Hills or Mountain Roads Beware of dangers caused by slower moving trucks or buses on steep hills, inclines, or mountain roads. Watch for slow moving trucks or buses going both up and downhills. Heavy vehicles cannot maintain speed when climbing hills and must go slowly downhills to stay under control. Watch for trucks or buses that might be in trouble. Smoking wheels or a high speed can be a sign of brake loss. If you encounter this situation, fallback and DO NOT pass. Runaway Truck RampsThese ramps are designed to stop out-of-control trucks or buses going down step downgrades. Vehicles should never stop or park in these areas.