Transit-oriented development reduces emissions

Housing near transit, retail

Jon Boyd, Jul 16, 10.

People living in neighborhoods with mixed-use development and access to high-quality transit can reduce mobile source greenhouse gas (GHG) emissions by 43 percent, according to a study released in June by the Center for Neighborhood Technology (CNT) and the Center for Transit-Oriented Development (CTOD). The study found that people living downtown reduced mobile source GHG by 78 percent. The study area contrasted different neighborhood types within the Greater Chicago region, and associated different neighborhood types with a GHG emmision coefficient based on CNT’s Housing Cost + Transportation Cost research. Houston Tomorrow reported on Housing + Transportation Cost in March 2010.

“This research shows that, in a nutshell, location does indeed matter,” said Scott Bernstein, President of CNT. “Individuals and families that live near transit centers own fewer automobiles, drive fewer miles, and leave a much smaller carbon footprint than those who don’t.”

The study calculates mobile source GHG emissions from households, and measures the differences based on current housing patterns. However, they also examine different strategies to achieve higher reductions in mobile source GHG emissions:

The study shows that for every household, the number of cars owned and the number of miles driven is largely determined by where that household lives. Take, for instance, a worker who lives in a suburb with no access to transit. His or her household will have an average carbon output related to vehicle miles travelled of 7.15 tons of CO2 per year. If however, he or she decides to move into the city, near a transit system in a walkable neighborhood with access to jobs and amenities, this household’s average VMT-related carbon output drops to 4.07 tons. That is a 43 percent reduction from levels of emissions that would have taken place without those strategies.

This study also examines real-world potential to use transit and transit-oriented development as an emissions reduction strategy in three different future development scenarios for the Chicago
metropolitan area. The first is business-as-usual. The second assumes that residential and employment growth will continue at the same rate in the city and in the suburbs, but that all of this growth will be accommodated in the half-mile radius around stations. The second scenario is based on growth projections from Chicago’s regional planning agency. The third scenario explores concentrating housing and jobs within a half-mile radius of transit stations, regardless of growth projections. The second scenario reduces emissions by 28 percent from levels of emissions growth that would have taken place without those strategies, while the third scenario results in a 36 percent reduction from levels of emissions growth that would have taken place without those strategies. (The study assumes no additional investment in transportation and the same number of car owners). In short, transit-oriented development offers a way to build the future that provides for sustainability and affordability.

According to the study, of the 28 percent of GHG that are transportation-related, 61 percent are related to household automobiles. Ths study is examining TOD strategies which could result in a 17 percent reduction in regional GHG emissions.

(Photo credit: LHOON)

Comments

Paul M. Suckow said:

Absolutely, if all new development were TOD sandwiched within a half mile of a bus/rail center, then Houston would shortly have the finest public transit services available anywhere. Better make that radius 1/4 mile to begin considering the summer heat and pounding rains we are likely to endure here. Yet, given appropriate density around transit centers, these could grow to be surrounded by a wall of beautiful structures, and enjoy cooled air at lower level within the center boundary, similar to the way the cooled lower air layer of a large indoor industrial space can be efficiently maintained today. With high albedo toward the sky and plenty of shaded plantings and water features throughout the first two levels above the natural ground, an all-pedestrian center could become a magastructure in itself.

Urban agriculture could occupy the vertical walls that received reflected sunlight, while rainwater could be captured from the top-sails that created both wind and solar energy while shading and reflecting natural light into the open and built spaces below. The natural ground, while crisscrossed by efficient transit lines, utility lines and water courses along artificially designed ridges and beautifully landscaped much as Hawaii is today, a man-made garden of Eden, would function very naturally as a floodplain. Small lakes and permanent wetlands would occupy the flood-settling basins that scalloped in between. Well above the surface, clear of and resistant to the 30 foot storm surges that at some point became possible, the built environment with planted terraces and open spaces would merge daily life and nature in a myriad of pathways in three dimensions.

All component structures were designed to allow abandonment of two lower floors at a time, raising the whole structure by two new stories as the entire infrastructure was rebuilt and refreshed. Thus the sea steadfastly rose to undergird this entire megastructure and its vital connections to so many others that were entwined all the way back to the beach on its march toward the Texas Hill Country. In time, Houston became a dense network of megastructures housing 20 million international people, an atomic arrangement of brilliant white arrayed in an expanded vibrant blue Gulf. To and fro sailing ships and airships of every description ventured to visit this unique site from the hundred or so other megacities of our next next century.

Posted on Jul 20, 10 at 9:11 pm

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