Sleeping less than seven hours raises risk of collision says AAA

Published: December 9, 2016

Updated: July 24, 2018

Author: Luke Jones



The AAA Foundation for Traffic Safety has issued a recent report that discusses the dangers of driving when tired or low on sleep. The traffic safety group says drivers who have slept fewer than seven hours in the past 24 hours have a “significantly elevated” risk of being in a collision.

Washington, D.C.-based AAA Foundation for Traffic Safety published the report on Dec. 6. In the study, the group researched more than 4,500 collisions through the United States, all of which happened around 10 years ago.

“The estimated crash risk associated with driving after only 4-5 hours of sleep compared with 7 hours or more” is similar to the U.S. National Highway Traffic Safety Administration’s “estimated of crash risk” associated with driving with blood alcohol level of .08% “or slightly over,” AAA suggested in the report.

“Symptoms of drowsy driving can include having trouble keeping eyes open, drifting from lanes or not remembering the last few miles driven,” AAA added. “However, more than half of drivers involved in fatigue-related crashes experienced no symptoms before falling asleep behind the wheel.”

Title Acute Sleep Deprivation and Risk of Motor Vehicle Crash Involvement, the report was compiled by AAA senior research associate Brian Tefft. In creating the study, the foundation analyzed collision data from the NHTSA National Motor Vehicle Crash Causation Survey. The survey “comprised a representative sample of police-reported crashes that occurred between July 2005 and December 2007.”

The collisions taken into account happened between 6:00 a.m. and midnight and involved at least on car, van, minivan, pickup truck, or sport utility vehicles. Each of the studied crashes were investigated and medical professionals were involved.

The results “indicate that there is a significantly elevated crash risk” if a driver has slept less than seven hours in the previous 24. Just sleeping one of two hours less than normal can increase the risk of collision. However, sleeping a minimum of seven hours, the data starts to change.

Sleeping less than seven hours gives drivers a 1.3 times more chance of collisions. Motorists who slept five and six hours had 1.9 times the crash rate. Those who slept four to five hours had 4.3 times the crash rate. Drivers who had less than four hours had 11.5 times the crash rate.