Greyhound, the largest bus company in North America, may not be enforcing its own safety limits for driver fatigue, according to a new CNN investigation.
That investigation was prompted by a 2013 bus crash in Pennsylvania in which one person died and several more were injured. The crash happened around 1:30 a.m. while the bus was making the 460-mile run from New York to Cleveland. Passengers think the driver fell asleep at the wheel, according to CNN.
The media outlet found that Greyhound drivers -- who transport some 18 million passengers a year -- frequently drove for unsafe lengths of time, often through the night.
Driver fatigue is linked to 36 percent of all fatal intercity bus crashes, making it the number one cause of such crashes, according to a 2009 study from the U.S. Department of Transportation.
Greyhound's rule book states that drivers are supposed to stop every 150 miles (about two to three hours on a highway) to stop, stretch, walk around and check the bus tires. But this is just a guideline, CNN reports, and it's not enforced.
A Greyhound spokesperson refused to comment to The Huffington Post due to an ongoing internal investigation. But Greyhound CEO David Leach said in a deposition, obtained by CNN, that drivers were expected to use their "best judgment" whether they were too tired to drive.
A Huffington Post investigation into the regulation of truck drivers turned up similar problems: Truckers get notoriously little sleep. They have a high risk of obstructive sleep apnea -- about 28 percent, according to one study, compared to two to four percent risk for Americans overall -- and often work very long shifts that mess with their bodies' circadian rhythms. Despite this, the trucking industry has been loath to reform its work schedules for drivers.
It remains to be seen how Greyhound and the commercial bus industry will react to CNN's findings.
Of course, drowsy driving isn't just an issue for truckers and bus operators. Surveys suggest that millions of Americans have nodded off behind the wheel, and sleepy drivers are linked to 328,000 crashes each year.