Many communities allocate more space to parking than they really need, often due to excessive parking requirements. Parking facilities have a range of adverse impacts on human health and the natural environment. Too much parking leads to people driving more than they would otherwise, contributing to a more car-dependent, sedentary lifestyle and increasing air pollution and greenhouse gas emissions. Parking lots also create impervious surfaces that worsen potential flooding conditions and carry car oil and other toxins into waterways during rain events. Existing parking lots are prime targets for green infrastructure and other stormwater management standards and projects. In commercial developments, surface parking lots often consume large tracts of natural and agricultural lands, though they are rarely, if ever, filled to capacity.

Too much parking creates dead space in urban areas that could otherwise be occupied by housing, parks or other public amenities, and ultimately reduces walkability. The most important way to manage parking demand is to expand alternatives to driving alone, such as transit, biking and walking. Surface parking lots also present opportunities for sustainable redevelopment projects, like transit-oriented development, parks, community spaces and green infrastructure.