job is in progress, although this is not possible on units which require secure outriggers, and therefore most common on the scissor lift types. The power can be almost any form of standard mechanical drive system, including electric or gasoline powered, or in some cases, a hybrid (especially where it may be used both inside and outside). Such person lifts are distinguished from telescopic handlers in that the latter are true cranes designed to deliver cargo loads such as pallets full of construction materials (rather than just a person with some tools). Vehicle-mounted Some units are mounted on a vehicle, usually a truck. They can also be mounted on a flat-back pick-up van known as a self drive, though other vehicles are possible, such as flatcars. This vehicle provides mobility, and may also help stabilize the unit – though outrigger stabilizers are still typical, especially as vehicle-mounted AWPs are amongst the largest of their kind. The vehicle may also increase functionality by serving as a mobile workshop or store. Control The power assisted drive (if fitted) and lift functions of an AWP are controlled by an operator, who can be situated either on the work platform itself, or at a control panel at the base of the unit. Some models are fitted with a panel at both locations or with a remote control, giving operator a choice of position. A control panel at the base can also function as a safety feature if for any reason the operator is at height and becomes unable to operate his controls. Even models not fitted with a control panel at the base are usually fitted with an emergency switch of some sort, which allows manual lowering of the lift (usually by the release of hydraulic or pneumatic pressure) in the event of an emergency or power failure. Controls vary by model, but are frequently either buttons or a joystick. The type and complexity of these will depend on the functions the platform is able to perform, such as: Vertical movement Lateral movement Rotational movement (cardinal direction) Platform / basket movement — normally, the system automatically levels the platform, regardless of boom position, but some allow overrides, tilting up to 90° for work in difficult locations. Ground movement (in self-propelled models) Safety The majority of manufacturers and operators have strict safety criteria for the operation of AWPs. In some countries, a licence and insurance