US Patent 10026319 Collision warning system

A collision warning system including a vehicle with a first sensor configured to detect an exit condition, a second sensor configured to detect a collision condition, an external warning signal system configured to emit a warning signal to warn a vehicle occupant about the collision condition, the external warning signal system includes at least one warning device configured to emit the warning signal, and a controller configured to communicate with the first and second sensors and to control the at least one warning device in response to the collision condition.