School of Civil and Environmental Engineering Term 2, 2019 CVEN3031 CIVIL AND ENVIRONMENTAL ENGINEERING PRACTICE Assignment 1: (50 Marks) Deadline: 5pm, Friday, the 14th of June (Week 2) Maximum 3 pages excluding references and appendix. 1) For the network provided in the group project brief (Figure 1): i) Write down the “appropriate” names of the centroids, based on the suburb(s) they represent (and from where the traffic can potentially originate, terminate, and pass through). A couple of examples are provided in Table 1. (5 Marks) ii) If the total percentage of vehicles (assume cars only) entering and exiting the network from all the centroids during the morning peak hour, i.e. 8am to 9am is 100 and 100 respectively, what “could” be the percentage of the total demand that is generated and attracted by each centroid in the network? State your assumptions. Present your answer in a tabular format (refer to Table 1). The proportions need not be entirely accurate but should be well supported by your assumptions based on the land use characteristics1, and personal observations of the study area. (30 Marks) Table 1 List of Centroids S.No. Centroid Name 1 2 3 4 5 6 7 SUM 1 2 3 4 5 6 7 ? ? ? City and beyond Kensington, Zetland, Waterloo, and beyond ? ? Percentage of Total Trip Generation ? ? ? ? ? ? ? 100 Percentage of Total Trip Attraction ? ? ? ? ? ? ? 100 An important aspect of planning for a new development is to predict the amount of generated and attracted traffic. This is a necessary input for transport planning, traffic infrastructure design and management. Understanding the land use characteristics such as population density, the presence of local services and facilities, socio-economic characteristics, availability of residential parking, etc. is very helpful to estimate the number of trips generated and attracted by a suburb. Refer to Section 5.1 of the RMS modelling guidelines document for more details. 1 1 Figure 1 Model network for the group project 2) Make use of the Aimsun manuals to answer the following questions. Show your understanding. Do not merely reproduce from the manuals. (15 Marks) i) What is the warm-up period, and what purpose does it serve? ii) What is the difference between the two models “Fixed using the travel time calculated at the end of the warm-up period” and “C-logit” (specified in Dynamic Scenario -> Micro SRC Experiment -> Dynamic Traffic Assignment -> Stochastic Route Choice)? iii) In the C-logit model, what do the parameters Scale, Beta, and Gamma mean? iv) What is the purpose of the cycle and number of intervals (specified in Dynamic Scenario -> Micro SRC Experiment -> Dynamic Traffic Assignment -> Costs)? v) What is a “yellow box” intersection? vi) What is a red percentage (specified by right-clicking on a Node -> Edit Control Plan)? PLAGIARISM Beware! An assignment that includes plagiarised material will receive a 0% Fail, and students who plagiarise may fail the course. Students who plagiarise are also liable to disciplinary action, including exclusion from enrolment. Plagiarism is the use of another person’s work or ideas as if they were your own. When it is necessary or desirable to use other people’s material you should adequately acknowledge whose words or ideas they are and where you found them (giving the complete reference details, including page number(s)). The Learning Centre provides further information on what constitutes Plagiarism at: https://student.unsw.edu.au/plagiarism 2 Aimsun 8 Dynamic Simulators Users’ Manual July 2014 © 1997-2014 TSS-Transport Simulation Systems About this Manual The present manual describes the use of the Microscopic, Mesoscopic and Hybrid simulators in Aimsun 8. The microscopic simulator is available in the following Aimsun editions: Aimsun Small, Aimsun Standard, Aimsun Professional for Micro, Aimsun Advanced and Aimsun Expert. The mesoscopic simulator requires a license of Aimsun Professional for Meso, Aimsun Advanced or Aimsun Expert. The hybrid simulator requires a licence of Aimsun Advanced or Aimsun Expert to be used. It also describes the use of the embedded pedestrian simulator Legion in a microscopic simulation. The Legion for Aimsun module requires a Legion for Aimsun licence that is included in all Aimsun editions. Note that, Legion is only available for the Windows versions (both 32bit and 64bit). Our aim is to keep you informed of any changes so that you can continue to get the best from Aimsun. As always, please be aware that product data is subject to change without notice. Features labelled 'Fast Track' have been added after the Aimsun 8 Final Release and they are only available to users in possession of a valid SUS. TSS-Transport Simulation Systems has made every effort to ensure that all the information contained within this manual is as accurate as possible. It should be stressed however, that this is a draft version of the latest Aimsun Dynamic Simulators User’s Manual and as such, some of the contents may be subject to change. As always, we welcome your feedback (support@aimsun.com) in our continued improvement and addition of new features to Aimsun. 1.1 Copyright Copyright  1997-2014 TSS-Transport Simulation Systems, S.L. All rights reserved. TSS-Transport Simulation Systems products contain certain trade secrets and confidential and proprietary information of TSS-Transport Simulation Systems. Use of this copyright notice is precautionary and does not imply publication or disclosure. 1.2 Trademark Aimsun is trademark of TSS-Transport Simulation Systems. S.L. Other brand or product names are trademarks or registered trademarks of their respective holders. Draft 2 1.1 1.2 1 COPYRIGHT ........................................................................................... 2 TRADEMARK .......................................................................................... 2 INTRODUCTION ........................................................................................ 17 1.1 MICROSIMULATOR, MESOSIMULATOR, HYBRID SIMULATOR AND AIMSUN .............................. 18 1.2 INPUT DATA REQUIREMENTS ........................................................................ 19 1.2.1 Network Layout ............................................................................. 19 1.2.2 Traffic Demand Data ....................................................................... 20 1.2.3 Traffic Control .............................................................................. 20 1.2.4 Public Transport ............................................................................ 21 1.2.5 Initial State .................................................................................. 21 1.3 NOTE ON UNITS .................................................................................... 23 2 TRAFFIC MODELLING ................................................................................. 25 2.1 TRAFFIC DEMAND DATA............................................................................. 25 2.1.1 Vehicle Classification ...................................................................... 25 2.1.2 Input Flows and Turning Proportions .................................................... 26 2.1.3 O/D matrices ................................................................................ 27 2.1.4 Traffic Arrivals .............................................................................. 27 2.2 TRAFFIC GENERATION .............................................................................. 31 2.2.1 Exponential .................................................................................. 31 2.2.2 Uniform ....................................................................................... 31 2.2.3 Normal ........................................................................................ 32 2.2.4 Constant ...................................................................................... 33 2.2.5 “ASAP” ........................................................................................ 33 2.2.6 External ....................................................................................... 34 2.2.7 Summary of Generation ................................................................... 34 2.2.8 Dealing with a fractional number of trips ............................................. 34 2.3 VEHICLE ENTRANCE PROCESS ....................................................................... 37 2.4 VEHICLE MODELLING PARAMETERS .................................................................. 37 2.4.1 Vehicle Attributes .......................................................................... 38 2.4.2 Local Parameters ........................................................................... 51 2.5 VALID TARGET LANES MODEL: DYNAMIC LOOK-AHEAD ............................................... 59 3 TRAFFIC CONTROL MODELLING ................................................................... 65 3.1 TRAFFIC SIGNAL CONTROL.......................................................................... 65 3.1.1 Signal Groups and Phases .................................................................. 65 4 RAMP METERS ......................................................................................... 68 4.1.1 4.1.2 4.1.3 4.1.4 4.1.5 5 Green Time Metering ...................................................................... 69 Green Time by Lane Metering ............................................................ 69 Flow Metering ............................................................................... 71 Delay Metering .............................................................................. 73 Flow-ALINEA Metering ..................................................................... 74 ACTUATED CONTROL ................................................................................ 76 5.1 ACTUATED PARAMETERS ............................................................................ 77 5.2 DETECTORS PARAMETERS ........................................................................... 79 5.3 COORDINATED PARAMETERS ........................................................................ 80 5.4 MULTI-RING CONTROLLER .......................................................................... 80 5.5 ACTUATED CONTROL DEFINITION .................................................................... 81 5.5.1 General parameters ........................................................................ 81 5.5.2 Rings and barriers editing ................................................................. 82 5.5.3 Phases definition ............................................................................ 82 5.5.4 Graphical Phase Diagram .................................................................. 88 6 PRE-EMPTION .......................................................................................... 90 Draft 3 6.1 7 GIVE WAY AND STOP SIGNS......................................................................... 93 7.1 7.2 8 PRE-EMPTION PARAMETERS ......................................................................... 90 GIVE WAY PRIORITY DEFINITION .................................................................... 94 STOP LINES FOR TURNINGS WITH A YIELD SIGN ...................................................... 94 LEGION FOR AIMSUN ................................................................................. 95 8.1 INTRODUCTION ..................................................................................... 95 8.2 PEDESTRIAN TYPES.................................................................................. 95 8.2.1 Create new pedestrian types ............................................................. 95 8.2.2 Change pedestrian type settings ......................................................... 96 8.2.3 Choose how pedestrians are visualised ................................................. 98 8.3 PEDESTRIAN CROSSINGS ............................................................................. 99 8.3.1 Create a new pedestrian crossing for a node .......................................... 99 8.3.2 Change the length of a pedestrian crossing ........................................... 99 8.3.3 Control pedestrian movement at crossings ............................................ 99 8.3.4 Signal groups ................................................................................ 100 8.4 PEDESTRIAN NAVIGATION AREAS ................................................................... 100 8.4.1 Define where pedestrians can go ....................................................... 100 8.4.2 Define where pedestrians cannot go ................................................... 101 8.5 PEDESTRIAN CENTROIDS............................................................................ 109 8.5.1 Create a pedestrian centroid configuration .......................................... 110 8.5.2 Pedestrian entrance centroids .......................................................... 110 8.5.3 Pedestrian exit centroids ................................................................. 111 8.6 ROUTES AND DEMAND .............................................................................. 112 8.6.1 Pedestrian O/D routes .................................................................... 112 8.6.2 Define pedestrian trips with a pedestrian O/D matrix ............................. 119 8.7 PUBLIC TRANSPORT................................................................................ 121 8.7.1 Public Transport Stops .................................................................... 121 8.7.2 Timetable editing .......................................................................... 123 8.7.3 Vehicle Attributes ......................................................................... 124 8.7.4 O/D matrix editing ........................................................................ 126 8.7.5 O/D route editing .......................................................................... 126 8.8 SIMULATION ....................................................................................... 126 8.8.1 Legion extension activation .............................................................. 127 8.8.1 Automatic build option ................................................................... 130 8.8.2 ORA file ...................................................................................... 131 8.9 LEGION OUTPUTS.................................................................................. 133 8.9.1 Replication outputs ........................................................................ 134 8.9.2 Section outputs ............................................................................. 134 8.9.3 O/D Pair outputs ........................................................................... 135 8.9.4 Service Point outputs ..................................................................... 136 8.9.5 Public Transport Stop outputs ........................................................... 136 8.9.6 Database outputs .......................................................................... 136 8.10 LEGION LICENCE ................................................................................... 139 9 RUNNING THE SIMULATION ....................................................................... 141 9.1 AIMSUN SCENARIO ................................................................................. 141 9.1.1 Main Folder ................................................................................. 142 9.1.2 Output Folder .............................................................................. 143 9.1.3 Aimsun API Folder ......................................................................... 156 9.1.4 Variables Folder ............................................................................ 157 9.1.5 Strategies & Conditions Folder .......................................................... 157 9.1.6 Parameters Folder ......................................................................... 158 9.1.7 Scenario's Context Menu .................................................................. 158 9.2 AIMSUN DYNAMIC EXPERIMENT ..................................................................... 158 9.2.1 Main Folder ................................................................................. 159 9.2.2 Behaviour and Reaction Times folder .................................................. 162 9.2.3 Arrivals Folder .............................................................................. 162 9.2.4 Dynamic Traffic Assignment Folder .................................................... 164 Draft 4 9.2.5 Variables Folder ............................................................................ 166 9.2.6 Policies Folder .............................................................................. 167 9.2.7 Dynamic Experiment's Context Menu ................................................... 167 9.3 AIMSUN REPLICATION .............................................................................. 168 9.3.1 Replication Editor ......................................................................... 169 9.3.2 Replication Context Menu ................................................................ 171 9.4 AIMSUN AVERAGE .................................................................................. 173 9.4.1 Average Context Menu .................................................................... 175 9.5 AIMSUN RESULT ................................................................................... 176 9.6 SIMULATING AN ANIMATED REPLICATION ........................................................... 176 9.7 RECORDING A REPLICATION ........................................................................ 178 9.8 SIMULATING A BATCH REPLICATION ................................................................ 179 9.9 SIMULATING A RESULT ............................................................................. 179 9.10 VARIABLES ......................................................................................... 180 10 TRAFFIC MANAGEMENT ........................................................................... 182 10.1.1 10.1.2 10.1.3 10.1.4 10.1.5 10.1.6 10.1.7 10.1.8 11 Strategies.................................................................................... 182 Policies ....................................................................................... 183 Triggers ...................................................................................... 185 Actions ....................................................................................... 186 Authorities .................................................................................. 197 Problems ..................................................................................... 197 VMS ........................................................................................... 197 Traffic Conditions.......................................................................... 198 SIMULATION OUTPUTS ............................................................................ 201 11.1 ANIMATED OUTPUTS ............................................................................... 201 11.1.1 Animation of the simulation ............................................................. 201 11.1.2 Simulation Attributes in Objects ....................................................... 202 11.1.3 Default View Styles and Modes in the simulation ................................... 204 11.1.4 Displaying Vehicle Attributes ............................................................ 205 11.1.5 Displaying Simulated Traffic Control .................................................. 209 11.1.6 Space Time Diagram ....................................................................... 214 11.1.7 Analyser Dynamic Label .................................................................. 218 11.2 BATCH OUTPUTS .................................................................................. 220 11.3 GROUPED OUTPUTS ............................................................................... 220 11.3.1 Statistics by Grouping ..................................................................... 220 11.4 VEHICLE DETAILS EXPORTATION ................................................................... 221 11.4.1 FZP Exporter ................................................................................ 221 11.5 TIME SERIES VISUALIZATION ....................................................................... 224 11.5.1 Time Series Comparison .................................................................. 226 11.6 OUTPUT COMPARISON ............................................................................. 227 11.6.1 Hypothesis Test Comparison ............................................................. 228 11.6.2 Regression ................................................................................... 230 11.6.3 Decision Table Comparison ............................................................... 231 11.7 STORING SIMULATION RESULTS USING ODBC ...................................................... 231 11.7.1 Output Location ............................................................................ 232 11.7.2 Creating a Data Source ................................................................... 232 11.8 REVISIONS ......................................................................................... 234 12 DYNAMIC TRAVERSAL GENERATION ............................................................ 236 13 CALIBRATION AND VALIDATION OF AIMSUN MODELS ....................................... 238 13.1 METHODOLOGY FOR BUILDING SIMULATION MODELS ............................................... 238 13.2 THE VALIDATION PROCESS: BUILDING VALID AND CREDIBLE SIMULATION MODELS .................. 241 13.3 SPECIFICS FOR THE VALIDATION OF TRAFFIC SIMULATION MODELS ................................. 245 13.3.1 Develop a traffic simulation model with high face validity with Aimsun ....... 245 13.3.2 Test the assumptions of the model empirically ...................................... 248 13.3.3 Microsimulator Network Checker ....................................................... 249 13.3.4 Mesosimulator Network Checker ........................................................ 251 Draft 5 13.4 STATISTICAL METHODS FOR MODEL VALIDATION ................................................... 253 13.4.1 Statistical Model Validation in Aimsun objects ...................................... 257 13.5 DETECTION PATTERNS ............................................................................. 261 13.5.1 Overview .................................................................................... 261 13.5.2 Detection Pattern Creation without Detection Pattern Templates .............. 262 13.5.3 Detection Pattern Template ............................................................. 263 13.5.4 Detection Pattern Use .................................................................... 265 14 STATISTICAL SIMULATION RESULTS ............................................................ 266 14.1.1 14.1.2 14.1.3 14.1.4 14.1.5 14.1.6 14.1.7 14.1.8 14.1.9 15 Statistical Traffic Measures .............................................................. 266 Calculation of Traffic Statistics ......................................................... 272 Network Statistics ......................................................................... 272 Turning and Section Statistics ........................................................... 275 Subpath Statistics .......................................................................... 281 O/D Statistics ............................................................................... 283 Public Transport Statistics ............................................................... 288 Customisation of Statistical Output .................................................... 291 Detection Data Gathering ................................................................ 291 APPENDIX 1: DYNAMIC TRAFFIC ASSIGNMENT ................................................ 294 15.1 NEW IN AIMSUN 8.0 ............................................................................... 294 15.2 INTRODUCTORY REMARKS .................................................................... 294 15.3 FROM STATIC TO DYNAMIC TRAFFIC ASSIGNMENT ........................................ 295 15.4 ACHIEVING A DYNAMIC USER EQUILIBRIUM ................................................. 296 15.4.1 A heuristic approach in Aimsun ......................................................... 296 15.4.2 Algorithmic approaches for DUE ........................................................ 298 15.4.3 The convergence criterion ............................................................... 301 15.4.4 The computational framework in Aimsun ............................................. 302 15.5 HEURISTIC DYNAMIC TRAFFIC ASSIGNMENT: ESTIMATION OF PATH FLOW RATES BASED ON DISCRETE ROUTE CHOICE MODELS ..................................................................................... 304 15.5.1 Path Definition ............................................................................. 305 15.5.2 Path Selection .............................................................................. 323 15.6 DYNAMIC TRAFFIC ASSIGNMENT: ESTIMATION OF PATH FLOW RATES BASED ON DYNAMIC USER EQUILIBRIUM................................................................................................. 351 15.7 START AND CONTINUE A DYNAMIC USER EQUILIBRIUM.............................................. 353 16 APPENDIX 2: MICROSCOPIC SIMULATOR ....................................................... 355 16.1 NEW IN AIMSUN 8.0 ............................................................................... 355 16.2 MICRO SIMULATION PROCESS ...................................................................... 355 16.2.1 Function to determine whether the entrance to the network is possible ...... 357 16.2.2 Virtual Entrance Queues .................................................................. 360 16.2.3 Global modelling parameters - General ............................................... 361 16.2.4 Global modelling parameters - Two-Lane Car-Following ........................... 364 16.2.5 Global modelling parameters - Lane-changing ....................................... 365 16.2.6 Other Global Parameters ................................................................. 365 16.3 MODELLING VEHICLE MOVEMENT .................................................................. 366 16.3.1 Behavioural models ........................................................................ 368 16.4 TRAFFIC INCIDENTS ................................................................................ 391 16.5 SOLID LINES ....................................................................................... 391 16.6 CONNECTIONS AND CONFLICTS FINE TUNING ...................................................... 392 16.6.1 Connections ................................................................................. 392 16.6.2 Conflict ...................................................................................... 393 16.7 EXPERIMENT EDITING .............................................................................. 394 16.7.1 Behaviour Folder ........................................................................... 394 16.7.2 Reaction Time Folder ..................................................................... 395 16.8 PUBLIC TRANSPORT MODELLING ................................................................... 396 16.8.1 Public Transport Vehicle’s Modelling .................................................. 396 16.9 PREFERENCES ...................................................................................... 402 16.10 ENVIRONMENTAL MODELS .......................................................................... 404 16.10.1 Fuel Consumption Model ................................................................. 404 Draft 6 16.10.2 QUARTET Pollution Emission Model .................................................... 407 16.10.3 Panis et al Emission Model ............................................................... 410 16.11 TUNING VEHICLE MODELLING PARAMETERS IN AIMSUN ............................................. 416 16.11.1 Influence of Global Parameters ......................................................... 416 16.11.2 Influence of Section Parameters ........................................................ 417 16.11.3 Influence of Vehicle Parameters ........................................................ 417 16.11.4 On-ramp Calibration ...................................................................... 417 17 APPENDIX 3: MESOSCOPIC SIMULATOR ........................................................ 419 17.1 NEW IN AIMSUN 8 ................................................................................. 419 17.2 SIMULATION PROCESS .............................................................................. 419 17.2.1 Discrete-Event Simulation ................................................................ 419 17.3 NETWORK REPRESENTATION ....................................................................... 421 17.4 TRAFFIC MODELLING............................................................................... 423 17.4.1 Traffic Demand Data ...................................................................... 423 17.4.2 Vehicle Entrance Process ................................................................. 423 17.4.3 Modelling Vehicle Movement ............................................................ 424 17.4.4 Node Model ................................................................................. 426 17.5 SIMULATION EXAMPLE ............................................................................. 432 17.6 TRAFFIC INCIDENTS ................................................................................ 435 17.7 PUBLIC TRANSPORT MODELLING ................................................................... 436 17.8 DETECTOR EMULATION ............................................................................. 437 17.9 GLOBAL MODELLING PARAMETERS - GENERAL ...................................................... 437 17.9.1 Driver’s reaction time .................................................................... 437 17.9.2 Driver’s reaction time at traffic light ................................................. 438 17.10 EXPERIMENT EDITING .............................................................................. 438 17.10.1 Behaviour Folder ........................................................................... 438 17.10.2 Reaction Time Folder ..................................................................... 438 17.10.3 Random Seeds .............................................................................. 439 18 APPENDIX 4: HYBRID SIMULATOR ............................................................... 441 18.1 INTRODUCTION .................................................................................... 441 18.2 EXPERIMENT DEFINITION ........................................................................... 445 18.3 SIMULATION PROCESS .............................................................................. 450 MODEL VEHICLE MOVEMENT .............................................................................. 451 18.4 ........................................................................................................ 451 18.4.1 Meso to Micro ............................................................................... 451 18.4.2 Micro to Meso ............................................................................... 452 18.5 EXPERIMENT EDITING .............................................................................. 453 18.5.1 Behaviour Folder ........................................................................... 453 18.5.2 Reaction Time Folder ..................................................................... 454 19 APPENDIX 5: OUTPUT DATABASE DEFINITION ............................................... 456 19.1 META INFORMATION TABLES ....................................................................... 456 19.1.1 SIM_INFO Table ............................................................................. 456 19.1.2 META_INFO Table .......................................................................... 457 19.1.3 META_SUB_INFO ............................................................................ 457 19.1.4 META_COLS.................................................................................. 458 19.2 INFORMATION TABLES ............................................................................. 458 19.2.1 Example ...................................................................................... 459 19.3 MICROSCOPIC DATABASE ........................................................................... 461 19.4 MESOSCOPIC DATABASE............................................................................ 477 19.5 HYBRID DATABASE ................................................................................. 488 19.6 DYNAMIC TRAFFIC ASSIGNMENT .................................................................... 499 20 APPENDIX 6: APA FIXER ........................................................................... 500 20.1 20.2 20.3 20.4 Draft INTRODUCTION .................................................................................... 500 FUNCTIONALITY ................................................................................... 500 ALLOWED MODIFICATIONS .......................................................................... 500 ALLOWED SIMULATION TYPES ...................................................................... 501 7 20.5 20.6 USAGE ............................................................................................. 501 OUTPUT ........................................................................................... 501 21 APPENDIX 7: TRAFFIC ARRIVALS FORMAT FILE .............................................. 502 22 REFERENCES ......................................................................................... 505 Draft 8 Figure 1 Aimsun Environment ........................................................ 19 Figure 2 New Initial State Menu ..................................................... 22 Figure 3 Initial State Editor .......................................................... 22 Figure 4 Storing the Initial State .................................................... 23 Figure 5 Initial State Chooser ........................................................ 23 Figure 6 Entrances to a Section ...................................................... 26 Figure 7 New Traffic Arrivals Menu.................................................. 28 Figure 8 Traffic Arrivals Editor....................................................... 28 Figure 9 Traffic Arrivals profile ...................................................... 29 Figure 10 Storing the Traffic Arrivals of a dynamic simulation ................. 30 Figure 11 Traffic Arrivals selection in a traffic demand ......................... 30 Figure 12 Exponential Distribution .................................................. 31 Figure 13 Uniform Distribution ....................................................... 32 Figure 14 Normal distribution ........................................................ 33 Figure 15 Trip Generation Comparison ............................................. 34 Figure 16 Normal Distribution ........................................................ 38 Figure 17 ................................................................................ 39 Figure 18 Vehicle Attributes – Dynamic Models folder - Main folder ........... 41 Figure 19 Vehicle Type Editor – Dynamic Models Folder - Experiment Defaults Subfolder .......................................................................... 42 Figure 20 Vehicle Type Editor – Microscopic Model Folder - Main Subfolder .. 45 Figure 21 2D Shapes Folder ........................................................... 47 Figure 22 3D Shapes Folder ........................................................... 48 Figure 23 Fuel Consumption Folder ................................................. 49 Figure 24 QUARTET Emission Model Folder ........................................ 51 Figure 25 ................................................................................ 52 Figure 26 ................................................................................ 53 Figure 27 Section editor - Lanes folder ............................................. 56 Figure 28 Node editor - Main folder ................................................. 57 Figure 29 Node editor – Main Folder – Dynamic Models folder for a turn ...... 58 Figure 30 Example of network with different turning look-ahead distance ... 60 Figure 31 Visibility Distance of a Section Incident ................................ 61 Figure 32 Visibility Distance of a Reserved Lanes in a section .................. 62 Figure 33 Visibility Distance of a Lane Closure .................................... 62 Figure 34 Visibility Distance of a Turning Closure ................................ 63 Figure 35 Visibility Distance of a Public Transport Stop ......................... 63 Figure 36 Example of a simple intersection, with signal groups ................ 65 Figure 37 Example of rights of way sequence for the junction in .............. 66 Figure 38 Phase modelling for the junction in Figure 37 ......................... 66 Figure 39 Red percentage modelling of the yellow time ........................ 67 Figure 40 Ramp metering layout..................................................... 68 Figure 41 Green Time Metering Editor .............................................. 69 Figure 42 Control Information for a Green Time Metering....................... 69 Figure 43 Green Time by Lane Metering Editor ................................... 70 Figure 44 Control Information for a Green Time by Lane Metering ............ 71 Figure 45 Flow Metering Editor ...................................................... 71 Figure 46 Control information for a Flow Metering ............................... 72 Figure 47 Actual vs theoretic state change ........................................ 73 Figure 48 Setting Delay Metering .................................................... 73 Figure 49 Delay Metering Editor ..................................................... 74 Draft 9 Figure 50 Flow-ALINEA Metering Control Plan Editor ............................. 75 Figure 51 Flow-ALINEA Metering Properties Editor ............................... 75 Figure 52 Allowable Gaps ............................................................. 78 Figure 53 Single Ring Controller ..................................................... 81 Figure 54 Dual Ring Controller ....................................................... 81 Figure 55 Rings and barriers editing ................................................ 82 Figure 56 Actuated control interphase’s dynamic profile ....................... 84 Figure 57 Dialog window for the Basics Phase Definition ........................ 85 Figure 58 Actuated Control Parameters ............................................ 86 Figure 59 Actuated control’s detectors............................................. 88 Figure 60 Graphic phases ............................................................. 89 Figure 61 Bus Pre-emption folder ................................................... 92 Figure 62 Min Duration parameter in Fixed Control .............................. 92 Figure 63 Yield sign for right turn in a junction ................................... 93 Figure 64 Creating a pedestrian type from the Project menu .................. 95 Figure 65 The Pedestrian Types folder ............................................. 96 Figure 66 Pedestrian Type Settings window ....................................... 96 Figure 67 Speed Profile Histogram .................................................. 97 Figure 68 Available 2D shapes ....................................................... 98 Figure 69 Selecting 3D shapes and % of pedestrian type ......................... 98 Figure 70 Pedestrian Crossing Tool .................................................. 99 Figure 71 Pedestrian crossing (drag the point circled in red to change its length) ............................................................................. 99 Figure 72 Signal Group Editor ....................................................... 100 Figure 73 Pedestrian Area Tool ..................................................... 100 Figure 74 Polyline Obstacle Tool ................................................... 101 Figure 75 Polyline obstacle automatically adjusts to fit geometry ............ 101 Figure 76 Polygon Obstacle Tool.................................................... 101 Figure 77 Polygon obstacle automatically adjusts to fit geometry ............ 102 Figure 78 Layer context menu and Generate Pedestrian Obstacles option .. 102 Figure 79 Layer Obstacle Editor window .......................................... 103 Figure 80 Network with extruded polygons ....................................... 104 Figure 81 Layer Obstacle Editor window with settings .......................... 104 Figure 82 New obstacles are automatically generated .......................... 105 Figure 83 CAD Layer .................................................................. 105 Figure 84 Layer Obstacle Editor window with settings .......................... 106 Figure 85 CAD in red.................................................................. 106 Figure 86 Generate Pedestrian Obstacles option ................................ 107 Figure 87 Pedestrian area obstacles in green ..................................... 108 Figure 88 Generating obstacles for a single network object ................... 108 Figure 89 Node obstacle in brown .................................................. 109 Figure 90 How to create a pedestrian centroid configuration ................. 110 Figure 91 Entrance Centroid Tool .................................................. 110 Figure 92 Entrance centroid in green .............................................. 111 Figure 93 Exit Centroid Tool ........................................................ 111 Figure 94 Exit centroid in red ....................................................... 112 Figure 95 Decision Node Tool ....................................................... 113 Figure 96 Decision nodes in dark blue ............................................. 113 Figure 97 Focal point at centre of decision node ................................ 113 Figure 98 Focal segment in red ..................................................... 114 Draft 10 Figure 99 Service Point Tool ........................................................ 114 Figure 100 Service Point ............................................................. 115 Figure 101 Service Point Editor ..................................................... 115 Figure 102 Distribution points....................................................... 116 Figure 103 Level Change Object Tool .............................................. 117 Figure 104 Level Change Object Editor ............................................ 117 Figure 105 Creating a new pedestrian O/D route ................................ 118 Figure 106 Pedestrian O/D Route Editor .......................................... 118 Figure 107 Example of a pedestrian O/D route .................................. 119 Figure 108 Creating a new pedestrian O/D matrix ............................... 119 Figure 109 Pedestrian O/D Matrix Editor .......................................... 120 Figure 110 Pedestrian O/D route assignment ..................................... 120 Figure 111 Public Transport Stop Attributes ...................................... 121 Figure 112 Entrance / Exit Public Transport Stop Generation ................. 122 Figure 113 PT Stop with centroids.................................................. 122 Figure 114 PT Line Timetable Editor ............................................... 123 Figure 115 Maximum Capacity Attribute .......................................... 124 Figure 116 Vehicle attributes ....................................................... 125 Figure 117 Vehicle Doors editor .................................................... 125 Figure 118 Multiple doors simulation .............................................. 126 Figure 119 O/D Matrix Editor........................................................ 126 Figure 120 Scenario Editor, Aimsun API tab, for activating the Legion Extension ......................................................................... 127 Figure 121 Legion Extension Editor ................................................ 128 Figure 122 Active Service Points .................................................... 129 Figure 123 Using ORA file option ................................................... 129 Figure 124 Traffic demand showing a combined car O/D matrix and pedestrian O/D matrix ....................................................................... 130 Figure 125 Direction modifiers ...................................................... 131 Figure 126 Public Transport Stop Legion settings ................................ 132 Figure 127 Relation between Pedestrian Type ID and O/D matrix Pedestrian Type ............................................................................... 133 Figure 128 Dynamic Scenario Output definition .................................. 133 Figure 129 Crossing Influence Area ................................................. 135 Figure 130 Pedestrian Crossing Area ............................................... 135 Figure 131 Scenario creation possibilities ......................................... 142 Figure 132 Scenario Editor - Main Folder .......................................... 143 Figure 133 Scenario Editor - Output folder ....................................... 144 Figure 134 Scenario Editor - Output folder – Database Parameters editor ... 145 Figure 135 Scenario Editor - Output folder ....................................... 146 Figure 136 Scenario Editor - Output folder - Statistics subfolder .............. 147 Figure 137 Scenario Editor - Output folder - Statistics subfolder - Sections Statistics .......................................................................... 149 Figure 138 Scenario Editor - Output folder - Statistics subfolder - Nodes Statistics .......................................................................... 150 Figure 139 Scenario Editor - Output folder - Statistics subfolder – OD Matrices ..................................................................................... 151 Figure 140 Scenario Editor - Output folder - Statistics subfolder - PT Lines Statistics .......................................................................... 152 Figure 141 Scenario Editor - Output folder - Paths subfolder .................. 152 Draft 11 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Draft 142 Aimsun for Legion activation .......................................... 154 143 Trajectories subfolder .................................................. 155 144 Scenario Editor - Aimsun API Folder .................................. 156 145 Scenario Editor - Variables folder ..................................... 157 146 Scenario editor - Strategies & Conditions folder ................... 157 147 Scenario's context menu ................................................ 158 148 Experiment type definition ............................................ 158 149 Experiment editor - Main folder ....................................... 161 150 Experiment editor - Arrivals folder ................................... 163 151 Overriding the global arrivals model for an individual centroid .. 164 152 Experiment editor – Dynamic Traffic Assignment folder........... 166 153 Experiment editor - Variables folder ................................. 167 154 Experiment editor - Policies folder ................................... 167 155 Experiment's context menu ............................................ 168 156 Context Menu for creating a replication ............................. 168 157 Creating replications editor............................................ 168 158 Replication editor – Main folder ....................................... 170 159 Replication editor – Output folder .................................... 170 160 Batch Simulation dialog ................................................ 171 161 Animated Simulation task bar ......................................... 172 162 Replication Context Menu .............................................. 172 163 Aggregation Interval Definition ........................................ 173 164 Context Menu for creating averages .................................. 173 165 Average editor main folder ............................................ 174 166 Average Context Menu .................................................. 175 167 Animated Simulation Task bar ......................................... 176 168 Vehicles information in an Animated Simulation ................... 177 169 Aimsun Batch Replication .............................................. 179 170 Aimsun Batch Result .................................................... 180 171 Creation of a Strategy .................................................. 182 172 Strategy Editor ........................................................... 183 173 Creating a Policy from Strategy Context Menu...................... 183 174 Policy Editor .............................................................. 184 175 Trigger Editor ............................................................ 185 176 Creation of an Action ................................................... 187 177 Lane Closure Action Editor ............................................. 188 178 Turn Closure Action Editor ............................................. 189 179 Turn closure with visibility distance .................................. 190 180 Speed Change Action Editor ........................................... 190 181 Forced Turn Action Editor .............................................. 192 182 Destination Change Action Editor ..................................... 193 183 Section Incident Action Editor ......................................... 194 184 Periodic Section Incident Action Editor .............................. 195 185 Reserved Lane DeactivationAction Editor............................ 195 186 Control Plan Change Action Editor .................................... 196 187 Section Behavioral Parameters Change Editor ...................... 196 188 Problem Editor ........................................................... 197 189 VMS Messages definition in an action editor ......................... 198 190 Creation of an Incident ................................................. 199 191 Incident creation in the active 2D View .............................. 200 12 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Draft 192 Log Window messages when activating and deactivating actions 200 193 2D Simulation Animation - Vehicles in detail ........................ 201 194 Example of attributes added in a section ............................ 203 195 Example of time series added in a section .......................... 204 196 Vehicle Information dialog Window ................................... 205 197 Simulation Vehicle - Static Attributes folder ........................ 207 198 Simulation Vehicle - Dynamic Attributes folder .................... 207 199 Simulation Vehicle - Time Series folder .............................. 208 200 Simulation Vehicle - Path folder ...................................... 208 201 Simulation Control folder in the Node editor ....................... 209 202 Simulation Control folder for Actuated Control..................... 210 203 Simulation Control folder for Bus Pre-emption ..................... 211 204 Traffic Lights ............................................................. 212 205 Traffic Lights sharing a lane ........................................... 213 206 Turning movement with permanent right of way ................... 214 207 Space Time Diagram Dialog ............................................ 215 208 Detector Set editing .................................................... 216 209 Removing a detector .................................................... 216 210 Diagram Output Definition ............................................. 217 211 Space / Time diagram .................................................. 217 212 Space / Space Diagram ................................................. 218 213 Analyser Dynamic Label Menu ......................................... 219 214 Node Analyser Editor .................................................... 219 215 Analyser Dynamic Label ................................................ 220 216 Refresh Statistics for a Grouping ...................................... 221 217 FPZ Exporter activation ................................................ 221 218 FPZ Exporter options .................................................... 222 219 Setting up vehicle type length ........................................ 223 220 Resulting 3D scene in Civil View(R) with two vehicle types ....... 224 221 Time Series editor ....................................................... 224 222 Available actions in the Time Series editor.......................... 225 223 Time Series editor ....................................................... 225 224 Min Max Editor ........................................................... 226 225 Table view mode when visualizing a time series ................... 226 226 Time series comparison ................................................ 227 227 Output Comparison option menu ...................................... 227 228 Data Comparison Dialog ................................................ 228 229 Legend from a comparison using hypothesis testing ............... 230 230 Time View Tools ......................................................... 230 231 Regression Plot Dialog .................................................. 230 232 Decision Table ........................................................... 231 233 ODBC Data Source Administrator ...................................... 232 234 Create New Data Source dialog window ............................. 233 235 ODBC Microsoft Access .................................................. 234 236 External Scenarios ....................................................... 234 237 Generate Dynamic Traversal option .................................. 236 238 Dynamic Traversal Generation Parameters .......................... 236 239 Dynamic Traversal Generation Output ............................... 237 240 Experimental Nature of Simulation ................................... 238 241 Steps in a Simulation Study ............................................ 240 13 Figure 242 Detailed methodological steps of the model building and use process ............................................................................ 241 Figure 243 Timing and relationships of validation, verification and establishing credibility......................................................................... 243 Figure 244 Methodological framework for the validation of the simulation model by comparison with the observed system ........................... 245 Figure 245 Building a network model in Aimsun ................................. 246 Figure 246 Check and Fix Network Tool ........................................... 247 Figure 247 Checking the Network including centroids .......................... 248 Figure 248 Enabling the Microsimulator Network Checker...................... 249 Figure 249 Microsimulator Network Checker Editor ............................. 250 Figure 250 Detecting a Stationary Vehicle with the Microsimulator Network Checker ........................................................................... 251 Figure 251 Enabling the Mesosimulator Network Checker ...................... 252 Figure 252 Mesosimulator Dynamic Network Checker ........................... 252 Figure 253 Statistics for model validation – Graph view ........................ 258 Figure 254 Statistics for model validation – Regression view ................... 258 Figure 255 Statistics for model validation – Table view ......................... 259 Figure 256 Theil Validation global view ........................................... 260 Figure 257 GEH Validation global view ............................................ 261 Figure 258 Detection Pattern Editor ............................................... 262 Figure 259 Detection Pattern Template Editor ................................... 263 Figure 260 Adding a detection event to detection pattern and simulation using detection pattern template.................................................... 265 Figure 261 Subpath Editor ........................................................... 269 Figure 262 Subpath editor and sections in the active 2D view ................. 270 Figure 263: Demand moved as a function of iteration number using MSA and WMSA .............................................................................. 301 Figure 264 Conceptual diagram of the heuristic dynamic assignment ........ 303 Figure 265 Dynamic Traffic assignment Server structure ....................... 304 Figure 266 Example of Aimsun Network ........................................... 307 Figure 267 Representation of previous Network for Shortest Path Calculation ..................................................................................... 307 Figure 268 Cost Function for each turn ............................................ 309 Figure 269 Example of Aimsun network ........................................... 310 Figure 270 Left turning............................................................... 310 Figure 271 Right turning ............................................................. 310 Figure 272 Network of Figure 271 represented in terms of links and nodes. 310 Figure 273 Generic scheme of k-Shortest Path Algorithm ...................... 320 Figure 274 Calculation of shortest paths in a fixed using travel time in free flow Conditions model .......................................................... 326 Figure 275 Calculation of shortest paths in a fixed using travel time during warm-up period model ......................................................... 327 Figure 276 Calculation of shortest paths in a variable routes model ......... 328 Figure 277 Dynamic Traffic Assignment parameters definition window ...... 329 Figure 278 Use of Statistical data in the calculation of Shortest Paths ....... 330 Figure 279 Setting the same number of paths for all vehicles ................. 332 Figure 280 Setting different number of paths for different vehicle types ... 332 Figure 281 Binomial Model (k=3, p=0.9) ........................................... 333 Figure 282 Stochastic Route Choice parameters window. Binomial Model ... 334 Draft 14 Figure 283 Proportional function shape ........................................... 335 Figure 284 Stochastic Route Choice model window. Proportional Model ..... 336 Figure 285 Logit function shape .................................................... 338 Figure 286 Stochastic Route Choice parameters window - Logit Model....... 339 Figure 287 Overlapping Paths ....................................................... 340 Figure 288 Example of network with overlapped paths ......................... 341 Figure 289 Stochastic Route Choice parameters window - C-Logit Model .... 343 Figure 290 Stochastic Route Choice parameters window - User-Defined Model ..................................................................................... 344 Figure 291 Stochastic Route choice parameters window - Enroute Assignment Percentages ...................................................................... 349 Figure 292 Example of Origin/Destination Considers Percentages ............ 350 Figure 293 DUE Stop Criteria Parameters definition ............................. 352 Figure 294 DUE Parameters ......................................................... 353 Figure 295 The Microsimulation Process in Aimsun (Traffic States) ........... 356 Figure 296 The Aimsun Microsimulation Process (Route-Based) ............... 357 Figure 297 Variable Reaction Time - Probability Function...................... 362 Figure 298 Experiment editor - Reaction Time folder ........................... 363 Figure 299 Two-Lane Car-Following absolute ..................................... 371 Figure 300 Two-Lane Car-Following relative...................................... 373 Figure 301 Distance Zone Variability definition .................................. 376 Figure 302 Forward Gap Evaluation ................................................ 380 Figure 303 Adjacent Gap Evaluation ............................................... 380 Figure 304 Backward Gap Evaluation .............................................. 380 Figure 305 Comparison between new two lane car following and Gipps ..... 382 Figure 306 Gap-acceptance model ................................................. 386 Figure 307 Higher Priority vehicles considered at Give Way ................... 386 Figure 308: Overtaking desirability as a function of speed difference between the desired speed of the vehicle and its predecessor in the queue and the delay imposed by the queue. .................................................. 389 Figure 309: Overtaking desirability as a function of Rank in queue. .......... 389 Figure 310:Overtaking desirability as a function of remaining travel time. . 389 Figure 311 Connections tab in Advanced Node Editor ........................... 392 Figure 312 Junction Turnings ....................................................... 393 Figure 313 Turning entity conflicts ................................................. 393 Figure 314 Conflict Zone Boundaries ............................................... 393 Figure 315 Conflicts tab in Advanced Node editor ............................... 394 Figure 316 Micro Experiment editor - Behaviour folder ......................... 395 Figure 317 Micro Experiment editor - Reaction Time folder ................... 395 Figure 318 Micro Experiment editor - Reaction Time folder - Variable reaction time ............................................................................... 396 Figure 319 Public Transport Vehicle - Static Attributes ......................... 397 Figure 320 Public Transport Vehicle - Dynamic Attributes ..................... 398 Figure 321 Stopping at a Normal Bus Stop ........................................ 400 Figure 322 Stopping at a Bus Bay Stop ............................................. 401 Figure 323 Graphical Timetable showing one public transport line ........... 401 Figure 324 Aimsun Microsimulator Preferences .................................. 402 Figure 325 Fuel Consumption and Instant emission options in the Dynamic Scenario editor................................................................... 404 Figure 326 Fuel Consumption values defined in the Vehicle Type editor .... 406 Draft 15 Figure 327 QUARTET pollution emission values defined in the Vehicle Type editor .............................................................................. 409 Figure 328 Panis et Al pollution emission values defined in the Vehicle Type editor .............................................................................. 411 Figure 329 Node Server example ................................................... 421 Figure 330 Wrong section detailed speed by segment and/or lane definition. ..................................................................................... 422 Figure 331 Valid section detailed speed by segment and/or lane definition. 422 Figure 332 Mesoscopic network representation .................................. 422 Figure 333 Vehicle entrance process structure ................................... 424 Figure 334 Modelling Vehicle Movement illustration ............................ 425 Figure 335 Give way model situations ............................................. 427 Figure 336 Give way model diagram ............................................... 427 Figure 337 Mesoscopic maximum gap function ................................... 428 Figure 338 Give way model example ............................................... 429 Figure 339 Mesoscopic give way model calibration parameters ............... 429 Figure 340 Turnings connectors used to calculate entrance lanes. ........... 431 Figure 341 Look ahead model example ............................................ 431 Figure 342 Lane selection penalisation options. ................................. 432 Figure 343 Network for the simulation example ................................. 433 Figure 344 Traffic incident modelling in mesoscopic simulation .............. 435 Figure 345 Variable Reaction Time - Probability Function...................... 438 Figure 346 Meso Experiment editor - Behaviour folder ......................... 438 Figure 347 Meso Experiment editor - Reaction Time folder .................... 439 Figure 348 Meso Experiment editor - Reaction Time folder - Variable reaction time ............................................................................... 439 Figure 349 Result editor - Atributes folder ....................................... 440 Figure 350 Combining Meso and Micro approaches .............................. 442 Figure 351 Conceptual Architecture of the Integrated Platform .............. 442 Figure 352 An example of multilevel network parameters editing ............ 443 Figure 353 An example of multilevel network representation: node-link (left and right up), detailed geometry (right bottom) ........................... 444 Figure 354 Integration of the Dynamic Traffic Assignment Server and the Hybrid Network Loading ........................................................ 445 Figure 355 Hybrid tab in the experiment editor ................................. 446 Figure 356 Microsimulation area creation ......................................... 447 Figure 357 Microsimulation area Polygon and line in the Project Browser ... 447 Figure 358 Microsimulation area editor ........................................... 448 Figure 359 Editing sections in the microsimulation area editor ............... 448 Figure 360 Adding sections to the microsimulation area........................ 449 Figure 361. Hybrid simulation process ............................................. 450 Figure 362 Micro to Meso boundary model ........................................ 452 Figure 363 Fundamental diagram used to transfer from micro to meso ...... 452 Figure 364 Hybrid Experiment editor - Behaviour folder ....................... 454 Figure 365 Hybrid Experiment editor - Reaction Time folder .................. 454 Figure 366 Hybrid Experiment editor - Reaction Time folder - Variable reaction time..................................................................... 455 Figure 367 Example of a traffic arrival file format .............................. 502 Figure 368 Vehicle arrival definition ............................................... 503 Draft 16 1 Introduction Aimsun has three components that allow dynamic simulations, the Microscopic Simulator, the Mesoscopic simulator and the Hybrid Simulator. They can deal with different traffic networks: urban networks, freeways, highways, ring roads, arterials and any combination thereof. The dynamic simulators have been designed and implemented as a tool for traffic analysis to help traffic engineers in the design and assessment of traffic systems. They have proven to be very useful for testing new traffic control systems and management policies, based either on traditional technologies or as implementation of Intelligent Transport Systems. In this manual, any reference to Aimsun Dynamic simulators is referred without any distinction to the Microsimulator, Mesosimulator and Hybrid simulators. Aimsun Dynamic simulators can simulate adaptive traffic control systems such as SCATS, SCATS-RMS, VS-PLUS, UTOPIA, SCOOT and C-Regelaar; vehicle actuated, control systems that give priority to public transport, Advanced Traffic Management Systems (using VMS, traffic calming strategies, ramp metering policies, etc), Vehicle Guidance Systems, Public Transport Vehicle Scheduling and Control Systems or applications aimed at estimating the environmental impact of pollutant emissions, and energy consumption. The Microsimulator follows a microscopic simulation approach. This means that the behaviour of each vehicle in the network is continuously modelled throughout the simulation time period while it travels through the traffic network, according to several vehicle behaviour models (e.g., car following, lane changing). The Microscopic simulator in Aimsun is a combined discrete/continuous simulator. This means that there are some elements of the system (vehicles, detectors) whose states change continuously over simulated time, which is split into short fixed time intervals called simulation cycles or steps. There are other elements (traffic signals, entrance points) whose states change discretely at specific points in simulation time. The system provides highly detailed modelling of the traffic network, it distinguishes between different types of vehicles and drivers, it enables a wide range of network geometries to be dealt with, and it can also model incidents, conflicting manoeuvres, etc. Most traffic equipment present in a real traffic network is also modelled in the Microsimulator: traffic lights, traffic detectors, Variable Message Signs, ramp metering devices, etc. The microsimulator in Aimsun can simulate vehicles and pedestrians at the same time. The pedestrians are simulated by using an embedded Legion pedestrian simulator engine. Refer to the Legion for Aimsun section for more details about pedestrians in Aimsun. Draft 17 In the Mesoscopic approach, the vehicle is also modelled as an individual entity, exactly the same as the Microscopic approach but the behavioural models (e.g., car following, lane changing, etc) are simplified with a slight loss of realism in order to have a simulation event oriented. In the Hybrid approach, the simulation concurrently applies the microscopic model in certain selected areas and the mesoscopic in the rest. The hybrid model is recommended for large-scale networks with specific areas where the level of detail needs to be microscopic (for example, for actuated control, public transport Pre-emption, pedestrian modelling, detection or adaptive control systems) but with a global network evaluation. The use of the mesoscopic model in the other areas means that the simulation is more reliable and requires less computational time. The input data required by Aimsun Dynamic simulators is a simulation scenario, and a set of simulation parameters that define the experiment. The scenario is composed of four types of data: network description, traffic control plans, traffic demand data and public transport plans. The simulation parameters are fixed values that describe the experiment (simulation time, warm-up period, statistics intervals, etc) and some variable parameters used to calibrate the models (reaction times, lane changing zones, etc). The outputs provided by Aimsun Dynamic simulators are a continuous animated graphical representation of the traffic network performance, both in 2D and 3D, statistical output data (flow, speed, journey times, delays, stops), and data gathered by the simulated detectors (counts, occupancy, speed). Furthermore, for the Aimsun microscopic simulator and the microscopic areas in the Aimsun hybrid simulator a continuous animation of the simulation vehicles is also produced. 1.1 Microsimulator, Aimsun Mesosimulator, Hybrid simulator and This manual mainly covers the three dynamic simulators in Aimsun: the Microscopic traffic simulator, the Mesoscopic traffic simulator and the Hybrid traffic simulator, which are integrated in the Aimsun transportation platform by TSS. The environment will always be called Aimsun, and the simulators called Microsimulator or Micro, Mesosimulator or Meso and Hybrid (when no confusion with other simulators is possible). Look into the Aimsun Users’ Manual for information about the environment and other integrated tools. Draft 18 Figure 1 shows the integration of Microscopic Simulator and Mesoscopic Simulator within Aimsun. GUI Editing 2D and 3D Animation DATA IMPORTERS - Traffic Data - Digital Maps GIS/CAD/Ortophotos ALMO Aimsun Macroscopic modelling Tools Microscopic Simulator EXTENSIBLE OBJECT MODEL MODEL IMPORTERS - GIS - CONTRAM - PARAMICS - CUBE Mesoscopic Simulator Hybrid Simulator TRAFFIC CONTROL Actuated, Adaptive MODEL DATABASE INTERFACES - EMME - SATURN SCENARIO ANALYSIS VALIDATION TOOL IMPORTERS & INTERFACES KERNEL TRAFFIC TOOLS Figure 1 Aimsun Environment 1.2 Input Data Requirements Dynamic simulation is characterised by the high level of detail at which the system is modelled. The quality of the model is highly dependent on the availability and accuracy of the input data. Therefore, the user must be aware that in order to build a good Aimsun model, the following data is required: 1.2.1 Network Layout An Aimsun traffic network model is composed of a set of sections (one-way links) connected to each other through nodes (intersections), which may contain different traffic features. To build the network model, the following input data is required:  Map of the area, preferably a digitized map in .DXF format.  Details of the number of lanes for every section, reserved lanes and side lanes (on and off ramps). Draft 19     Possible turning movements for every junction, including details about the lanes from which each turning is allowed and solid lines marked on the road surface. Speed limits for every section and turning speed for allowed turns at every intersection. Detectors: position and measuring capabilities. Variable Message Signs: position and (optionally) the possible messages. 1.2.2 Traffic Demand Data Traffic demand data can be defined in two different ways:  by the traffic flows at the sections  by an O/D matrix Depending on the type of model selected, the following input data must be provided: 1. Traffic Flows 1 o Vehicle types and their attributes o Vehicle classes (for reserved lanes) o Flows at the input sections (entrances to the network) for each vehicle type o Turning proportions at all sections for each vehicle type 2. O/D matrix o Centroid definitions: traffic sources and sinks o Vehicle Types and attributes o Vehicle Classes (for reserved lanes) o Number of trips going from every origin centroid to any destination one F 1.2.3 Traffic Control Aimsun takes into account different types of traffic control: traffic signals, give-way signs and ramp metering. The first and second types are used for junction nodes, while the third type is for sections that end at join nodes. The input data required to define the traffic control is as follows:  Signalized junctions: location of signals, the signal groups into which turning movements are grouped, the sequence of phases and, for each one the signal groups that have right of way, the offset for the junction and duration of each phase.  Unsignalized junctions: definition of priority rules and location of Yield and/or Stop Signs.  Ramp metering: location, type of metering, control parameters (green time, flow, flow-alinea or delay time). 1 Draft This is only available in Aimsun Micro. 20 1.2.4 Public Transport The user may opt to have Aimsun take Public Transport into account. The input data required to define Public Transport is as follows:  Public Transport Lines: a set of consecutive sections composing the route of a particular bus.  Reserved lanes.  Public Transport Stops: location, length and type of public transport stops in the network.  Allocation of Public Transport Stops to Public Transport Lines.  Timetable: departures schedule (fixed times or frequency), type of vehicle, and stop times (specifying mean and deviation) for each public transport stop. 1.2.5 Initial State2 The user may opt to start a simulation having vehicles distributed for the whole network. There are two possibilities to do it, the first one is applying a warm-up and the second one is using an Initial State. An Initial State is an object that keeps vehicle positions in a certain simulation time. It keeps track of private vehicles in sections and nodes and of Public Transport vehicles. Note that it will contain private vehicles only if they are simulated using an O/D based traffic demand. Also, initial state information is not stored in the ang file but in an external *.ais file that will be required to retrieve the information. The initial state can store the information of the vehicles at the end of the simulation or at any point during the simulation. Empty Initial States can be created to be later on filled with simulation data. To do so, select Demand Data/ New/ Initial State (see Figure 2). 2 Draft This is only available in Aimsun Micro. 21 Figure 2 New Initial State Menu Double clicking on the new object, the following dialog brings up. Figure 3 Initial State Editor Select the File location where Initial State information will be stored. To create an Initial State with the information at the end of a microscopic simulation, create an empty Initial State object first. Then, open the replication editor and tick to Store Vehicles at the End of the Simulation as Initial State. A list of all the available initial states will be displayed to select the one where the date will be written into. Run the simulation and the associated *.ais file will be filled with the vehicles data. To create an initial state with the information at an intermediate time during the microsimulation, run a microscopic replication and stop it at a certain simulation time. Then, right click on the current Draft 22 replication and select the Save Simulation State option (see Figure 4). Figure 4 Storing the Initial State If there are not any Initial States created a dialog to choose the file location where to store the initial state information (*.ais file) will appear. After selecting the file location a new Initial State object will be created inside the Demand Data folder. If there is any Initial State already created, the following dialog brings up to choose which Initial State will be stored (see Figure 5). Either an existing one or a new one can be chosen. Figure 5 Initial State Chooser Then, press the Ok button to store the contents into the file. 1.3 Note on Units Within this document, units for lengths, speeds, accelerations, etc. are expressed in metric form. Where the user has specified network units as being English (sometimes called Imperial), inputs to and outputs from the simulator will be in this form, unless explicitly stated otherwise (for example, environmental model parameters are only expressed in metric units). Internally, calculations are always made in metric units, though this will remain opaque to the user. Metric Imperial kilometres miles metres feet Draft 23 m/s m/s2 km/h Draft ft/s ft/s2 mph 24 2 Traffic Modelling 2.1 Traffic Demand Data Depending on the available traffic demand data, two different types of simulation are considered in Aimsun. One is based on input traffic flows and turning percentages, the other is based on O/D matrices and routes or paths. A collection of either traffic states or O/D matrices are grouped into a Traffic Demand object. For more information about defining a Traffic Demand, refer to the Aimsun Users’ Manual. 2.1.1 Vehicle Classification Regardless of the type of simulation, vehicles can be grouped at two different levels: vehicle classes and vehicle types. Vehicle Classes are only used for the reserved lane definition. For instance, these can include Public, Private, Emergency and HOV (high occupancy vehicle) classes, in order to be able to define reserved lanes in the network model for Public and Emergency classes as well as lanes for the HOV class. The use of Classes is optional, it is only required when there are reserved lanes in the network model. Vehicle Types refers to the different kinds of vehicles for which the traffic demand data is defined. Therefore, input flows and turning proportions, as well as number of trips in the O/D matrices, are distinguished for each vehicle type. For instance, vehicle types may be car, taxi, private-bus, public-bus, HGV (heavy goods vehicle), truck, ambulance, police-car, HOV-car. The use of Types in a model is always required, otherwise it is not possible to define traffic demand data. Physical characteristics or vehicle attributes such as width, length, speed, acceleration, deceleration, etc, may be defined for every Vehicle Type. A Class can be composed of one or more Types, and a Type may belong to none, one or several Classes. For example: Vehicle Class consists of Public Private Emergency HOV VehicleTypes public-bus, taxi, ambulance, police-car car, private-bus, HGV, truck, HOV-car ambulance, police-car HOV-car A reserved lane may be defined for a certain class. For instance, a reserved lane may be defined for Public transport. This lane would only be available for public-buses, taxis, ambulances and policecars. Draft 25 Refer to the Aimsun Users’ Manual for information about defining vehicle types, vehicle classes and reserved lanes. 2.1.2 Input Flows and Turning Proportions The traffic demand data can be composed of the input flows at the input sections of the network, and the turning proportions at every node of the network. Both can be defined by vehicle type. These data can be obtained as a result of a previous assignment model, from data collected by detectors or defined by the user as an experimental hypothesis. Vehicles are generated and input into the network through the input sections, following a random generation model based on the mean input flows for those sections. They are then distributed randomly throughout the network in accordance with the turning proportions defined at each section of the network. This means that vehicles do not “know” their complete path along the network, but only about their next turning movement. Aimsun can distinguish between the different entrances to a section, so different turning proportions can be defined. Each turning proportion will affect only the vehicles entering the section from each different entrance. Figure 6 gives an example of this. Section 3 has two possible entrances: sections 1 and 2. Therefore, the turning proportions for section 3 to sections 4 and 5 may be different for vehicles coming from section 1 to those coming from section 2. The same happens with section 5, whose entrances are sections 3 and 6. 4 1 3 2 5 6 Figure 6 Entrances to a Section Intervals between arrivals are determined from the mean flows of the input sections, applying any of the random distributions explained in section Traffic Generation. Vehicle type is assigned as a function of the proportions defined for each section. The input lane depends on the state of all lanes composing the section, the existence of reserved lanes and the vehicle type. Rightmost lanes (or leftmost lanes, depending on the Rule of the Road) are more likely to be used than central lanes. Draft 26 Input flows and turning proportions for a time slice and for a vehicle type compose a Traffic State. Refer to the Aimsun Users’ Manual for information about defining traffic states. 2.1.3 O/D matrices The traffic conditions to be simulated can be also defined by a set of O/D matrices, each one giving the number of trips from every origin centroid to every destination centroid, for a time slice and for a vehicle type. Vehicles are generated at each origin centroid and input into the network via the objects (sections or nodes) connected as ‘TO’ this source centroid. Then, vehicles are distributed along the network following shortest paths between origin and destination centroids. Finally, vehicles exit the network via the objects connected as ‘FROM’ the destination or sink centroid. When a vehicle is generated, the assignment of the vehicle to the objects connected to the centroid (i.e. sections and nodes) can be made based on probability, or made to depend on the path to destination. Using the probability-based approach, the user specifies a proportion of vehicles taking each of the possible objects connected to the centroid. On the other hand, using the destination-dependant approach, the system decides to which object each vehicle must be assigned, taking into account the best path to the actual destination of the vehicle. Refer to the Aimsun Users’ Manual for information about defining O/D matrices. 2.1.4 Traffic Arrivals Besides the O/D matrices the user may define as an input to the traffic demand a traffic arrival. The traffic arrival object is actually a XML file with a definition of vehicle arrivals, where a vehicle arrival is defined with the following information:  Vehicle type. This is the vehicle type identificator.  Generation time. This is the relative generation time from 0 to the duration of the simulation.  Generation seed. This is the seed that is going to be used to generate vehicles's phisical properties: vehicle length, vehicle desired speed, ...  Route choice seed. This is the seed that is going to be used to select the path this vehicle is going to follow.  Origin centroid and destination centroids.  Origin section and destination connector define the entrance and exit sections, for example if the origin and destination centroids are using percentages. Draft 27 These arrivals are generated together with the O/D matrices definition. So if there are 100 trips for a certain O/D pair in the O/D matrix and 50 trips defined in the traffic arrival the total number of vehicles generated for the O/D pair will be 150. The traffic arrivals file format is explained in appendix 21. An empty Traffic Arrivals object can be created to be later on filled with a simulation data. To do so, select Demand Data/ New/ Traffic Arrivals (see Figure 7). Figure 7 New Traffic Arrivals Menu Double clicking on the new object, the following dialog brings up. Figure 8 Traffic Arrivals Editor Select the File location where traffic arrivals information will be stored. Draft 28 Click on the Auto Retrieve option if you want to have the traffic arrivals information read when the Aimsun model is loaded. Define a Profiling Interval to display the number of vehicles in the Traffic Arrivals aggregated by the defined interval in the Profile tab of the traffic arrivals object. Figure 9 Traffic Arrivals profile To create a traffic arrivals file with the information at the end of a dynamic simulation, create an empty Traffic Arrivals object first. Then, open the dynamic scenario editor and in the Output folder, General subfolder tick to Store the Traffic Arrivals. In the Where part, select the desired Traffic Arrival object to store the simulation information into (as in Figure 10). Draft 29 Figure 10 Storing the Traffic Arrivals of a dynamic simulation To load a traffic arrivals object in a traffic demand open the traffic demand editor and select the desired traffic arrivals. Figure 11 Traffic Arrivals selection in a traffic demand Draft 30 2.2 Traffic Generation The time interval between two consecutive vehicle arrivals – the headway– is sampled from a random distribution – a headway model. When loading a traffic demand into Aimsun, that is either a set of traffic states or a set of O/D matrices, the user may select among different headway models: exponential, uniform, normal, constant, “ASAP” and external. ‘Exponential’ is the default distribution. Generation model is set globally on a per scenario basis; however, it may be overridden for individual centroids in the case of O/D traffic demand, or for individual sections in the case where demand is a traffic state. Vehicles generated from a traffic arrival use the generation time defined in the traffic arrival to enter into the network. 2.2.1 Exponential Time intervals between two consecutive vehicle arrivals (headway) at input sections are sampled from an exponential distribution (Cowan 1975). The mean input flow (in vehicles/second) is , and the mean time headway is calculated as 1/ seconds. Figure 12 Exponential Distribution The algorithm for calculating the time headway (t) is the following: u = random (0,1) if ( > 0.0) t = ((-1/)*ln(u)) else t = max_float endif 2.2.2 Uniform Time intervals between two consecutive vehicle arrivals (headway) at input sections are sampled from a uniform distribution. The mean headway (T) is taken as 1/ seconds,  being the mean input Draft 31 flow (in vehicles/second), and the range used for the distribution is [T-T/2, T+T/2]. Figure 13 Uniform Distribution The algorithm for calculating the time headway (t) is the following: if ( > 0.0) T = 1/ u = random (0,1) minU = -T/2 maxU = T/2 t = T+[minU+(maxU-minU)*u] else t = max_float endif 2.2.3 Normal Time intervals between two consecutive vehicle arrivals (headway) at input sections are sampled from a truncated normal distribution. The mean headway (T) is taken as 1/ seconds, where  is the mean input flow (in vehicles/second), and the variance () is taken as 10% of the mean. The range of the truncated normal is [T-2*, T+2*]. Draft 32 Figure 14 Normal distribution The algorithm for calculating the time headway (t) is the following: if ( > 0.0) T = 1/ n = t_normal (1,0.1) t = maximum [, n*T] else t = max_float endif (truncated normal) (  0,  > 0) 2.2.4 Constant Time intervals between two consecutive vehicle arrivals (headway) at input sections are always constant. The headway (t) is taken as 1/ seconds,  being the mean input flow (in vehicles/second). The algorithm for calculating the time headway (t) is the following: if ( > 0.0) t = 1/ else t = max_float endif 2.2.5 “ASAP” In this generation model, vehicles are entered in the network ‘as soon as possible’, i.e. as soon as there is some space available in the input section. This model is intended to make the most use of the network entrance capacity. It could be used, for example, for simulating evacuation situations. In this case, no headway is generated. At the beginning of each time slice, the total flow to be input during the slice is ‘piled up’ at the entrance section and vehicles are entered into the section one after the other as soon as the previous one has left enough space. Draft 33 2.2.6 External This option means that the user will introduce the vehicles into the network via the Aimsun Microsimulator API 3 . No vehicles are generated or input into the network via any section by the simulator itself. Therefore, an external DLL, user-defined program, is required to feed the network with vehicles. F F 2.2.7 Summary of Generation Figure 15 shows a comparison of traffic generation models. Results are for a demand of 60 vehicles over one hour onto a link in free flow. Figure 15 Trip Generation Comparison 2.2.8 Dealing with a fractional number of trips When the demand for a particular O/D pair during a certain time slice is less than 1, it is possible that no vehicle is scheduled for that particular slice. This apparently slight error may become very significant when the simulation period is composed by many time slices, or when there are many O/D pairs containing these small amounts. This can cause a situation in which a representative number of trips are not being generated. This problem can be attributed to the nature of the vehicle generation process in Aimsun. To calculate a vehicle arrival time, the time intervals between two consecutive vehicle arrivals (headway) are sampled from any of the available random distributions. When the flow is small, this time headway can be bigger than the time slice itself, which leads to no arrival during that slice, but during the next slice instead. However, when the 3 Draft This is only available in Aimsun Micro 34 simulation reaches the new slice, new arrivals according to the new input demand are scheduled and the pending arrivals are removed. For example, let us assume that =0.2 vehicles/minute is the mean input demand for a particular OD pair. The mean time headway is calculated as 1/ = 5 minutes. If we have a time slice of 1 minute, this means that during this time slice no vehicles would arrive, as the scheduled time for the next arrival goes beyond the end of the time slice. To solve this problem, there are two processes to consider: 1. The number of trips in the matrix doesn’t define the number of vehicles that will be generated, but the average headway between two vehicles. 2. The generation process is recalculated for every time slice and is carried out for every vehicle type. In each slice, Aimsun calculates the generation times for a specific vehicle type according to the following algorithm: NextTimeGeneration = = Initial Time of i-th Slice while (NextTimeGeneration
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