WASHINGTON – The National Transportation Safety Board has determined that a fatal 2016 collision between a motorcoach and tractor-trailer truck near Palm Springs, Calif., was likely caused by undiagnosed obstructive sleep apnea and inaction by a driver due to fatigue.
NTSB also said inadequate plans by the California Department of Transportation for stopping highway traffic near utility work contributed to the accident.
In the early-morning darkness of Oct. 23, 2016, the motorcoach was traveling at highway speed on Interstate 10 when it crashed into a stopped truck, resulting in the death of the motorcoach driver and 12 motorcoach passengers.
The truck, operated by Tri-State Collision LLC, and other traffic had been stopped on the highway by police because of utility work. When traffic resumed, the truck did not move.
The 47-passenger motorcoach, operated by USA Holiday, struck the rear of the truck two minutes later, intruding about 13 feet into the truck trailer and pushing it 71 feet forward.
NTSB determined the probable cause of the crash was Caltrans’ inadequate transportation management plan for stopping traffic, which resulted in a hazardous situation in which law enforcement did not detect the truck’s lack of movement following the traffic break and did not provide any advance warning to the bus driver of the potential for stopped traffic ahead.
The board also determined the truck driver did not resume driving after the traffic stoppage because he most likely fell asleep due to fatigue related to his undiagnosed, moderate-to-severe obstructive sleep apnea.
The truck driver, 51-year-old Bruce Guilford, was arrested in Georgia in October by a U.S. Marshals Service task force. He had been charged a day earlier in California with vehicular manslaughter and reckless driving.
Despite the fact the truck driver was severely obese and at a high risk for obstructive sleep apnea, he had not been tested for the condition, NTSB said in a news release.
And, the board said, “although the Federal Motor Carrier Safety Administration Medical Review Board has developed guidance for screening for obstructive sleep apnea, FMCSA has not disseminated this guidance to the medical examiners it certifies to perform commercial driver’s license medical examinations.”
Sleep apnea, often undiagnosed, is characterized by shallow or interrupted breathing during sleep and can leave sufferers fatigued.
The Obama administration had been considering requiring commercial motor vehicle drivers and railroad engineers to be screened for sleep apnea, but the Trump administration scrapped the effort in August.
NTSB’s investigation also revealed the bus driver had untreated diabetes, but the FMCSA-certified medical examiner did not diagnose the condition or refer the driver for further testing despite a positive glucose urine test during the driver’s medical certificate examination.
NTSB also found that the bus driver did not take actions to avoid the crash because he, too, was likely fatigued and did not expect to encounter stopped traffic.
“In this crash, not one but two commercial vehicle drivers – people who drive for a living – were unable to respond appropriately to cues that other motorists acted on,’’ said NTSB Chairman Robert L. Sumwalt. “Federal and state regulators, commercial motor carriers and professional drivers can do better. Given the stakes, they must do better.’’
The board issued eight safety recommendations including assessing forward collision avoidance systems in commercial vehicles and requiring new motorcoach and bus designs to include a secondary door for use as an additional emergency exit.