A new study shows drowsy driving, where those behind the wheel are too tired to safely operate a vehicle, is much more widespread than previously estimated.
In fact, researchers suspect tired drivers are responsible for roughly 1 out of every 10 crashes.
"Drowsy driving is a bigger traffic safety issue than federal estimates show," said David Yang, executive director of the AAA Foundation for Traffic Safety. "Drivers who don't get enough sleep are putting everyone on the road at risk."
AAA reached that conclusion after researchers monitored the driving habits of more than 3,500 people for several months. Using dashboard cameras and other equipment, the researchers tracked drivers around the United States between October 2010 and December 2013.
Those 3,500 drivers were involved in more than 700 crashes. Drowsiness was determined to be a factor in up to 9.5 percent of those accidents. In addition, more than 10 percent of the accidents that resulted in property damage, airbag deployment or injury involved tired drivers.
The percentages are far higher than what the federal government has estimated as the impact of drowsy driving, which it puts at 1 to 2 percent of all vehicle crashes.
The AAA study is significant because it's the most in-depth study ever conducted on U.S. drivers.
It also comes at a time when researchers in many fields are examining the impact of Americans failing to get enough sleep. A recent survey by the AAA foundation found 29 percent of those questioned admitted to driving, at some point in the past month, when they were so tired they had a hard time keeping their eyes open.
The new research shows drowsy driving is as common among men as women behind the wheel. Also, almost 70 percent of the accidents documented happened during the day. More than half of those crashes involved drivers 16 to 24 years old.
In recent years, as safety advocates have focused on eliminating or reducing distracted driving, the problem of tired drivers has been given relatively little attention. One reason may be that it's hard to measure how many accidents are caused by drivers who have closed their eyes or nodded off when behind the wheel.
The issue is one trucking companies are acutely aware of and it has prompted some to use cameras in the cabs of semis to monitor drivers. Seeing Machines, which is based in Australia, uses in-cab cameras to track the eyes and faces of drivers. When the software detects a driver may be getting drowsy, the system sounds an alarm and the driver's seat vibrates to ensure the driver is awake.
Seeing Machines cameras are incorporated in General Motors' new Super Cruise driver-assist system, which is featured in the 2018 Cadillac CT6.
AAA hopes its research raises awareness of just how dangerous drowsy driving can be, not only on long road trips, but also on shorter, everyday trips.
"Missing just two to three hours of sleep can more than quadruple your risk for a crash, which is the equivalent of driving drunk," said Jake Nelson, director of traffic safety advocacy and research at AAA.