A train has just passed and the tracks appear clear. What must a bus driver do before proceeding across a railroad crossing?

49 CFR 383.117(a)(4), Proper procedures at railroad-highway grade crossings and drawbridges

Multi-track crossings are especially dangerous because a second train can arrive on another track right after the first one passes, hidden by the first train's noise and bulk. Checking again, and never getting stuck mid-crossing by shifting gears, keeps a stalled bus off the tracks when a train is coming.