Fatigue in single car fatal accidents

In a reexamination of 101 fatal single car accidents without any reasonable explanation besides possible intoxication, 50 drivers were found to have been intoxicated with a blood alcohol content (BAC) of more than 0.08 mg% at the time of the accident. Thirty-seven of these accidents happened between 2400 h and 0600 h in the morning and 21 of the drivers were found to be intoxicated. The remaining 64 accidents took place during the rest of the day and 21 drivers were found to be intoxicated. By comparing this apparent over-representation of intoxicated drivers in night-time accidents with that of a control group of no less than 15.923 drivers it was possible to convert this over-representation into a significant under-representation indicating another human accident factor specific to night-time traffic. It is concluded that fatigue is an often overlooked but most obvious cause to an otherwise unexplainable accident in the night-time traffic.