A multiple vehicle collision 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 pile-ups have involved more than a hundred vehicles.

What does piling up mean?

pile up. 1. Accumulate, as in The leaves piled up in the yard, or He piled up a huge fortune. In this idiom pile means “form a heap or mass of something.” [

What does pile mean slang?

US, informal. : to join other people in criticizing something or someone in usually an unfair way After the first few negative reviews, all the other critics started piling on.