Editing Multiple-vehicle collision (section)

== Causes ==
Pile-ups generally occur in low-visibility conditions as drivers on freeways are following too closely and [[Situation awareness|unable to adjust]] to road conditions.

Chain-reaction crashes can also occur in conditions of good visibility, when [[black ice]] or other [[road hazard]]s are encountered unexpectedly as drivers round a curve or crest a hill.<ref name=Abel/>

Multiple vehicle collisions can also occur when a third vehicle is too close to an 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, ones behind it cannot stop in time and may hit it. Considering that these roads often have high traffic volumes, more cars are forced into braking and skidding, darting into other lanes and in front of other traffic; more vehicles become involved, creating a [[chain reaction]] effect.

Determining the cause of such collisions is difficult for [[detective|investigator]]s and it is often impossible to tell if [[negligence]] caused the crash. In spite of their frequency, little formal research has been done in the United States regarding their causes.<ref>{{cite news |first1=Larry |last1=Copeland |first2=Paul |last2=Overberg |title=Special cops work to unravel confusing highway pileups |url=https://www.usatoday.com/story/news/2015/02/18/unraveling-multiple-vehicle-pileups/23323989/ |work=[[USA Today]] |date=18 February 2015 |access-date=19 February 2015 |quote=There is little research on why these crashes occur. Neither the [[Federal Highway Administration]], the [[National Highway Traffic Safety Administration]], the [[National Transportation Safety Board]], the [[Insurance Institute for Highway Safety]] nor auto club [[American Automobile Association|AAA]] has researched the phenomena. }}</ref>