Delivery Trucks Can Present a Hazard. Packages or vehicle doors often block the driver’s vision. Drivers of step vans, postal vehicles, and local delivery vehicles often are in a hurry and may suddenly step out of their vehicle or drive their vehicle into the traffic lane. Parked Vehicles Can Be Hazards, especially when people start to get out of them. Or, they may suddenly start up and drive into your way. Watch for movement inside the vehicle or movement of the vehicle itself that shows people are inside. Watch for brake lights or backup lights, exhaust, and other clues that a driver is about to move. Be careful of a stopped bus. Passengers may cross in front of or behind the bus, and they often can't see you.