
Research interests
Road 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 or of data analysis (single car data obtained
with magnetic loops)

Modeling
 In collaboration with Ludger Santen (Lab. of Theoretical
Physics, Univ. des Saarlandes), 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.

In collaboration with H. Hilhorst and G. Schehr,
we have proposed a kinetic model for a
bidirectional road, with an explicit modeling
of passing requirements, and shown that a
spontaneous asymmetry could arise between
the lanes, in a parameter range that should
allow to observe it on national roads.

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 onelane structures observed in real data.
The impact of several security measures could also be discussed
(collaboration with the Laboratoire des Ponts et Chaussées (Paris)).

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.
Some platoons composed of cars very close to each
other and moving almost as a solid block could
be seen, involving up to 67 vehicles.

I have made the proposal that the response of a highway system
to a local perturbation (onramp) 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 onramp.
The methodology was illustrated on a cellular automata model,
but could be generalized to any simulator, including the commercial ones.
