Results

The five projects analyzed using URBEMIS all show significant traffic reductions over an average housing development in the region (see table 6 for summary).

On average, a household in our region drives 45 miles daily. All five of the projects show significant reductions in estimated daily miles driven per household compared to the regional average.

The building with 100% affordable housing showed the greatest projected VMT reduction. Households there would average an estimated 17 miles per day and 16 pounds of CO2 per day, meaning 63% less driving and 77% fewer pounds of C02 emissions than the regional average.

The other four projects generated similar results despite variation in location, parking supply, and transit service. These four projects, which each had no more than 10% affordable housing, are projected to generate daily VMT of 20-25 miles and CO2 emissions of 20-25 pounds per household per day. These projects significantly outperform the average household, cutting vehicle miles driven and CO2 emissions roughly by half.

These results, however, are conservative and likely don’t fully capture the reductions in VMT and emissions. That’s because URBEMIS builds off the conventional ITE trip generation model, which includes assumptions of high VMT generation.

URBEMIS is likely overestimating the daily miles traveled for households living in the buildings with no parking, high levels of transit service, and nearby access to jobs, stores, and other amenities.

Our results reinforce the widely acknowledged need to develop alternative analytical tools that can better account for vehicle trip reduction in a highly walkable, transit-served neighborhood.