Adopted: October 17, 1973
FOLLOWED BY PROPYLENE CARGO-TANK EXPLOSION
NEW JERSEY TURNPIKE, EXIT 8
SEPTEMBER 21, 1972
NTSB Number: HAR-73/04
NTIS Number: PB-225032/AS
PDF Document (2.71 MB)
This report describes and analyses a series of collisions which occurred in the northbound lanes of the New Jersey Turnpike on September 21, 1972. A northbound Greyhound bus was sideswiped by an overtaking tractor-semitrailer which was carrying propylene. The tractor-semitrailer then overrode the median guardrail, jackknifed, and overturned in the northbound lanes. Two persons in an automobile which collided with the overturned cargo-tank semitrailer were killed in the collision or in the fire which followed. About 25 minutes after the collisions, the cargo tank exploded; sections of the tank rocketed 1,307 feet northeast and 500 feet southwest of the point of overturn. Twenty-eight persons were injured in the explosion.
The National Transportation Safety Board determines that the probable cause of the initial collision was the evasive steering and skidding of the bus into the path of the overtaking tractor-semitrailer. Override of the median guardrail by and subsequent overturn of the tractor and the semitrailer were caused by the inability of the median guardrail to resist the forces generated by the tractor-semitrailer.
In the report, the Board also determines the cause of the initial and secondary fires at the cargo-tank semitrailer as well as the cause of the explosion.