A report released by the Governors Highway Safety Association (GHSA) indicates that drowsy drivers are becoming a growing threat to public safety and an issue that costs U.S. taxpayers as much as $109 billion every year.

Based on research contributed by the American Automobile Association (AAA), the National Transportation Safety Board (NTSB) and the National Highway Traffic Safety Administration (NHTSA), the GHSA report indicates that as many as 328,000 accidents annually occur on U.S. roads as a result of drowsy-driving. In a typical year, 109,000 injuries and 6,400 deaths are attributed to those crashes.

Likening sleep impairment to drunk driving, the GHSA’s Jonathan Adkins maintains that the problem is more severe than the association anticipated.

“We’re literally falling asleep, comatose, behind the wheel and we’re crashing and we’re hurting ourselves and killing ourselves and others,” he said.

The GHSA report concluded that drowsy driving is largely the result of fatigue from Americans overworking without taking sufficient breaks and providing themselves with opportunities to relax. The association also found that teenagers and young adults were involved in more than 50 percent of all drowsy-driving crashes, in part due to inexperience behind the wheel and biological changes.