A state Transportation Department review finds a "sudden weather event" caused a flash freeze of black ice before a deadly 40-vehicle wreck on the New Jersey Turnpike.

DOT spokesman Stephen Schapiro tells NJ.com the review found no fault in road operations because crews were salting. However, the report recommends officials check new potions of a widening project to identify areas that may pose a greater risk for icing.

DOT Commissioner Jamie Fox ordered the review after state police said ice was a factor in a series of crashes in Cranbury and Bordentown on Feb. 9. The crash involved four tractor-trailers, two box trucks and a fully-loaded bus. Transportation Commissioner Jamie Fox says a "flash freeze of black ice" is to blame for the crash. 

News 12 New Jersey obtained 911 calls made by drivers involved in the pileup. Many of the drivers told emergency dispatchers that several vehicles, including a tractor-trailer were involved in a crash. They urged dispatchers to send police and emergency medical personnel to the scene.

Twenty-one vehicles were involved in multiple accidents on the inner roadway and 19 were involved in crashes on the outer roadway.

One man became trapped in his car and died. Dozens of motorists were injured.

AP wires helped attribute to this article.