Alley - United States

United States

In the United States alleys exist in both older commercial and residential areas, for both service purposes and automobile access. In residential areas, primarily those built before 1950, alleys provide rear access to property where a garage was located, or where waste could be collected by service vehicles. A benefit of this was the location of these activities to the rear, less public side of a dwelling. Such alleys are typically roughly paved, but some may be dirt. By 1950 they had largely disappeared from development plans for new homes.

Chicago, Illinois has about 1,900 miles (3,100 km) of alleyways. In 2007, the Chicago Department of Transportation started converting conventional alleys which were made out of asphalt, into so called Green Alleys. This program, called the Green Alley Program, is supposed to enable easier water runoff, as the alleyways in Chicago are not connected to the sewer system. With this program, the water will be able to seep through semipermeable concrete or asphalt in which a colony of fungi and bacteria will establish itself. The bacteria will help breakup oils before the water is absorbed into the ground. The lighter color of the pavement will also reflect more light, making the area next to the alley cooler.

Manhattan, New York City is unusual in that it has very few alleys.