Compact mixed-use developments are the latest development fad. While such developments promise environmental benefits, the reality is often far different. Two of the largest mixed-use developments in the United States have had limited environmental benefits.
Proponents often cite the fact that mixed-use development residents drive less as an environmental benefit. However, since most car emissions (90-95%) come from cold starts and occur in the first 15 minutes of a trip, the number of miles driven is much less important then the act of driving itself. Reducing the distance driven has a very minimal effect on pollution.
One major redevelopment project is Atlantic Station in Atlanta, GA. Atlantic Station is a new mixed-use development built on an abandoned, polluted steel mill. Cleaning up the steel mill itself, which was a superfund site, clearly had major benefits. But the day-to-day benefits of the mixed-use project are less clear. Despite being located just north of the transit-friendly Midtown area of Atlanta the project was not designed to be transit accessible. All residences come with underground parking and most residents commute to work by car. A bus connecting the development with the MARTA heavy-rail system was discontinued because of lack of use.
Most of the residents of the project moved from other mostly suburban areas of Atlanta but since much of Atlanta’s employment is north of the development, residents may not be driving any less than when they lived in the suburbs. The commute to the Perimeter North Area of Atlanta, which has the largest concentration of jobs in the Southeast U.S., is 13 miles from Atlantic Station. Yet it is only 11 miles from the suburb of Alpharetta, 8 miles from Roswell and 5 miles from Brookhaven. Yet many of these suburban residents who moved to Atlantic Station commute to the Perimeter for employment. And since they cannot reach transit, they commute by car. As a result, no more folks are using transit, and some of the Atlantic Station residents are commuting longer distances than when they lived in the suburbs.
The city of Hayward in the San Francisco Bay area has replaced its affordable housing with a new transit-oriented mixed-use development near its Bay Area Rapid Transit (BART) station. The principle of a transit-oriented development is that most commuters will walk to work or use transit which reduces transportation emissions. However, most of the residences are only affordable to those earning six figure salaries, while most of the employment is in the low-wage service sector. As a result, most of the residents and the workers must commute to their jobs. While approximately 30% use transit, the remaining 70% commute by car. This 30% is still a higher share than the 10% who chose transit when they lived in the suburbs. Perhaps 30% of the retail workers at the development commute by transit, a share not much higher than the San Francisco average.
However, the situation is reversed for the low-income residents. Displaced to the suburbs because their homes were demolished or because their taxes increased so much that they could no longer afford to live in their homes, they now rely on transit which is very limited in the suburbs. When they lived in Hayward, 70% of them rode transit and 30% of them drove. Now displaced throughout the suburbs, only about 10% of them can reach their jobs by transit; 80% now drive and 10% lost their jobs because they could not reach them by transit and could not afford to buy a car. As a result the actual number of people using transit at the Hayward site has actually decreased. More folks are driving, producing more emissions.
There may be lifestyle benefits from building mixed-use developments, but a significant reduction in emissions is not one of those benefits.