A new study has reported that sleep apnea in truck drivers can be particularly dangerous.

According to a press release by the American Academy of Sleep Medicine, truck drivers who fail to get treatment for obstructive sleep apnea “are a public safety threat on U.S. roadways.” Weighing 20-30 times as much as passenger cars and needing 20-40 percent more road space to stop than cars, trucks are already a significant threat to other vehicles on the road, killing 3,660 people in 2014.