Vehicular elevators are used within buildings with limited space (in lieu of ramps) to move cars into the parking garage. Geared hydraulic chains (not unlike bicycle chains) generate lift for the platform and there are no counterweights. To accommodate building designs and improve accessibility, the platform may rotate so that the driver only has to drive forward. Most vehicle elevators have a weight capacity of 2 tons, while some are large enough for 20-ton commercial vehicles.