Household-based travel measures may help agencies cut emissions

Reprinted from Catalyst, December 15, 2025

Across the country, transportation agencies, including the Minnesota Department of Transportation (MnDOT), are working to meet ambitious targets for reducing vehicle miles traveled (VMT) and climate emissions. To succeed, they need to understand what actually encourages households to drive less.

A recent University of Minnesota (UMN) research study aimed to answer this question. Led by Eric Lind, director of the UMN’s Accessibility Observatory, the study examined how accessibility—the opportunities reachable by different travel modes such as driving, public transit, or biking—influences a household’s VMT.

“We wanted to go beyond the typical approach of using roadway volume counts and instead examine households, because that is where VMT comes from,” Lind says. “This helps us better understand the influence of transportation and land-use systems on the travel decisions people make in their daily lives.”

Lind and his research team used Twin Cities travel behavior survey records to match households with access to opportunities on three different levels: local access (biking to jobs within 20 minutes), transit access (walking or rolling to transit to reach jobs within 10 to 40 minutes), and regional access (driving to jobs within 20 to 60 minutes). The models also accounted for important demographic factors including household income, vehicle availability, and number of workers.

The findings point to a challenging road ahead for transportation agencies working to reduce VMT and greenhouse gas emissions. The good news is that higher local and transit access does lead to lower expected VMT. However, the impact is modest: doubling local or transit access to jobs results in a VMT decrease of about 3 percent.

Conversely, higher regional auto access is the most influential factor and positively predicts higher VMT. According to the model, a modest 10 percent increase in regional auto access to jobs resulted in a VMT increase of roughly 4 percent.

“The challenge is that MnDOT is required to balance increasing roadway capacity with strategies that reduce VMT to the same extent,” Lind explains. “Increasing what is easily reachable by bike or transit does lead people to drive less, but these are nudges compared with the main effects of roadway expansions that have a much larger, counteracting effect on VMT.”

To meet VMT goals, the research team recommends a two-pronged approach. First, agencies must continue to invest in and increase local and transit and nonmotorized access. Second, they must critically assess any planning that increases regional auto access, as its VMT-boosting impact requires non-auto mitigation to balance it out.

These findings will provide MnDOT and other transportation agencies with a clearer understanding of the levers available to them, offering the estimates needed to calculate the true VMT impact of future infrastructure changes.

This study was sponsored by the Applied Research in Transportation (ART) Program, which addresses time-sensitive research questions in a 6- to 12-month timeframe. CTS and MnDOT contributed initial funding to launch this pilot program in 2024, with the Metropolitan Council joining in 2025. To reinforce the applied nature of the program, ART projects must directly address a current process, document, or policy need with an initial focus on sustainability in transportation and climate change impacts.