Workers prepare to haul away a tour bus that crashed into a semitrailer in October 2016 on Interstate 10 near Palm Springs, Calif. Officials believe the accident, which killed 13 people, involved the drivers of both vehicles falling asleep behind the wheel.

Workers prepare to haul away a tour bus that crashed into a semitrailer in October 2016 on Interstate 10 near Palm Springs, Calif. Officials believe the accident, which killed 13 people, involved the drivers of both vehicles falling asleep behind the wheel.