The driver of a Charlotte-based discount bus to New York that crashed and killed four riders was sentenced to six years in prison on Wednesday, but bus companies with bad safety records still operate from Charlotte despite a federal crackdown last year.

Kin Yiu Cheung, of New York was convicted last year of four counts of involuntary manslaughter in Caroline County, Va., after the Sky Express bus he was operating went off the side of Interstate 95 in the early morning hours and overturned in 2011. A judge imposed a 40-year sentence, with 34 years suspended.

Police said during the trial that Cheung admitted he fell asleep at the wheel.

“Each day of my life is haunted by this memory … and I want to apologize to all the passengers,” he told the court Wednesday.

The wreck highlighted gaps in the intercity bus safety net. Sky Express had been ordered off the roads before the crash due to a string of safety violations, but regulators had given the company an extension at the time of the wreck.

Following the crash, and several other fatal bus wrecks that year, the federal government conducted a widespread crackdown, ordering 26 unsafe bus companies to shut down. It was the largest bus-safety enforcement action to date.

But federal records recently obtained by the Observer through the Freedom of Information Act show two companies operating in Charlotte have ties to Sky Express. Those companies, Ming An and General Bus, also have safety records among the worst in the nation. Neither responded to phone and email messages seeking comment Wednesday.

Duane DeBruyne, spokesman for the Federal Motor Carrier Safety Administration, wouldn’t comment on the particular companies operating in Charlotte. He said the FMCSA has increased its oversight of bus companies dramatically over the past two years. The agency has shut down 50 unsafe bus companies since 2010, compared with four in the preceding decade.

Steve Keppler, executive director of the Commercial Vehicle Safety Alliance, a group of law enforcement and bus-industry officials, said “there’s been a concerted effort on more oversight” since the Sky Express crash. “We’re making some progress,” he said. “I wouldn’t say we’re there yet.”

He pointed to new powers regulators gained in the federal transportation bill passed last summer. That measure increased fines for continuing to operate a bus line after being ordered to shut down from $2,500 to $25,000 per day. It also mandated that new bus lines undergo a safety evaluation within 120 days of starting operations and allows the government to impound buses from companies deemed an imminent hazard.

Authorities still lack some crucial powers, though, Keppler said. For instance, unlike trucks, buses can’t be stopped for a random roadside inspection.

Bus safety has been a growing issue as the popularity of intercity bus travel increased during the economic downturn. Researchers at DePaul University, which studies bus service, said daily bus operations by discount city-to-city operators grew from 798 to 1,052 between 2011 and 2012. And the bus industry estimates riders now take some 750 million intercity bus trips a year in the U.S.

Meanwhile, bus companies that grow out of companies that are supposed to be shut down – known as “chameleon” or “reincarnated” carriers – continue to ply the nation’s roads, despite the government’s new powers to regulate the industry.

Two companies in Charlotte show the close ties bus companies can have when one is ordered off the road by government regulators.

General Bus

After the Sky Express crash in May 2011, federal regulators ordered its buses off the road. But no one seized the company’s buses. Four months later, New York-based General Bus began ferrying passengers from the old Sky Express stop on Independence Boulevard to its former drop-off spot in Manhattan’s Chinatown.

General Bus still makes those daily runs, with tickets listed for $60 online. The company’s last safety review was in February 2012, and the company is allowed to operate with no current safety rating from the federal government.

That review, obtained recently by the Observer, shows that four of General Bus’ seven motor coaches were purchased from Sky Express after the company was ordered to shut down, and five of the 10 drivers General Bus employed worked for Sky Express.

“The routes and schedules currently conducted by General Bus Inc. very closely resemble the routes and schedules formerly conducted by a carrier known as Sky Express,” the report noted.

General Bus had gross revenue of $550,000 for fiscal 2011, federal records show. After the safety review concluded, federal regulators fined General Bus $2,250 in May 2012 for safety violations, including failing to require drivers to create proper vehicle inspection reports.

Federal safety records show General Bus has an unsafe driving record that is worse than 99.7 percent of companies in the nation, and a driver fitness record worse than 77.3 percent of all carriers. In the last two years, the company has been cited seven times for speeding 11 mph or more over the speed limit, four times for drivers not being able to speak English, and for a driver possessing, using, or being under the influence of alcohol less than four hours before going on duty.

Ming An

Another company that the government identified as having ties to Sky Express is New York-based Ming An, which offers daily overnight bus trips from west Charlotte’s Queen City Drive to Canal Street in Chinatown.

In a December 2011 federal safety review, inspectors found Ming An had bought a bus from Sky Express and employed its drivers. Federal regulators also uncovered links between Ming An and five other companies, including two besides Sky Express that had been ordered to shut down.

Regulators fined the company $2,250 for driver record and inspection violations, payable in four payments, in January 2012. The review shows Ming An had gross revenue of $558,469 in 2010, the most recent year available.

State records show the company applied for a certificate of authority to do business in North Carolina in August 2012, listing a house on Idlewild Road near Independence as its address. Sky Express used the same house as its corporate address in January 2011, N.C. Secretary of State records show. Jing Han, who was listed as a corporate official with Sky Express before the company was shut down, owns the house being used by the Ming An company.

“I own the house, but I have nothing to do with the company,” Han told the Observer on Wednesday. She said she wasn’t sure which company was using the house, but that she believed bus drivers use it to sleep. She doesn’t think they are affiliated with Sky Express, Han said, because when she goes to pick up the rent there are now different people there.

Federal safety records show the Ming An company has a driving safety record worse than 99.8 percent of bus companies in the nation, and a driver fitness record worse than 98.9 percent of companies. The company has been cited five times in the past two years for speeding 15 mph or more over the speed limit, four times for drivers not speaking English, and for drivers without a commercial license, without a medical certificate, and who were disqualified from operating commercial vehicles.

The company has had two compliance reviews since 2010, and is currently allowed to operate, with a “conditional,” or probationary, safety rating from the federal government. The Associated Press contributed.