Public transit is often viewed by planners and transportation officials as a key strategy for reducing car dependency, easing traffic congestion, and lowering emissions. Every person who opts for transit over driving helps reduce the total miles driven in private vehicles. According to a large national study, however, good transit has a ripple effect on land use and travel behavior. For every mile not driven by transit riders, transit accounts for another six to nine miles not driven among the larger population.
VMT
Moving from LOS to VMT is more complicated than it might seem
Traffic engineers across the U.S. are accustomed to measuring road performance in terms of “level of service,” or LOS. Recognizing its unintended consequences, many transportation professionals and advocates have urged the industry to replace it with something better. However, LOS has become so ingrained in many processes that there is probably no single alternative to its use.
Telecommuting most likely increases travel
We’ve written before about the impact of telecommuting on travel demand. Contrary to some common assumptions, it often results in longer non-work trips or broader changes in travel behavior. As transportation agencies consider telecommuting as a viable strategy to cut travel—especially since the pandemic—a new comprehensive review presents mixed results.
Workers offset their commute travel when working from home
The massive shift to remote work during the pandemic altered the way many offices operate and increased interest in the potential for widespread telecommuting to help reduce traffic, transportation emissions, and other harmful impacts. We have reported several studies, however, that suggest remote work simply lets people drive at different times of day and for purposes other than commuting. A new study backs that finding.
To manage traffic, researchers ask: “Whose miles are these anyway?”
Several states and many local governments are growing more interested in measuring vehicle miles traveled (VMT) as a key indicator of transportation emissions levels and other unwanted impacts. But measuring VMT, especially at the local site level, can be more difficult than it seems. A new study in the Journal of the Planning Association points to data sources, shortcomings, and considerations for measuring VMT in the future.
State DOTs are key players in cutting transportation emissions
Through a combination of carrots and sticks—but mostly carrots—the federal government has encouraged state DOTs to take ambitious steps to lower the environmental impacts of transportation and to invest in more sustainable travel options. Two years into the Bipartisan Infrastructure Law (BIL), notes Adie Tomer at Brookings, it is still hard to know the impacts. Many states are still operating under the status quo. Others, however, including many SSTI partners, are seizing the opportunity to bolster ongoing local sustainability initiatives.
Success driving less
Driving less is one of the keys to reducing greenhouse gas emissions from the transportation sector, and to reducing the number of deaths and serious injuries on our roads. Most states have seen an increase in per capita vehicle miles traveled over the last 25 years. There are exceptions, however, where political action, multimodal investment, or the development of compact neighborhoods acted to pull VMT numbers down, says a new report by the Frontier Group.
Not having to drive would reduce VMT
In one sense, departments of transportation are in the business of making it possible for people to travel less, or to at least spend less time traveling. But choosing to build capacity and reduce delay effectively speeds up drivers rather than shortening the length of their trips—in an era when driving less is acknowledged as a first-order climate change mitigation strategy. A recent article in Planetizen proposes a solution. If efforts were focused more on allowing people to conduct their daily affairs—shopping, banking, working, health care—over the internet or on the phone, the author writes, it might make a dent in vehicle miles traveled (VMT): a reduction that decades of tepid investment in multimodal options have not been able to achieve.
When driving gets tough, the tough adapt
Conventional thinking holds that congestion stifles the economy. Sitting in traffic or having it take longer to get someplace important would seem to be a drain on productivity. On the contrary, a group of Texas researchers looking at travel survey data from the Puget Sound area of Washington State found that travelers exposed to traffic congestion and travel delay will simply find a means of getting from point A to point B that doesn’t rely on driving. Their novel approach incorporates data on whether people choose to live in places that support their preferred travel options or way of life, addressing the question of residential self-selection.
Americans are still driving less than before the pandemic
Vehicle miles traveled (VMT) in the U.S. totaled 3.17 trillion last year, according to preliminary estimates from FHWA. That is a one percent increase from 2021 and a nine percent increase from 2020—the height of the pandemic—but still nearly three percent lower than VMT in 2019. After accounting for population growth, the average American drove four percent less in 2022 than in 2019 and six percent less than the highest point in 2004.