  We derive the exact formula for thermal-equilibrium spacing distribution of
one-dimensional particle gas with repulsive potential V(r)=r^(-a) (a>0)
depending on the distance r between the neighboring particles. The calculated
distribution (for a=1) is successfully compared with the highway-traffic
clearance distributions, which provides a detailed view of changes in
microscopical structure of traffic sample depending on traffic density. In
addition to that, the observed correspondence is a strong support of studies
applying the equilibrium statistical physics to traffic modelling.
