Abstract

The large investments generally required by transportation projects have to be justified in a robust way. Therefore feasibility studies need to be carried out that validate the proposals, assess their expected impacts and provide the basis for sound cost benefit analysis. This is especially so when studying the possible deployment of Intelligent Traffic Systems (ITS) to discover the benefits that should be expected from their operation.

Microscopic traffic simulators are simulation tools that realistically emulate the flow of individual vehicles around a road network. They are proven tools for aiding transportation feasibility studies. This is not only due to their ability to capture the full dynamics of time dependent traffic phenomena, but also because they are capable of using behavioral models that can account for drivers’ reactions when exposed to ITS. GETRAM, presented in this poster, is a simulation environment with a microscopic traffic simulator (AIMSUN) at its heart. It provides:

• The ability to accurately represent any road network geometry: An easy to use Graphic User Interface (TEDI) that can use existing digital maps of the road network allows the user to model any type of traffic facility.
• Detailed modeling of the behavior of individual vehicles. This is achieved by employing sophisticated car-following and lane changing models that take into account both global and local phenomena that can influence each vehicle’s behavior. The high quality of these models has been proven in numerous field tests.
• An explicit reproduction of traffic control plans: pre-timed as well as those defined by TRANSYT, SYNCHRO or Nema’s standards. Auxiliary interfacing tools that allow the simulator to work with almost any type of real-time or adaptive signal control systems are also provided.
• Animated 2D and 3D output of the simulation runs. This is not only a highly desirable feature but can also aid the analysis and understanding of the operation of the system being studied and can be a powerful way to gain widespread acceptance of complex strategies.

Vehicles are assigned to routes according to a route choice model. Additionally AIMSUN allows vehicles to change their chosen route from origin to destination according to variations in traffic conditions as they travel through the road network. This provides the basis for heuristic traffic assignment.

AIMSUN doesn’t set any limits to the size of models that can be built and simulated. Efficient software development makes microsimulation with AIMSUN both practical and affordable, even on today’s laptop computers.

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