rear-end
Of a vehicle, to strike (another vehicle) from behind.
rear-end: hitting someone's bumper in traffic
To rear-end a vehicle means to strike it from behind while both are moving in the same direction, or while the struck vehicle is stationary. The impacting vehicle is almost always traveling faster than the one ahead, closing a gap that the driver failed to maintain. In insurance and legal contexts, the rear-ending driver is typically found at fault regardless of circumstances, since traffic law assigns following drivers absolute responsibility for maintaining safe distance.
The severity of a rear-end collision depends on closing speed, vehicle weight, and the design of both vehicles' bumper and frame structures. A 15 kilometer-per-hour impact might produce only bumper damage and whiplash injury; a 60 kilometer-per-hour closing speed often causes crushed crush zones, frame damage, and serious spinal trauma to occupants. Modern vehicles with crumple zones and active safety systems reduce injury risk, but do not eliminate it.
Why it happens and what follows
Rear-end collisions occur most often due to driver inattention, excessive following distance, sudden braking by the lead vehicle, poor road conditions, or equipment failure such as brake fade. Distraction by mobile phones has become a dominant factor since the 2000s. Wet or icy roads dramatically increase rear-end risk by reducing tire friction and braking effectiveness.
After a rear-end collision, the impacted vehicle's occupants commonly suffer acceleration-deceleration injury, particularly whiplash to the neck and head. The struck vehicle may suffer frame misalignment that persists long after cosmetic repair. Insurance adjusters treat rear-end claims as straightforward liability cases, though disputes arise when multi-vehicle pile-ups or comparative negligence claims complicate the facts.
The term is also used as a noun: "a rear-end" describes the collision event itself or the damage pattern it produces. In shop and repair contexts, technicians distinguish rear-end impact damage from side-impact and frontal damage because the repair strategy, parts sourcing, and alignment procedures differ significantly.