Background
On September 30, 1955, actor James Dean was killed in a two-vehicle accident near Paso Robles, CA. Dean was killed, but his passenger and the driver of the other vehicle survived. The police reported that speed contributed to the cause to the accident and that Dean was traveling over 65 mph at the time of the impact. In 1992, while working on the NBC television series “What Happened?”, Exponent’s engineers were asked to look into the accident.
Our Work
The vehicles that were involved were not available for review, so our engineers used photos from the accident scene to review crush damage, the police report and photogrammetry techniques to survey the accident scene. This information was used in our analysis to determine the speeds, steering and braking of Dean’s Porsche Spider and a Ford Sedan. The accident happened about 6pm in the evening, so our visibility consultants reviewed any potential impact that the setting sun might have contributed.
Using sophisticated accident reconstruction computer simulation programs, Exponent ran various combination of speed, braking and steering to see how closely they matched the actual damage to the vehicles. Visibility analysis indicated that the setting sun would not have caused an issue for either driver. The skid marks that we were able to determine from the police photos appear to indicate that the Ford driver might have first thought he could beat the Porsche to the intersection and make his turn and then changed his mind and applied his brakes hard enough to leave the marks that are seen in the accident photos. The damage patterns, skid marks and Exponent’s computer simulation show that Dean was traveling between 55-60 mph at the time of the accident.
So why so some people believe that Dean was speeding at the time of the accident? Well, a few hours before the accident, Dean was given a speeding ticket. If you calculate the amount of time that elapsed between the time he was given the ticket and the accident as well as measured the distance between the two locations, he would have been traveling about 70 mph. Maybe he saw the Ford coming toward him and thought the black-and-white car was a police car and decided to slow down. No one will ever really know.
