Incollection,
Physics of the city: an exponential car mobility law.
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)
Abstract
We show an exponential law for the car dynamics in urban contexts, deduced
analyzing a very large set of GPS data. This law appears to be common for very
different urban systems, from the size of a town to that of a metropolis, and
we think that it could be a universal city law, valid for every urban car
dynamics. We describe series of global data sufficiently long to define the
dynamical driving car behaviour. More precisely a GPS system has been set up
on the single car for insurance reasons, measuring position and velocity. The
data are recorded every time the engine is switched on or off, and during
the travel at a distance of about 2 km. We have found an exponential law for
the travel lenght distribution of urban car mobility (fig. 1). We consider the
cases of Senigallia (small town), Bologna (middle town) and Roma (metropolis)
to show the universal character of the law. We discuss some implication of
this law, and in particular its relation with the asystematic mobility
pointed out by recent sociological studies.
