provide better maneuverability in tight situations. They are also among the most severe-duty and highest GVWR trucks on public roads. Semi-tractors ("artics" in the UK) have a fifth wheel for towing a semi-trailer instead of a body. Tank trucks ("tankers" in the UK) are designed to carry liquids or gases. They usually have a cylindrical tank lying horizontally on the chassis. Many variants exist due to the wide variety of liquids and gases that can be transported. Wreckers ("recovery lorries" in the UK) are used to recover and/or tow disabled vehicles. They are normally equipped with a boom with a cable; wheel/chassis lifts are becoming common on newer trucks. Sales and sales issues Manufacturers Truck market worldwide Driving In many countries, driving a truck requires a special driving license. The requirements and limitations vary with each different jurisdiction. Australia In Australia, a truck driver's license is required for any motor vehicle with a Gross Vehicle Mass (GVM) exceeding . The motor vehicles classes are further expanded as: Combination HC: Heavy Combination, a typical prime mover plus semi-trailer combination. MC: Multi Combination, e.g., B Doubles/road trains Rigid LR: Light rigid: a rigid vehicle with a GVM of more than but not more than . Any towed trailer must not weigh more than GVM. MR: Medium rigid: a rigid vehicle with 2 axles and a GVM of more than . Any towed trailer must not weigh more than GVM. Also includes vehicles in class LR. HR: Heavy Rigid: a rigid vehicle with three or more axles and a GVM of more than . Any towed trailer must not weigh more than GVM. Also includes articulated buses and vehicles in class MR. Heavy vehicle transmission There is also a heavy vehicle transmission condition for a license class HC, HR, or MC test passed in a vehicle fitted with an automatic or synchromesh transmission; a driver's license will be restricted to vehicles of that class fitted with a synchromesh or automatic transmission. To have the condition removed, a person needs to pass a practical driving test in a vehicle with non-synchromesh transmission (constant mesh or crash box). Europe Driving licensing has been harmonized throughout the European Union and the EEA (and practically all European non-member states), so that common rules apply within Europe (see European driving licence). As an overview, to drive a vehicle weighing more than for commercial purposes requires a specialist license