it is a kind of active safety system . on the speedway, when the back vehicle approaches the rear of the forward one, the system will send out collision warning signals to remind the driver of avoiding rear-end collision accident . main investigations and phase fruit : 1 裝有本系統(tǒng)的汽車在高速公路上正常行駛時,當本車車頭接近前車車尾,并有可能與前車發(fā)生追尾碰撞時,該系統(tǒng)就會發(fā)出報警信息,從而提醒本車駕駛員采取制動減速或加速超車等措施以避免與前車發(fā)生汽車追尾碰撞事故。