Are the vehicles parked on level ground with their parking brakes on and the ignition key removed?
Vehicles should be parked on firm and level ground, preferably in a parking area. A piece of ground may look flat, but it only needs a slight gradient for a vehicle to move if the parking brakes are not applied. A vehicle should not be left unless the parking brakes have been firmly applied, the engine has stopped, the starter key has been removed, and any mounted equipment has been lowered to the ground or secured. It is important to lock away the keys of vehicles left parked in workplaces overnight, at weekends or when they are being left for long periods.
