Distributed Behavioral Simulation: an Innovative Way to Carry out Traffic Studies
A Champion, CS-SRILOG; J-M Auberlet, S Espi?, INRETS, FR
Simulation modeling is an increasingly popular and effective tool for analyzing a wide variety of dynamical problems. Road traffic is an example of such problems. Different types of traffic simulation models exist. Macroscopic models represent entities and their activities in some aggregate manner by values of density and speed. Microscopic models describe entities as individuals and mainly uses ?mathematical? car-following. These traffic simulation models are based upon the identification of experimental traffic laws which come from observations of the real traffic. In addition to these models, the French National Institute for Research in Transportation and Safety (INRETS) has done researches on road traffic simulation based on the driver behavior for more than ten years. The INRETS? ARCHISIM simulation tool makes use of a behavioral sub-model for driver decisions, which results from in-depth studies carried out in driving psychology for actual situations. In ARCHISIM, the individual actions and interactions of the various actors of the road situation produce traffic phenomena.
ARCHISIM is a behavioral simulation model and its implementation follows the multi-agent principles described in Distributed Artificial Intelligence. Within ARCHISIM, agents are simulated drivers in virtual vehicles. Each autonomous agent has a model of its environment and interacts with the other agents, the elements of the infrastructure and the road. Agents have goals, skills and their own attitude. Hence, the simulated road users can potentially react to any changing situations and the ?traffic system? can then show a greater aptitude to organize itself. Therefore, ARCHISIM is an innovative way to carry out traffic study because the hypotheses made are to model the drivers? behaviors instead of modeling the traffic flow phenomena.
ARCHISIM is a flexible tool for which a set of applications have been found: new road design and ITS test scenarios among others, in fact, any study relating to a modification of the ?traffic system?. ARCHISIM ?like mathematical models? can be used for various traffic studies. Although the model is fully distributed, thanks to always increasing computer power, ARCHISIM shows a high potential for the realization of a wide range of traffic studies. To more specifically develop ARCHISIM in the way to carry out high density traffic highway studies, a partnership between INRETS and CS-SRILOG (a company specialized in ITS and traffic management) has been set and significant works have been done. Indeed, test traffic studies involving infrastructure and adaptive ramp metering system evaluations were carried out in 2001. Recently, a first ?real? study was carried out in 2002 for a French highway management company to understand the reasons of some recurring congestion in order to find a solution.
In this paper, after the presentation of distributed behavioral road traffic simulation and the INRETS? simulation model ARCHISIM, we present a traffic study that SRILOG and INRETS are currently carrying out with ARCHISIM for a major French highway management company. This traffic study is the simulation of a 15km long 3-lane highway section in the Paris outskirts during the morning and the evening rush hours. The first step of this study aims at analyzing the actual traffic on the current network to highlights the drivers? behaviors in such conditions. The second step aims at testing this network in its current shape and in its 2005 and 2008 configurations with expected traffic.
Association for European Transport