"American parking structures are as varied and unique as the destinations they serve and the density of the area in which they are located. Their form and architecture reflect their users. For example, distinct differences exist between parking garages that serve suburban office workers, or retail shoppers, and visitors to the downtown urban core. The size and design of these structures is also affected by factors including the location, whether the structure qualifies as a shared parking, cost and availability of different building materials, and the available parking technology..."