The size of a parking lot varies wildly based on zoning laws, but a standard American parking space is usually 9×18 feet. For a medium-sized retail store, a parking lot might hold 100 to 200 cars, taking up about 1 to 2 acres of land. Large shopping malls or stadiums can have lots that span 50 to 100 acres or more. Architects use a "rule of thumb" that accounts for not just the spaces, but the "drive aisles" (the lanes between rows), which usually need to be about 24 feet wide for two-way traffic. When you factor in landscaping, runoff drains, and handicapped stalls, a parking lot often ends up being larger than the actual building it serves. In many US cities, "minimum parking requirements" have historically forced developers to build lots that are much larger than necessary, leading to the vast asphalt landscapes we see today.