BOWLING GREEN, Va. (AP) - Energy drinks, coffee and even talking on his cell phone weren't enough to keep bus driver Kin Yiu Cheung awake after a night on the road.
About an hour before dawn, nearly seven hours into his shift, Cheung dozed off as his bus carrying 59 passengers barreled northward on Interstate 95 in Virginia on May 31, according to court documents.
The bus veered off the highway. When Cheung tried to swerve back onto the road, the bus hit an embankment and overturned, authorities say. Four passengers were killed and dozens more injured. Attorneys for Cheung, who remains in jail without bond, have called the wreck a "tragic accident."
Prosecutors have charged Cheung, 37, of Flushing, N.Y., with four counts of involuntary manslaughter. But sleep scientists, safety advocates and labor leaders say the roots of the accident lie with an industry whose economic model often results in drivers on the road with too little rest and at hours when their bodies naturally crave sleep.
"The consequence is an entire industry populated by people not getting enough sleep," said Larry Hanley, president of the Amalgamated Transit Union, which represents drivers at Greyhound and other companies.
Studies show that between 13 percent and 31 percent of commercial vehicle crashes are due to driver fatigue, according to the National Transportation Safety Board.
Recent deadly crashes involving motor coaches - large buses that travel between cities, like the vehicle Cheung was driving - have heightened concern about driver fatigue. In March, a bus returning passengers to New York's Chinatown after a night of gambling ran off an elevated highway and hit a utility pole, shearing off its roof.
Fifteen passengers were killed and many more injured. The driver has said he was awake and alert, but passengers told police the bus was swerving. A lawsuit filed by one passenger claims the driver was asleep.
The Federal Motor Carrier Safety Administration, which oversees the nation's estimated 4,000 passenger bus companies, had flagged the bus company in the New York crash, World Wide Travel, for possible extra scrutiny due to violations involving driver fatigue.
Sky Express Inc. of Charlotte, N.C., which employed Cheung to drive from North Carolina to New York, had been cited for 46 violations involving driver fatigue rules over two years, ranking it in the bottom 14 percent of motor carriers.
Passengers on the bus that crashed overheard Cheung complaining in a cell phone call that he was tired and that he didn't have much turn-around time between trips, according to a court affidavit.
Federal officials were in the process of shutting down the company at the time of the crash. A timeline released by the Department of Transportation showed Sky Express would have stopped operations the weekend before the May 31 crash if regulators hadn't extended their review an extra 10 days.
Bus industry officials say motor coaches have a good safety record. The popularity of motor coach travel has soared over the past decade, in part because it's relatively inexpensive. The industry transports an estimated 750 million passengers annually in the U.S., roughly equivalent to the domestic airline industry - yet only about 20 passengers a year are killed in accidents.
Pete Pantuso, president of the American Bus Association, said fatalities are primarily the fault of a handful of small operators who ignore safety regulations to cut costs. When the government orders them to shut down, they reopen under a new name or in a new location. The problem is so common they are known in the industry as reincarnated or chameleon carriers.
That's what federal officials say Sky Express did following the crash. Regulators ordered the company to shut down hours after the accident. But Sky Express continued to operate using two other names, 108 Tours and 108 Bus. The department issued a cease and desist order.
Last Thursday, federal inspectors shut down a company in East Point, Ga., that was operating its three buses under two different names from the same location. JCT Motor Coach, also known as JT's Travel & Charter, made no effort to comply with regulations limiting drivers' hours, among a raft of other safety violations, according to the order shutting the carrier. The company didn't even have a system for recording drivers' hours, it said.
James Turner, the company's manager, did not return a phone message left Friday by The Associated Press.
Hanley, with the drivers' union, blamed the problem on deregulation of the bus industry in the early 1980s. The result, he said, has been a phenomenal growth in cut-rate bus companies, driving down ticket prices. As a result, bus companies have slashed driver pay and benefits to stay competitive.
It's not uncommon for companies to juggle schedules up until the last minute, calling drivers into work with as little as an hour's notice. Even if a driver feels short on sleep, there is strong incentive to make the trip - drivers who don't take an assignment go to the bottom of the call list, Hanley said, and most drivers are paid only for trips they make. It's also common for drivers to work second and third jobs because the pay is so low, Hanley said.
Federal regulations allow bus drivers up to 10 hours behind the wheel followed by a minimum of eight hours rest. That adds up to 18 hours, making it legal for a driver to work an entire shift and start a second shift all in one 24-hour period, said Greg Belenky, a sleep expert at Washington State University and former neuroscience division director at the Walter Reed Army Institute of Research.
Bus drivers also have a 15-hour window in which they can be considered on duty. For example, they could drive five hours, wait five hours at a terminal to pick up passengers, and then drive five more hours. That 15-hour window can be extended if drivers have off-duty breaks in between.
Rules differ for truck drivers, who are permitted to drive for 11 straight hours after 10 hours off. They have a hard 14-hour window, which can't be extended.
Even bus companies that want to abide by rules on rest breaks and driving hours may find it hard to ensure their drivers are taking advantage of their time off to sleep.
"There's a lot of pressure for them to keep to their schedules and sometimes those schedules are hard to meet," said Henry Jasny, general counsel for Advocates for Highway and Auto Safety, a safety and consumer group supported by the insurance industry.
Fatigue can be a problem for any driver on the road overnight, especially between the hours of 4 a.m. and 6 a.m. when the human body's circadian rhythms - physical and behavioral changes that respond to light and darkness - are telling the brain to sleep, according to sleep experts.
Cheung's driving log said he finished a driving shift at 5:45 a.m. on May 30, awakened at 6 p.m., and started his next shift at 10 p.m., police said. The bus left Greensboro, N.C., at 10:30 p.m. and made several stops before crashing shortly before 5 a.m. the following day.
"No matter how much sleep you have had, no matter how young you are, that time of day is extremely dangerous to drive a motor vehicle," said transportation and public safety consultant Darrel Drobnich, an expert on driver fatigue.
The problem is exacerbated by a high rate of obesity and sleep apnea among commercial drivers, he said.
One of NTSB's top safety recommendations has been to equip bus and trucks with devices that keep track of how many hours drivers are on the road. The recorders, which would replace paper driving logs, are a way to enforce limits on drivers' work hours.
A proposed Transportation Department rule would require companies to equip vehicles with the recorders, but the rule isn't final.
More frequent rest stops so drivers can grab 20- to 30-minute naps might help, Belenky said, but that would also lengthen bus trips and possibly cost companies customers.
Putting a second driver on the bus to share the driving might also help if bus companies don't balk at the cost.
But then there's no guarantee a second driver would be able to stay awake, either.