  We consider a one-dimensional stochastic reaction-diffusion generalizing the
totally asymmetric simple exclusion process, and aiming at describing single
lane roads with vehicles that can change speed. To each particle is associated
a jump rate, and the particular dynamics that we choose (based on 3-sites
patterns) ensures that clusters of occupied sites are of uniform jump rate.
When this model is set on a circle or an infinite line, classical arguments
allow to map it to a linear network of queues (a zero-range process in
theoretical physics parlance) with exponential service times, but with a twist:
the service rate remains constant during a busy period, but can change at
renewal events. We use the tools of queueing theory to compute the fundamental
diagram of the traffic, and show the effects of a condensation mechanism.
