A moving vehicle may very likely run into accidents. The occurrence rate of accidents would be largely reduced if the driver is warned in advance, even only 0.5 s earlier. For a running vehicle, the driving route within short time before collision has the characteristic of Markov. In this case, the coordinates of position only have to be considered within a short range, rather than the running status during the past long period. Within short period before collision, the driving route can be basically divided into two states: a straight line and a binomial curve. In this paper, a mechanism is proposed for sending collision warning messages to running vehicles.