1. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Transport Modelling Microsimulation Software

2. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Traffic Models Traffic Flow Models Level of Details MicroMesoMacro Operationalisation AnalyticalSimulation

3. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie The analytical models are, where the solution to a set of differential equations describing the traffic system is obtained analytically (using calculus) –Analytical models can be static and dynamic –Numerical methods are used for solutions The simulation models are, where the successive changes of the traffic system over time (space-time dynamics) are reproduced (approximated) in the model. –Simulation models are dynamic –Macroscopic, mesoscopic and microscopic

4. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Traffic Simulation Simulation: dynamic representation of real world by a computer model Traffic Simulation: application of computer models/simulations for scientific research in planning, training and demonstration purposes MAIN FACTORS INFLUENCING RESEARCH IN SIMULATION 1.Advance research in traffic theory 2.Advancement in computer hardware technology 3.Advancement in computer software technology 4.Development in information infrastructure 5.Increased importance of traffic and transportation in the society

5. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Aspects of road traffic simulation (1) 1.Transport networks cover wide physical areas 2.Large number of active participants or users and interaction among them 3.Objectives of the participants can be individual or social (system optimum vs. user optimum) 4.Presence of independent variables outside the control of the operator and the participants (the weather conditions, the number of users, etc.) 5.The variables can be stochastic (inherent randomness) and time varying in nature 6.Man-machine system, laws of interaction dependent on human perception

6. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Limitations of traffic simulations Simulations are resource limited –Resolution: Level of detail –Fidelity: Degree of realism –System size: The network size to be covered –Simulation speed: Speed of simulation compared to real time –Resources: Computational resources, programming time

7. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Analysis of Existing Models Dynamic behaviour of individual agents is explicitly simulated over both time and Space to generate aggregate system behaviour ‘Micro’ refers to the resolution at individual Vehicle level – inevitable requirement of detailed analysis 58 identified models of micro-simulation Models are mostly developed in North America, Europe, Australia and Japan Types of organisation involved: Research institutes, universities and industrial organisation

8. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Popular microsimulation models Existing Micro simulation Models

9. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Existing Micro simulation Models

10. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Micro-simulation models are essentially research products 9 of the popular models are commercial products (AIMSUN2, FLEXSYT II, FRESIM, HUTSIM, INTEGRATION, PARAMICS, THOREAU, TRAF-NETSIM and VISSIM) and are continuously in development Existing Micro simulation Models

11. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Objectives From model designer point, Quantify the benefits of Intelligent Transportation Systems (ITS), primarily Advanced Traveller Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS) Evaluation prior and in parallel with on street operation study of dynamic traffic control incident management schemes real-time route guidance strategies adaptive intersection signal controls ramp and mainline metering toll plazas and lane control systems (lane use signs, electronic toll collection, high occupancy vehicle lane, etc.) assessing the impact and sensitivity of alternative design parameters Existing Micro simulation Models

12. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Classification based on traffic conditions Existing Micro simulation Models

13. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Scale of applications Existing Micro simulation Models The scale of application varies then from small type, about 20 km, 50 nodes and 1000 vehicles, to large type, 200 nodes and many thousands vehicles PARAMICS can even simulate 1 million vehicles with 3000 nodes Highly specific objectives (models of the type "other" traffic condition) have a very small scale of application

14. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Objects modelled Existing Micro simulation Models

15. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Modelling Techniques Existing Micro simulation Models Weather conditions are modelled by the speed-acceleration behaviour (changes in the driver behaviour parameters) or by the free flow speed of vehicles. Parked vehicles are modelled by a particular destination node, side parking on links, temporary incidents or by a particular state of vehicle. Commercial vehicles are modelled by parameters such as power, mass, length, privilege on certain lanes. Pedestrians are taken into account when turning flows interact with pedestrian areas or in extending intersection all red periods to simulate walk periods.

16. TRANSPORT MODELLING Lecture 4 TRANSPORT MODELLING Lecture 4 26-Sep-08 bghosh@tcd.ie Modelling Techniques Existing Micro simulation Models Incidents are modelled by lane closure signs, blocked lanes, "scheduled vehicles" and slow vehicles. Public transport, essentially buses, are modelled by vehicles with fixed routes. Traffic calming measures are modelled by local speed limits, yield sign objects, Variable Message Signs and route guidance. Queue spill back is modelled by space constraint in car-following and in link changing. Weaving is modelled by forced lane changing, special lane changing behaviour, decision rules or lane changing logic. Roundabouts are modelled by lane segments and yield sign objects.