

650

50

400 100

N

J.T. =

*

Average journey time

All flow units in pcu/hour

All saturation. flows = 1800 pcu/hour

Figure 3-1 Network and flows

3.4

Flow, speed and link data

The TRANSYT model requires each link to be defined in terms of certain parameters. Those key

data values relating to the modelling of traffic behaviour are given here, and those concerned withsignal control are described in section 3.5 .


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Link length is the distance between the upstream and downstream stop lines. For links which donot come from an upstream node, e.g. entry Links on the perimeter of the network, it is normal touse a standard length such as 200m, but a zero value may be used.

700

50

600

350

400

350

22

300

350

(left filter)

450

50400

250

100

12

13

Intersection

or node

Link (No. 22)

2

22

11 221

3 33 700

3231

50 300

1

Figure 3-2 Diagram of links and nodes

3.4.1 Traffic flows

Link flows are specified in the Links Data screen ( Outline: Links/Link n/Link Flows). Flows arenormally specified in vehicles or PCUs per hour. For each link the user must specify the average

total flow along the link.

Each link may have associated with it a uniform flow source. This is a flow source which entersthe link at a uniform rate throughout the cycle. Thus, there is no platooning. It can be used torepresent, for example, uncontrolled flow from a car park. Links feeding into the network fromoutside also carry uniform flow but these flow levels are set using the Source Flow andassociated Total Flow for the link. The Uniform Flow Source is used only when there are otherupstream flow sources. The uniform flow source contributes along with the upstream sources togive the total flow, but need not sum exactly (see compatibility of link flows, section 3.4.3 ).

Each link can have up to six upstream links supplying it with vehicles. For each of theseupstream links the flow and the cruise time or cruise speed of vehicles along the link from theupstream source must be specified.


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3.4.2 Cruise times and cruise speeds

Cruise times and cruise speeds are the undelayed times (or speeds) for traffic travelling fromeach upstream stop line (for each source (upstream link)) to the stop line on the currently

selected link. The values used should be those which correspond to actual traffic behaviour andnot an ideal value intended to give good progression; they should represent the time taken totravel from upstream to downstream stop line, under prevailing traffic conditions, when the

signal aspects at both ends of the link are green. It is possibly better to measure cruise time (asopposed to cruise speed) because it ignores any error in link length measurement, and bymeasuring over the whole link it automatically takes into account skin-friction, curves,bottlenecks etc.

3.4.3 Compatibility of link entry and exit flows

The sum of inflows to a link need not equal the total flow. This facility is provided because in

practice the flow values will often be obtained from on-street measurements made at differenttimes. TRANSYT automatically increases or decreases by the same proportion all upstream flowvalues so that the total flow is maintained. If the proportional correction is large a message isprinted as a warning but the optimisation proceeds.

The calculation of the proportions of traffic leaving upstream links and entering downstream linksare made before the traffic modelling and signal optimisation calculations. If, in the trafficmodelling process, a link is oversaturated so that less traffic leaves than enters, then thedownstream volumes are reduced accordingly and the flows specified as the Total Flow will not

be maintained.

3.4.4

Saturation flow

Saturation flow at a stop line is the maximum rate of discharge from a queue. It can be obtainedby measurement or calculation based on stop line width and other site factors, for further detailssee RR67 (Kimber et al, 1986). The saturation flow must be in units consistent with those used inspecifying link flows.

If the saturation flow is reduced due to blocking of turning traffic by opposing traffic, then this maybe approximated by increasing the relative start displacement for the start of green on that link inthe Links Data Screen (Outline: Links/Link n/Link Signal Data/Green Period n) (see section 3.5 ), or

may be modelled more accurately using the give-way facility (see section 18.5 ).

3.4.5 Entry and exit links

For entry links on the perimeter of the network, having no upstream links but merely a total

flow, the user is recommended, in order to maintain a reasonable estimate of time spent withinthe network, to input a cruise time (or speed) for travel over the Length of link specified in theLinks Data screen (Outline: Links/Link n). No upstream link number or flow should be given.

Exit links are not required by TRANSYT but can be useful if the direction of traffic exiting the

network is to be shown graphically. As for entry links, in order to maintain a reasonableestimate of time spent within the network, a cruise time (or speed) associated with the traveltime along the link is required. If you wish the exit link to have no influence on either the signal

optimisation or on the queue and delay calculations the Link Data screen option “Exclude fromResults Calculation” can be set. This effectively ensures that the PI for the link is always zeroand that output results, such as the Network Totals, are not affected by it.


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3.4.6 Bottleneck links

Bottleneck links are treated as links with 100 per cent green at which a fixed saturation flow isdefined. A bottleneck link is treated in a similar way to other links – it still requires to be

associated with a traffic node (either a bottleneck node or priority node), but no signals node isspecified as it is not controlled by traffic signals.

Shared links which are bottlenecks are specified in the Links Data/Shared StopLines screen

(Outline: Links/Link n), as for signalised links, but the ‘main’ link still has only a traffic node andno signals node.

Delays and stops are calculated for bottleneck links exactly as for other links, except that the flowleaving the link is controlled only by the saturation flow. Thus, uniform delay and stops will occur

only if the flow during parts of the IN-profile exceed the saturation flow.Random-plus-oversaturation delay and stops are calculated in the normal way (see section 18.2).

3.5 Signal settings

NB for details of the actual implementation in TRANSYT 13, please see the section'Working with Traffic Signals' in this User Guide

3.5.1 TRANSYT signal terminology

TRANSYT models the operation of the signal control at each node by reference to stage changetimes. A stage change time is a time at which the green signal on one stage is terminated and the

change to the next stage green period is initiated; the next stage green usually commences a fewseconds later, following an interstage period. The green time displayed to traffic on any one linkmay be initiated by any stage change and terminated by any other stage change.

When considering co-ordination between signal-controlled intersections it is necessary to have aconvention which relates the green periods of any one junction to those at the other junctions inthe network. In TRANSYT this is achieved by relating all ‘stage change times’ to a common,although arbitrary, zero time as shown in Figure 3-3.

The offset of an intersection is defined here as the stage change time when the change to greenfor stage number 1 is initiated. In this way the offset may be thought of as the start of the cyclefor the node concerned, where the cycle commences with the change to stage 1 and continuesthrough the other stages in sequence.


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Green

Amber

D1 D2

Effective green displacement

at start of green

D =

Effective green displacement

at end of green

D =

Red/Amber

Green

Red

Red

Red Actual signal timings

Effective signal timingsRed

Figure 3-4 Effective versus actual signals

The global end displacement corrects for traffic continuing to flow during the amber-after-greenperiod as though the signal were effectively green. In the UK this value is typically 3 seconds

(equal to the full duration of the amber period). TRANSYT models traffic behaviour using effective

green periods which are typically 1 second longer than, and displaced relative to, the actual greensignal.

Additional relative displacements may be specified for individual links in theLink Signal Data. The displacements in the Main (Common) Data and therelative displacements in the Link n/Link Signal Data are added together in theprogram to give the effective green times before the queue calculations arecarried out.

However, all effective displacements are subtracted from the calculated greentimes before these are output in the results (see section 1) so that the trafficengineer can easily compare TRANSYT values with observations of actual greentimes.

Furthermore, a negative relative start displacement (say -2 seconds) could beused to justifiably remove or reduce the standard start displacement insituations where good coordination has resulted in the front of a platoon of

traffic arriving during a green signal.

3.5.3 Signal values for each stage

At each node, the user may specify data for up to 16 stages. These values are specified in the Signalised Nodes Data Screen (Outline: Nodes/Node n/Stages).


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The stage change times are specified in seconds. They are the times at which a change of signalaspect is initiated (for stage 1). Link green times are specified relative to these stage changetimes. When EQUISAT is being used no stage change times need be specified.

The interstage is specified in seconds. The interstage is defined as starting from the terminationof the first phase (or in TRANSYT, link) to lose green when a stage change is made (it alsosignals the end of the stage) to the commencement of the green for the last phase to receivegreen in the next stage.

The minimum green period (User Stage minimum) is the time between the interstage and theearliest time that this stage could end. This would normally be the minimum for the phase thatstarted last, unless this phase is an RTIA in which case it could be the minimum of one of theother phases.

The interstage time plus the minimum green period is a constraint used in green time and/or cycletime optimisation and by the EQUISAT routine, to prevent a stage having an unduly short green

time. A combined value in the range of 10 to 15 seconds is normal for vehicular traffic butpedestrian crossing needs may dictate longer times.

For a pedestrian stage, the minimum green period is the time from the end of the interstageperiod to the end of the green man indication (or the end of the black-out, if used) on thepedestrian stage. Since no traffic flows during the pedestrian stage, the pedestrian stage length

used by TRANSYT, after optimisation, is the interstage time plus the minimum green period .

3.5.4 Signal values for each link

These values are specified in the Links Data screen ( Outline: Links/Link n/Link Signal Data).

During one cycle a link may have one or, optionally, two, three or four green periods duringwhich outflow occurs. These green periods need not be the same length, but will have the samevalue of saturation flow.

Links may receive green for all or part of one or more stages. The time at which the actualgreen begins is specified by a start stage number and a start lag of a fixed number of seconds.Similarly, the time at which green ends is specified by an end stage number , and the effectivegreen can be extended by use of a relative end displacement .

The link start stage number defines which of the stage change times starts the change to thegreen period on the link. The start lag then gives the time in seconds from the stage changetime to the start of green signal on the link. Usually the start lag corresponds to the interstage

time, as shown in Figure 3-5 . TRANSYT adds the displacement of start of effective green (seeFigure 3-4) to this lag to give the time of start of traffic flow assumed in calculating delays etcfor the link.

The displacement of start of effective green is the sum of the global startdisplacement and relative start displacements


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If it is thought that the effective start-green displacement for the link differs from the overallvalue given by the global network Start Displacement , this can be represented by adding arelative start displacement . For example, if the global network displacement (see section 12.7 )

is 2 seconds, and it is known that, for the link considered, the effective green displacement is

one second longer than the overall value, then the required relative start displacement issimply 1 second.

Amber

Red

Red/Amber

GreenGreen

RedGreenRed Red

Start

LagStart

Lag

Start green on

stage 2

Start green onstage 1

Demand

change to

stage 2

Demand

change to

stage 1

Stage 1 actual signals

Stage 2 actual signals

Figure 3-5 Lag between change demand and start of green signal

The link end stage number defines which stage change time ends the green period on the link.The green periods can run between any stage numbers, e.g. 2 to 3, 2 to 6, 7 to 3, or 4 to 4(in the latter case, the green period will be of fixed length).

Following the end stage, is the end lag, defining the time in seconds from the stage change time to

the end of green signal on that link. The same considerations apply as for the start green lagregarding any extra adjustments. Normally this value is zero.

Should the link have a second green, the corresponding values detailed above for the first green

must be specified for the second one.

3.6 Traffic behaviour within a link

TRANSYT makes use of one of two traffic models. These are the platoon dispersion model (PDM)and the Cell Transmission Model (CTM). The two models each have their own advantages anddisadvantages. The CTM is particularly useful for small networks with short links. Its main

advantage is its ability to model the effects of traffic blocking back from one junction to another

reducing the upstream junction’s capacity. The PDM model is suited to all network types and hasthe advantage of being able to model the dispersion of platoons of traffic along links, but does not


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model the effects of blocking back. Full details on both models are given in chapter 1 and on cyclicflow profiles in Section 13.4 including advice on choosing the right model to use.

To model traffic behaviour within the network using either model, the common cycle time is

divided into a number of intervals called steps. For convenience, a step is typically set to be onesecond long. How these ‘steps’ are used depends on the model used.

With the PDM model TRANSYT’s calculations are made on the basis of the average values of trafficdemand and queues for each step of a typical cycle. The resultant histograms of traffic arrivals

per step are termed cyclic flow profiles.

The profile of traffic entering a link will be displaced in time and modified during the journey alongthe link due to the different speeds of the individual vehicles. Thus, platoons of vehicles will bepartly dispersed. The amount of dispersion can be modified for individual links.

By selecting the PDM model, TRANSYT automatically takes into account the importance of having

good progression on short links.

The CTM model also uses ‘steps’ but is it also discrete in space as well as in time. As a result the

CTM cyclic flow profiles are different and are differently presented. The representation of traffic istherefore different to the PDM model.

Both models use a simplification of real traffic behaviour, and do not model individual vehicles.Despite this, TRANSYT is able to predict good estimation of traffic delay.

Full details of the data required for both models are given in section 7 .

3.7

Delays, Queues and Stops

Total delay to traffic on a link is the sum of the delays to all the individual vehicles using the linkduring a period of time. Total delays are usually quoted in units of PCU-hours/hour. Forexample, during a cycle of 100 seconds, 40 PCUs pass through a signal. On average they

experience 20 seconds of delay each. Thus, the total delay rate is 800 PCU-seconds per 100second cycle (equivalent to 8 PCU-seconds/second or 8 PCU-hours/hour). This delay rate isequal to 8 PCU and can be visualised as the average number of PCUs queueing throughout thecycle considered. This is strictly true only for the idealised vehicle behaviour that is assumed in

TRANSYT. Nevertheless, this interpretation is a reasonable approximation to what happens inreality. Similarly, the total delay rate in a network of signals can be considered as the sum ofthe average queues at all the stop lines. In TRANSYT, the total delay rate for traffic on a link is

obtained partly from the cyclic flow profiles and partly using a simple formula.

When considering the growth and decay of queues, the fact that individual vehicles arrive atrandom, and that average arrival rates may vary over the modelled period, means the accuratemodelling of queues is complicated. The problem was studied comprehensively by TRRL (Kimber

and Hollis, 1979) and a time dependent method of predicting queues and delays was developed.The method considers the probability distribution of queue lengths as a function of time.

Queue lengths are derived from cyclic flow profiles during each step of the typical cycle. As well asthis ‘uniform’ component of queue, additional elements associated with random and oversaturatedeffects are added to these. Full details of queue length derivation are described in Section 18.2.1.

TRANSYT also calculates the total rate at which vehicles are forced to stop on a link. This too, ismade up of a ‘uniform’ component and a ‘random-plus-oversaturation’ component. As for delay,


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the uniform component is obtained from the cyclic flow profiles and therandom-plus-oversaturation component is calculated from simple equations.

3.8

Maximum queues

As part of the calculation of traffic behaviour on a link, TRANSYT estimates the maximum queuelength to be expected with the given signal settings. In reality, on some links, particularly short

ones, the queue may reach back from one junction to another, thereby at least partially blockingthe upstream junction. This complex effect is, however, not modelled in TRANSYT’s platoondispersion model (PDM) which assumes that all vehicles queue at the stop line. TRANSYT doeshowever include a facility whereby the user can specify a limit queue for selected links. The signaloptimiser then attempts to find settings which make it less likely that the maximum queues willexceed the limit values (see section 19.4) Furthermore, the new Cell Transmission Model (CTM)does model blocking back effects, which can be used instead of the PDM model in certain

circumstances.

3.8.1 Mean maximum queue

TRANSYT computes a mean maximum queue (PCU); this value is estimated from twocomponents as follows. During the typical cycle (see chapter 1) modelled in TRANSYT, a checkis kept on the position of vehicles adding onto a queue (measured in numbers of PCU back fromthe stop line rather than in distance units). During a green period, traffic discharges from thefront of the queue but further traffic may join the back of the queue. The ‘maximum back of

queue’ is the position (in PCU) reached by the back of the queue just as the queue empties (seeFigure 3-6). This value is an average obtained assuming that arrivals each cycle are identical tothat modelled during the typical cycle and is known as UMMQ, uniform component of the MMQ.The second component is the average random-plus-oversaturation queue (numerically equal tothe random-plus-oversaturation delay on the link), which is added to the maximum back ofqueue to give the value printed out.


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0 4 8 12 16

4 5 6 7 8

4 3 2 1 0

time

Arrival rate = 1 pcu / 4 seconds

Departure rate = 1 pcu / 2 seconds

Max. back of queue

Queue

Queueing vehicle

Vacated space

Stop line

Figure 3-6 Uniform Component of Mean Maximum Queue

The second component is a correction to the maximum back of queue value which makes someallowance for variations in queue size from cycle to cycle. It may be thought of as the average number of vehicles which fail to discharge at the end of the cycle, although, in reality, this may

be zero or a larger number during individual cycles.

The mean maximum queue (PCU) is only an approximate average of the maximum queues likely

to be encountered, and it will therefore be exceeded 50 per cent of the time.


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3.9 Give-way situations

In urban road networks there are usually a number of priority junctions. If significant, theseshould be modelled.

In TRANSYT there are two types of priority situations that may need to be modelled. The firstsituation is a give-way junction (priority intersection) located somewhere between the signal

controlled junctions. This includes unsignalised approaches to partially signalised roundabouts.

The other situation occurs within a signal-controlled junction i.e. traffic on a link which, althoughsignal-controlled, must also give way to an opposing flow. Such situations occur frequently atsignalled junctions where traffic turns right without a separate signal indication.

In both situations TRANSYT is able to take account of the varying opposing (controlling) trafficconditions that the opposed (give-way) traffic has to yield to, and calculate the required queue,delay and stop information.

Additionally, when using the CTM traffic model, congested give-way situations can also be takenaccount of.

Full details on how to model both give-way situations are in section 18.5

3.10 Shared stop lines

Normally no distinction is made in TRANSYT between the various types of vehicles on a link. The

use of shared stop lines allows separate classes of vehicles to be represented in any one queueingsituation where, in reality, the classes of vehicles are mixed together, i.e. in a ‘common queue’.One reason for this separation of vehicle types is because the vehicles exhibit different behavioursuch as buses which may stop at bus- stops along the link.

Furthermore, the vehicle ‘types’ need not be different types of vehicles but may consist of vehicleswhich, for example, entered from different roads at the upstream intersection. This facility hasproved particularly useful when modelling signalised roundabouts (see AG48, Chapter 11).

Full details of shared stop lines are given in section 18.6.

The user of the program must decide how many classes of vehicles are necessary to represent the

conditions being studied. Each class of vehicle at a common stop line is represented by a separatelink. For vehicles in a given class at the shared stop line, TRANSYT calculates the delay for thatclass taking into account delay caused by the interaction between all vehicles using the shared

stop line.

Shared stop lines can be applied to both signalled links and give-ways.


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3.11 Flared Approaches

TRANSYT provides a facility to model the extra capacity available from flared approaches givingan extra lane or lanes at the stop line. The non-linear saturation flow is of the stepped formshown in Figure 3-7 . It contrasts with the constant, single valued, saturation flow for non-flared links.

0 green time

sat.flow

Figure 3-7 S tepped saturation flow of a flared link

For further details on modelling flares see section 18.7 . This includes examples of the variouscases where flares are used. Data-entry requirements are detailed in section 8.5 .


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Optimisation Basics Page 37


4 Optimisation Basics

This is only a brief overview of the TRANSYT optimiser. Existing users of TRANSYT can probably

skip this chapter. Details have been kept to a minimum in order to keep the emphasis ongetting to know how to use TRANSYT quickly, providing just enough background prior to usingTRANSYT. However, TRANSYT is a complex program, so there are references to other chapters.These chapters will still need to be read in order to know how to use all the optimisation facilitiescorrectly.

4.1

Network timings optimisation

The optimisation process searches for a set of timings for the network which minimise queues and

delays by altering both the signal offsets, which affect the co-ordination between signals, and thedurations of the individual stage green times at each junction (i.e. green splits).

It works by applying a cost to the amount of delays, stops and excess queues on each link which issummed to provide an overall cost of the network for a particular set of timings. These timingsare then manipulated bit-by-bit in search of timings giving a lower overall cost. The processemployed is called ‘hill-climbing’ – because the set of solutions, if plotted, could be thought of as aseries of hills and valleys in a multiple-dimensional world. The solution found will be at the bottom

of one of the valleys. Full details of the calculation of Performance Index (P.I.) and the hill-climbing process are explained in chapter 1.

Before optimisation, TRANSYT must have a starting Performance Index calculated from an initialset of signal timings. A feature called EQUISAT (Equalisation of saturation) removes the need for

the user to provide these initial timings.

The nodes which are to be optimised are listed in the Node Number List for Hill-climb Data(Outline: Network Options/Node Optimisation Order ). If a node is omitted from the list its initial

settings will not be altered. Thus, a network can be studied in which one or more nodes within thenetwork do not have their initial settings altered and act as a constraint on the optimisation of theremaining nodes.

Furthermore, optimisation can be switched off so that TRANSYT can simply run an existing set of

timings in order to evaluate the performance of the network for these timings.

4.2

Cycle Time optimisationCycle time is not automatically considered by the signal optimiser, but TRANSYT’s “Cycle TimeOptimiser” tool (which incorporates CYOP), can be used to evaluate a range of cycle times, fromwhich the optimum can be selected. The operation of, and output from the Cycle Time Optimiser

and CYOP are described in section 19.7 which also discusses issues related to the choice of cycletime.


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TRANSYT 13 Input Data Page 39


5 How to use TRANSYT 13

5.1

Essential GUI terms you need to know

To ensure a full understanding of how the graphical interface works it is useful to be familiar witha few terms that are familiar to TRANSYT 13. Please spend a few moments reading theintroductory section of the Glossary. (TRANSYT 13 GUI Terms).

5.2

Quick start for TRANSYT users

Note: the following is only a very brief overview. See General Graphical User Interface (GUI)

operation for a general description of the GUI and details of the menus and toolbar buttons. For

details of further program functionality please browse through the rest of this User Guide.

There is no fixed route through TRANSYT 13, and as such it offers a high degree of flexibilitywhen creating a new network. In general, data can be entered in any order and changed at anytime: the graphical user interface (GUI) is highly dynamic and any dependent data and screensare automatically updated.

If you are a new user, the open-ended nature of the TRANSYT 13 GUI may leave you wondering

where to start… so the below is one suggested way to build a new file. Please note that this isonly a suggestion, and with experience, you will find your own preferences and may well findyourself building files in a completely different order.

If in doubt, the Task List (see Task List ) always shows any current problems with thefile. For example, if you show the Task List immediately after starting a brand new file, it willshow a list of errors and warnings similar to the screenshot below, which should give you an ideaof what needs to be done. Double clicking on a row in the Task List will often take you to an

appropriate screen.

When the program first starts, or you click File>New , a skeleton file is created that contains avery simple network consisting of a single node and two links. (You can if you wish run this fileand generate results.) To start building a network, you should use this skeleton network as astarting point.


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Use the Data Outline (Data Outline) and the toolbar icons to access each data area and performoperations. Although the Data Outline can be used to enter most data it will often be easiest to

use the Network Construction Editor (Netcon) to build your network of nodes and links and thenpopulate these with the required data. If you make a mistake at any point, use the Undo/Redobuttons.

Therefore, assuming the use of NetCon, a suggested order of data entry is as follows:

1. In the File Description Area (via the Data Outline and Data Editor), Enter the project title,location etc, and set the driving side.

Network: nodes and links

2. Add all nodes, renumbering them and locating them into their approximate position asrequired. (Node 1 is always present and cannot be deleted, but you may need to renameit. Similarly, you cannot delete Link 1.) You can add signalised, priority and bottlenecknodes by using the appropriate toolbox tools.

3. Add all links, locating them in the appropriate location between the relevant nodes as youcreate them. To set the link type (e.g. normal, give-way, pedestrian etc), you can eitheruse the appropriate toolbox tool, or, you can right-click on the link after adding it and then

set the type.


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4. Attach each link to its controlling node by using the connector tool in NetCon. This tells

TRANSYT which node controls the traffic and, for signalised links, which node controls the

signals. (These can be set up separately if required.) These associations are shown withthe blue cones; moving each node will now move all attached links as well.

5. Attach each link to its downstream link(s) by using the connector tool in NetCon.


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6. Set up any shared stop lines by using the shared stop line tool in NetCon.

7. Double click on links and use the Data Outline and Data Editor to set up any requiredproperties such as give-way properties, lengths, saturation flows and so on.

At this point the Task List will still show a large number of errors but these should all be todo with signals rather than network connectivity.

8. ALTERNATIVE: As an alternative to using the Data Outline and Data Editor, you can usethe Links and Nodes screens, which show all common data in an easily accessible format.

9. ALTERNATIVE: Use one or more Data Grid screens to rapidly enter data for all nodesand/or links in one go. This saves having to click on each link in turn, especially if youhave all data to hand in a tabular form.

Traffic Flows

10. You can enter traffic flows and set up cruise times etc by clicking on each link and source inNetCon and then entering the appropriate numbers in the Data Editor. (‘Sources’ werereferred to as ‘upstreams’ in TRANSYT 12). Click on a link to view and edit its main flowand uniform flow; click on a connector between links to set up the flows between links.


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11. ALTERNATIVE: Use the Links Data screen to view and edit all flows and sources for each

link.

12. ALTERNATIVE: Use one or more Data Grids to view and edit for all flows for all links (andsimilarly for all sources).

TIP: Use the Link Flows Consistency Diagram to check the consistency of flows entering andleaving each link.


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SignalsTRANSYT 13 has two signals representation modes: TRANSYT 12 Mode and TRANSYT 13 Mode.

The default is TRANSYT 12 Mode, and the mode can be changed at any time by clicking

Tools>Signals and then choosing a mode. There are various ways of entering signals data:some suggested methods are given below for both modes. In TRANSYT 13 mode, you canmanipulate stages in a more graphical way by manipulating a diagram screen; in TRANSYT 12

mode, you must add and manipulate items in a more numerical and tabular format.

TRANSYT 12 Signals Mode

13. Use the Nodes Data screen to add the necessary number of stages for each node. (Or usethe Data Outline.) Enter the stage start times and preceding interstages, etc, usingTRANSYT 12 notation.

14. For each signalised node, use the Stage Sequence screen to set which links run during eachstage, and use the Link Timings screen to confirm this visually. Use the Nodes Data screenand the Link Data screen (or the Data Outline/Data Editor) to add/delete stages/greenperiods and enter start/end lags, etc.

TRANSYT 13 Signals Mode

15. Double-click on a node in NetCon to display the Link Timings screen for that node. Withinthe Link Timings screen, click Tools>Reset and Create New Stages and enter the number ofrequired stages. This will add the stages with arbitrary timings.


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16. ALTERNATIVE: Right-click on each item in the Link Timings screen (stages and greenperiods) and use the pop-up menu to add/delete stages and green periods.

17. Set initial link green times by dragging stages and green periods with the mouse within theLink Timings screen. (Select Behaviour>Allow redefinition…).

18. If you prefer, use the Stage Sequence screen to set up stages.

19. If required, enter link intergreens, using the Link Intergreen screen. This adds constraintsto the signals optimiser.

20. Double click on each item in the Link Timings screen (stages and green periods) and setany necessary properties such as minimum green times.

Network properties (NB you may prefer to set these at the beginning)

21. Use the Main Data screen (or the Data Outline) to select an initial network cycle time,optimiser options (see chapter 1), whether to use EQUISAT and the traffic model to use(PDM or CTM). If you would like to generate CTM cell data that can be used to show cell


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occupancy animations, select Generate CTM Cell Data. (There are certain restrictionsplaced on the use of the CTM.)

Running the file and inspecting results

22. Save the file and then press the Run button. If there are any errors in the data file, youwill be directed to the Task List to try to fix those errors before running the file. Otherwise,

TRANSYT will start to run and the Running Calculation screen will keep you informed ofprogress by showing a status bar and the best P.I. found so far. Note: For small networksand un-optimised runs, this screen may only appear for the briefest of moments. Using theStop button will stop the calculations and produce results for the best P.I. discovered so

far.

23. On completing the calculations the Summary Results screen will appear. This provides asummary of the network operation, given the network flows, current options and optimised

signal timings (unless the Optimisation Level = “None” - ‘evaluation mode’ in effect). TheNetwork PI (Performance Index) provides an index, in monetary terms, of the entirenetwork.

24. Inspect network results by locating Network Results in the Data Outline and thenexpanding the relevant section.


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25. Inspect individual link results by expanding the Results section of each link in the DataOutline.

26. Inspect collections of link results with the Data Grid screen.

27. Generate CFP, Queue and CTM graphs using the Graphs button.

28. Generate a report that summarises all input and output data by clicking the Run Report

button.

29. View the optimised signal timings via the Link Timings screen.

30. View animations of signals, link effective greens, queues and cell occupancies in NetCon by

showing the Animation Controls screen and then selecting from various options withinNetCon.


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31. Generate Time Distance Diagrams using the Graphs button, in order to observecoordination along links.


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If you cannot find an answer to your question, check the TRL software website for latest news orcontact us directly at TRL.

6.3

Accessibility

A program such as TRANSYT inevitably has to use colours such as red and green to representdifferent signal states. In recognition of the fact that some users may prefer to use a different

colour scheme, and to make black and white printing more flexible, most of the colours used inTRANSYT 13 can be customised via the Preferences screen. Select File>Preferences, and thenadjust the options in the Colours section.

6.4 Demo (and Viewer) mode

TRANSYT 13 may be provided to you in a demonstration mode. In this mode, most of thefunctionality of the program is present but there are a number of restrictions in place: forexample, you cannot save or run files. To remove these restrictions, you must upgrade to the

full version of the software by purchasing an unlock key from TRL, which can then be entered onthe screen displayed when the program first starts. See Installing the Software for more details.

If you have obtained an evaluation version of the software, this will run in unrestricted mode fora certain number of days, and then revert to demo mode. You must then purchase an unlock

key as above to unlock the full version of the software.

The current security status of the program is shown in the splash screen, which is available fromwithin the program by selecting Help>About.

Because TRANSYT 13 files include results from running the program, the demoversion of TRANSYT 13 can be used by anyone to view both the input and outputfrom TRANSYT 13 files. This includes animations and graphs, as long as the filewas saved using the File>Save With Full Run Data option.


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6.6 Main toolbars

6.6.1 Main Menu

The options within the main menu (File, Edit, View, Go To, Run, Tools, Options, Help) mostlyduplicate the buttons on the main horizontal and vertical toolbars, and are self-explanatory.

Some TRANSYT 13 features however are only available from the menus, such asimporting/exporting options. The View and Go To menus, in particular, are useful as a short-cutto the various items within the Data Outline. Please explore the options in the menus and referto this User Guide for full details.

6.6.2 The 'Go To' menu

This menu gives easy access to common data items and takes you to the first item of theappropriate kind in the Data Outline and Data Editor. It does NOT open any other specific

screens – use the View menu or the toolbar icons for this.

Use the Go To Node… and Go To Link… options to go straight to a specific node/link if you knowthe ID of the node/link.

6.6.3 Horizontal toolbar

From left to right, the buttons on the horizontal toolbar are:

Icon User guide reference

New File

Managing filesOpen File

Save File

Copy to clipboardClipboard

Paste

UndoUndo/redoRedo

Show Data Outline Data outline

Show Data Editor Data editor

Show Data Grid Data grids

Show Task List Task list

Back

Changing the active data itemForwards

Previous

Next

Toggle Auto-RunRunning filesRun File

Generate Report Reports


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6.6.4

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Documents