Multiple-vehicle collision

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.

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.

Individual vehicles in a multiple-vehicle collision are often hit multiple times at high speed, increasing the risk of injury to passengers who may have survived the first impact with the benefit of now-discharged protective airbags.

A fire in one part of the collision can quickly spread via spilled gasoline and cover the entire crash area.

The destruction and intense heat of fires can also damage roadways, particularly by melting and burning the asphalt or spalling concrete surfaces.

A fiery pileup inside a tunnel is the most serious, as there is little means to escape the poisonous fumes and the confined heat may damage structural supports.

Aftermath of a multi-vehicle collision on the M4 Motorway in Sydney , Australia
Emergency services work on the scene of a multiple vehicle collision in Toronto .