Transportation planning and implementation play important roles in the placement of affordable housing. New roads and highways, rather than comprehensive long-range plans, frequently determine the growth and direction of cities and towns, and affect the location of low-income homes and the people who live in them.

New loop roads or highways, for example, often spark the creation of new development in the form of shopping centers, office parks, and housing developments, as well as families of feeder roads leading into the highway. Roads and developments are often built on what was once rural land, driving up the cost of land in the area and potentially displacing long-time residents.

The new roads and developments tend to be located on the fringes of towns, creating a more sprawling city and drawing businesses from the center of towns. Jobs, services and stores become spread across a wider area, with limited transportation options. The new neighborhoods, if they do include affordable housing, are often not included in a city's public transportation plan, and sidewalks tend to be rare. Reliance on the automobile is increased, making car ownership mandatory and driving up transportation costs for everyone.

Downtowns, including what are often low-income neighborhoods, tend to suffer from poor road-building choices. Affordable housing and poverty become concentrated primarily in central cities, while businesses leave, leading over time to bad schools, higher crime rates, and unreliable neighborhood services.

An effective transportation system means more than just less traffic. It should also serve the city's residents by decreasing the concentration of low-income neighborhoods and slowing the outward movement of low-wage jobs and vital services such as healthcare and childcare. When housing is near good jobs, strong schools and well-funded services, children fare better and have more opportunities to achieve stability.

Smart and effective transportation planning can focus investment on areas of a city that need it the most and can help revitalize a community. In addition, good transportation planning can empower local communities by bringing citizens into the planning process as active partners with businesses and government. As a result, communities that often feel excluded from decision-making become more involved in the process, and all parties have a stake in determining the future vision for the community.