Double parking can refer to one of three practices:
"Double parking" can refer to the usually illegal practice of parking a vehicle to the side of a row of vehicles that is already parked next to the curb. This often prevents some of the vehicles in the first row from departing and always obstructs a traffic lane or bike lane (to the extent of often making the street impassable in one-way single-lane situations). Even though it is illegal, double parking is quite common in large urban areas. In some areas, people double parking their cars leave the hand brake off, allowing the drivers of the cars next to the curb to push the double parked car a little forward or backward, in order to allow departing from the parking spot. Double parking in this fashion, where illegal, is often punished by ticketing or towing the offending vehicle.
Attended lots and garages frequently use double parking to maximize vehicle storage density. A driver who double-parks in an attended lot leaves the vehicle's keys with the attendant. If the driver of the blocked car returns first, then the attendant can move the blocking car so that the blocked car can leave. This practice is especially common for valet lots, in which attendants have the keys to all vehicles.
The term "double parking" is sometimes used to describe parking over the lines separating two designated parking spaces in a parking lot and is derived from situations where cars take more spaces than necessary. Though this practice is most commonly a result of the driver disregarding the separating lines, it may also occur when the driver avoids parking too close to a large vehicle (such as a truck or SUV) in a narrow space, or to a vehicle which is poorly centered in the adjacent space. Sometimes parking in this fashion, if the vehicle is large, is an attempt by the driver of the vehicle to avoid damage to the vehicle or to nearby vehicles when the doors are opened, or to ensure enough space for loading and unloading various content. The egregiousness of double parking in this fashion is usually judged depending on parking space availability. If a lot is mostly empty, parking in such fashion will most likely provoke only a chuckle from the passers-by, but it can provoke anger and even vandalism towards the offending vehicle when parking is scarce.