The National Transportation Safety Board has begun an investigation into the July 12 crash of a Greyhound bus into three tractor-trailers parked along the exit ramp of the Silver Lake Rest Area on westbound Interstate 70 near Highland, Illinois.
Three bus passengers died and numerous others were injured in the collision, which occurred at about 2 a.m.
NTSB Member Tom Chapman conducted a media briefing on the agency's safety investigation, which he said is being conducted parallel to the one undertaken by the Illinois State Police. He said the NTSB is "particularly interested" in rest area safety, bus occupant protection, and potential driver fatigue and medical fitness.
Chapman said the investigative team would be on the scene for from four to six days. He said a final report would be available within 12 to 24 months.
