It was one of the most heartrending incidents that unfolded during the Hurricane Rita disaster: A motorcoach evacuating frail elderly residents and staff from a Texas assisted living facility in advance of the storm burst into flames on Interstate 45 near Dallas, killing 23 passengers and injuring 21 others.

Yesterday the National Transportation Safety Board released the findings of its investigation into the tragedy, citing shoddy federal oversight of the motorcoach industry. Bus owner Global Limo Inc. of Pharr, Texas got away with failing to conduct proper vehicle maintenance, pre-trip inspections and post-trip driver vehicle inspection reports, which allowed insufficient wheel bearing lubrication to go undetected and eventually spark the catastrophic fire, NTSB concluded.

The report aimed most of its recommendations at the Federal Motor Carrier Safety Administration, the federal agency charged with reducing crashes, injuries and fatalities involving large trucks and buses.

"We will not cease our efforts to push for change to prevent these kinds of accidents from occurring," NTSB Chair Mark Rosenker said in a statement. "However, unless there is adequate oversight, I am afraid we will continue to see motorcoach accidents that contribute to the unacceptable number of deaths on our nation's highway."

Rosenker expressed concern that the FMCSA had not heeded all of the NTSB's suggestions in the past: Of more than 60 safety recommendations the NTSB proposed in the past eight years, only 26 have been adopted by the motor carrier agency, the Washington Post reports:

"There is outrage when a couple hundred people are killed in aviation fatal accidents, yet you don't seem to see, share or demonstrate the same outrage when 4,300 people die on our nation's highways annually," Rosenker said. "We can make changes here on this board . . . to chip away piece by piece at the 4,300 people who die on highways."

NTSB found that Global failed to retain vehicle maintenance and repair records as required by Federal Motor Carrier Safety regulations, and also lacked a maintenance program to properly service the vehicle. The report concluded that the company's disregard for such a program led to the failure to detect vehicle defects that ultimately led to the deaths.

Contributing to the accident was the FMCSA's ineffective compliance review system, which resulted in inadequate safety oversight of passenger motor carriers, NTSB said. The agency's current process does not effectively identify unsafe motor carriers and prevent them from operating, the NTSB found. Furthermore, the lack of fire-retardant construction materials adjacent to the motorcoach's wheel well fueled the fire's severity.

Last month, a federal court in Texas sentenced Global Limo owner James Maples to five years' probation for mismanaging his fleet and failing to require drivers to fill out inspection reports. Maples was fined $10,000, and his now-closed business was fined $100,000.

A government investigation after the accident also found 168 alleged violations involving four other Global Limo buses. The motorcoach involved in the deadly accident near Dallas had an illegal license plate, and its driver did not have a valid U.S. driver's license.