Cars equipped with the latest safety technology already warn drivers about oncoming cars. Toyota said Friday that it had developed the world’s first system for detecting rear-end collisions before they happen. A radar device is installed in the rear bumper to detect a vehicle approaching from behind. Sensors in the front headrests detect the position of the driver’s and front passenger’s heads, and shift the headrests’ position to reduce the risk of whiplash injury, it said. Hazard lights also start flashing to warn the driver of a possible crash from behind. Source: MSNBC