Research interests
Road and Pedestrian traffic
  • There are some strong similarities between road traffic and fluid flows. As a consequence, the modeling methods are quite similar, making it quite natural for a physicist to get some interest in the subject. Until now, I concentrated mainly on highway traffic, on the point of vue of modeling (cellular automata) or of data analysis (single car data obtained with magnetic loops)
    On this subject, I am collaborating mainly with Ludger Santen (Lab. of Theoretical Physics, Univ. des Saarlandes) and with the Laboratoire des Ponts et Chaussées (Paris).
  • In collaboration with Ludger Santen, we have studied how the introduction of a reaction time in a simple transport model could introduce some metastability in the system. There are strong evidences that metastability also occurs in real traffic, and our model suggests one basic mechanism to explain this phenomenon.
  • Analysis of single vehicle magnetic loop data :
    • I have proposed a simple scenario of rear end collisions in platoons, and used it as a criterium to evaluate the dangerosity of one-lane structures. The impact of several security measures could also be discussed.
    • The great amount of data I had allowed me to measure with high precision some velocity and time headway correlations, either on the same lane, or on adjacent lanes.
    • I have made the proposal that the response of a highway system to a local perturbation (on-ramp) could be used to test the validity of microscopic lane changing rules. Data analysis allowed to extract some basic properties of the relaxation length of the lane fractions after an on-ramp. The methodology was illustrated on a cellular automata model, but could be generalized to any simulator, including the commercial ones.
  • I am part of the PEDIGREE project on pedestrian traffic. We have realized several experiments in various settings, including bidirectional traffic in ring corridor, one-dimensional motion on a circle, binary or multiple interactions of pedestrians, oscillations at a bottleneck, etc.