A federal safety board has finalized a report blaming undiagnosed sleep apnea and poor traffic management on a deadly bus crash in California last year.
The National Transportation Safety Board (NTSB) released its final report on Tuesday outlining why a bus likely slammed into the back of a tractor-trailer near Palm Springs, Calif., last October. The incident left 13 people dead and 31 others injured.
The report concluded that undetected sleep apnea and a poor alert system for stopped highway traffic near utility work were to blame for the crash.
The truck driver had been stopped on the highway in traffic due to utility work, but did not resume driving after the traffic stoppage. The NTSB determined that he most likely fell asleep at the wheel “as a result of his undiagnosed moderate-to-severe obstructive sleep apnea.”
The truck driver was also found to have violated hours-of-service rules for several days prior to the crash, while the bus driver was also likely fatigued and had untreated diabetes, according to investigators. Neither vehicle was equipped with crash avoidance technology.
Even though the truck driver was severely obese and considered to be at very high risk for having obstructive sleep apnea, he had not been tested for the condition. Sleep apnea causes a person’s airways to close and stops their breathing during sleep, potentially leading to daytime drowsiness.
The disorder has been linked to a number of deadly transportation incidents, including a fatal New Jersey Transit train crash last year.
The Obama administration had announced plans to require transportation companies to screen their rail, train and bus operators for sleep apnea.
But the Trump administration decided to abandon the screening proposal this summer, saying there was not enough evidence to support rulemaking and pointing out that a number of companies already voluntarily test their employees for sleep apnea.
The NTSB report also blamed the crash on the California Department of Transportation’s inadequate transportation management plan for the traffic break, which resulted in a “hazardous traffic situation.” The bus driver did not receive any advance warning about the stopped traffic ahead.
The board has urged the Federal Motor Carrier Safety Administration (FMCSA) to develop a program that identifies commercial drivers who are at the highest risk for sleep apnea and require those drivers to be appropriately evaluated and effectively treated, if necessary.