A “CBS This Morning” investigation reveals drivers can hide medical conditions that should keep them off the road.

But just a few weeks before the crash, a Department of Transportation medical examiner suspected Garrett might have sleep apnea – a breathing condition that disrupts sleep and leads to fatigue. If untreated, it disqualifies a driver from operating a commercial vehicle like a bus. Garrett got a 90-day waiver and was told to get tested.

“What did the DOT doctor say? He claimed that I had one of the markers for sleep apnea, which was he could not see the back of my throat,” Garrett said.