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Identification of the “at fault” driver in a highway crash is the usual goal of an investigating police officer. This is understandable since determining blame in order to issue citations or make felony arrests are an essential part of law enforcement. This approach, however, suggests that only one driver is responsible for an accident and is certainly not conducive to identifying other causal factors.

 “Driver error” should not, in my opinion, be the end of an investigation, but the beginning of a search by the investigation/reconstruction/analysis team for other more subtle interactive mechanisms that may have contributed to the accident.

A common example of multiple driver involvement occurs when a car turns left and is struck by an oncoming vehicle. The turning driver is cited for “failure to yield,” thus ending the investigation, even though further analysis might reveal that the other driver could have avoided the collision if attentive or driving at a safe speed.

Sub-standard highway design features and signage are common contributors to “driver errors.” Inconsistent design features, such as left-hand exits from freeways or sudden lane drops are common contributing factors. Driver expectations are important. Closely placed signs that require rapid decisions frequently lead to driver mistakes.

Darkness and oncoming traffic can combine to create a trap for responsible drivers that can lead to “driver error” accidents. At any speed, oncoming headlights produce a relative dark spot adjacent to approaching vehicles that can obscure roadway hazards. Since low beams are required by law when facing oncoming traffic, traveling above 30 or 35 mph results in drivers over-driving their headlights. By the time they see a roadway hazard or pedestrian, there is insufficient time to avoid a collision. These are just a few of the many driver/highway interactive factors that are important accident causation factors.

A future discussion of this topic can be found in Highway Accidents: Investigation, Reconstruction and Causation available at: Information about the book and author is available at: