Techniques for rapid initialization in in-vehicle traffic simulators

On-line in-vehicle traffic simulation has been proposed as a means to provide predictions of future states of a traffic network based on current traffic conditions. The area covered by an in-vehicle simulation may change dynamically during the vehicle´s journey. This paper is concerned with the issue of initializing the state of new regions that are added to a running microscopic traffic simulation. A warm-up period is required where the new road segments must be populated with simulated vehicles. Techniques that convert vehicle flow rate and queue length information to vehicle positions and speeds are proposed to minimize this warm-up period. These techniques are evaluated and compared with respect to estimated travel times of vehicles traveling through different paths in the road network under different traffic conditions. Travel time predictions are compared to a microscopic simulation of the entire region.