 As the field received the green flag, Steve Krisiloff, on the inside of the third row, developed engine trouble and slowed down, producing a traffic jam on the main straightaway as the rest of the cars accelerated.Walther, forced to his right by drivers taking evasive action in front of him, touched wheels with Jerry Grant and was catapulted over the wall and into the fence above it.Walther maintained that he was hit from behind, forcing him into Grant, but this claim is not supported by films of the crash and is not widely accepted by other drivers.