Highway safety is always a critical issue. A variety of sensors are employed in a vehicle for reducing traffic accidents, but it is useful only within the sensor range of this single vehicle. The earlier the driver notices the dangerous situation, the longer the response time is available to the driver. Dedicated Short Range Communications (DSRC) is a good medium for inter-vehicle communications to periodically exchange static and dynamic parameters, and for each vehicle to maintain a map of its surrounding vehicles. The cooperative collision prediction and warning mechanism (CCPWM) will inform the driver of any potential risk to prevent accidents. A Highway Traffic Simulator (HiTSim) with DSRC-based CCPWM equipped on each vehicle was developed for simulating highway traffic and evaluating the probability of accidents. The results demonstrate that the vehicle with DSRC-based CCPWM will increase the time available to the driver to respond and therefore the vehicular safety.