 The expanding distance between gainful employment and housing made affordable by the income it provides has caused people to seek housing on the periphery of settled areas.This is cited as a contributor to urban sprawl, typified by traffic congestion, lengthy commutes, convenience stores and strip retail centers, and the rapid consumption of open space due to the building of new homes taking place at the outer edges of metropolitan areas where land is typically cheaper.While prevalent in US metropolitan areas, workforce housing issues may arise anywhere that land values or other restrictions on creation or availability of quality affordable housing units are constrained by zoning, market forces or physical boundaries.