After a fifteen month-long investigation, the National Transportation Safety Board has determined that bus driver fatigue was the main factor contributing to that horrific crash that killed 15 people in the Bronx in March, 2011. Investigators determined that the driver, Ophadell Williams, barely slept in the three days leading up to the World Wide Travel bus crash, except for brief naps. Federal guidelines limit passenger-bus drivers to 10 hours on the job a day, but log books are frequently fudged, and World Wide Travel had been cited several times for log book discrepancies.

The report (you can read a summary here) did not conclude that Williams fell asleep. But investigators believe the crash would never have happened had the driver been rested. The NTSB says: "The driver was impaired by fatigue at the time of the accident due to sleep deprivation, poor sleep quality, and circadian factors; and his lack of evasive braking or corrective steering action as the bus drifted off the roadway was consistent with fatigue-induced performance impairment.

"Had the motorcoach been equipped with in-vehicle technologies such as a lane departure warning system or drowsy driver warning system, the driver would have been alerted and had the opportunity to stop driving before the accident occurred." Instead, the bus struck a guardrail and flipped onto one side before colliding with a vertical highway signpost, which ripped through the passenger compartment along the base of the windows as the vehicle slid forward.

Speed was also a factor. The report finds that the bus was traveling as fast as 78 mph in the minute leading up to the crash, and was traveling at least 64 mph in the 50 mph speed zone for at least 10 seconds before it struck the guardrail. Using a computer simulation, investigators found that if Williams had been going the speed limit, the bus might not have overturned and he may have been able to steer away from the guardrail.

"Fatigue and speed are an especially lethal combination," says NTSB Chairman Deborah A. P. Hersman. "Unfortunately, in investigation after investigation, we are seeing the tragic results of fatigue, which can degrade every aspect of human performance." The NTSB made a total of 16 safety recommendations in the report, such as requiring bus companies to obtain a 10-year driving history for all prospective commercial vehicle drivers, and evaluating the effects of seat spacing and armrests as a factor for potential injury.

Williams has pleaded not guilty to charges of manslaughter and criminally negligent homicide, and his lawyer had declined to comment. World Wide was shut down after the accident, but the AP reports that "the company's employees, buses and other assets were transferred to a closely related company with similar ownership, Great Escapes." Investigators say that company continues to operate.