Commuting by car, regardless of whether the vehicle is electric or gas-powered, continues to pose health risks due to prolonged sedentary behavior, according to Lawrence Frank, professor of urban studies and planning at UC San Diego. Frank revisited his influential 2004 study in a new commentary published in the American Journal of Preventive Medicine, emphasizing that technological advances such as electric vehicles have not addressed the root issue of inactivity.
“You can spend just as much time sitting in an electric vehicle as you can in a gas one,” said Frank. “Every hour in a car will still be a 6% increase in the likelihood of obesity.”
Frank’s original research was part of the Strategies for Metropolitan Atlanta’s Transportation and Air Quality (SMARTRAQ) project. It established a link between neighborhood design, time spent driving, and increased risk of obesity. This work contributed to tools like Walk Score and has influenced urban planners across North America.
His recent commentary, co-authored with Jacob Carson from the UC San Diego Herbert Wertheim School of Public Health and Human Longevity Science-San Diego State University Joint Doctoral Program in Public Health, reviews two decades of evidence on how city layouts and daily habits impact not only obesity but also conditions such as heart disease, diabetes, and mental health.
Frank stated that walkable neighborhoods with accessible public transit deliver significant health benefits, particularly for those most at risk. However, he noted that transportation budgets rarely account for these health costs: “We are still driving blind,” he said. “We’re acting like these things don’t exist, but they’re so huge.”
Carson added: “The last 20 years of technological progress haven’t changed the original findings of this paper, and neither will the electrification or autonomization of cars. Robust public transportation and safe cycling and walking infrastructure are still relevant solutions to the challenge of creating healthy and sustainable communities.”
To help cities make informed decisions about investments in infrastructure such as streets, sidewalks, and transit systems, Frank’s team has developed tools like the National Public Health Assessment Model. These tools allow municipalities to use cost-benefit analyses similar to those applied for congestion or emissions when considering public health impacts.
“Most people do not find the time to be physically active to counter the adverse effects of sedentary driving time,” Frank said. “You have to reduce car dependence — and integrate active transportation into daily life.”
In related research published in Cities, Frank found that small-scale features—such as sidewalks, trees, benches, shade structures, and safe street crossings—can significantly improve public health outcomes by encouraging physical activity among residents. He emphasized that these improvements are relatively easy and inexpensive to implement.
“Investing in those small features,” he said, “is fairly easy to do, it’s fairly inexpensive. That’s going to give you the biggest return on investment of anything you can do to improve public health through transportation investment.”
Frank also highlighted that low-income neighborhoods stand to benefit most from investments aimed at promoting active transportation: “Focus the investment on active transportation and pedestrian features,” he said, “in the places where people are most likely to develop chronic disease.”
He concluded that practical changes—like adding shade or benches—can encourage more people to leave their homes for outdoor activities without waiting for major policy shifts or funding bills: “We’ve learned exactly how the built environment shapes behavior,” he said. “Now it’s time to put that knowledge to work — because every mile we walk instead of driving matters.”
