Multiple-vehicle collision

A multiple vehicle collision (colloquially known as a pile-up, multi-car collision, multi-vehicle collision, or simply a multi) is a road traffic collision involving many vehicles. Generally occurring on high-capacity and high-speed routes such as freeways, they are one of the deadliest forms of traffic collisions. The most disastrous pileups have involved more than a hundred vehicles. A chain collision can be defined as "an accident involving 3 or more vehicles in which one vehicle has only rear impact damage (i.e., the "lead" vehicle); one vehicle has only frontal damage; and all other vehicles have frontal and rear impact damage (these are the "middle" vehicles)". In Great Britain, statistics are available on the number of vehicles involved in crashes. In 2013, there were: 42487 single vehicle crashes, 82429 dual vehicle crashes, 13744 crashes involving three or more vehicles (%) for a total of 138660 reported crashes. In crashes with three or more vehicles there were 228 motorists killed and 19 pedestrians killed. In 2020, there were: 25730 single vehicle crashes, 57392 dual vehicle crashes, 8077 crashes involving three or more vehicles (%) for a total of 91199 reported crashes. In crashes with three or more vehicles there was 200 motorists killed (% of all motorists killed) and 17 pedestrians killed (% of all pedestrians killed). Pile-ups generally occur in low-visibility conditions as drivers on freeways are sometimes caught out by driving too close to the vehicle in front and not adjusting to the road conditions. Chain-reaction crashes can also occur in conditions of good visibility, when black ice or other road hazards are encountered unexpectedly as drivers round a curve or crest a hill. Multiple vehicle collisions can also occur when a third vehicle is too close to the initial collision to avoid hitting one or both of the vehicles. Due to the high traffic speeds on the road, if one car develops a problem and suddenly halts, those behind it cannot stop in time and may hit it.