Multiple-vehicle collision in traffic flow by a sudden slowdown

We study the multiple-vehicle collision when a vehicle decelerates suddenly in a single-lane traffic flow. The extended optimal velocity model is used for the vehicular motion to take into account the relative velocity. If a vehicle slows down suddenly and the following vehicle does not decelerate successfully, it crashes into the vehicle ahead with a residual speed and the crash may induce more collisions. The number of crumpled vehicles depends on the initial headway, the sensitivity, the initial velocity, and the relative velocity. We derive the region map (phase diagram) for the multiple-vehicle collision. The dependence of the multiple-vehicle collision on the density, sensitivity, and relative velocity is shown.