As autonomous vehicles (AVs) near widespread use, researchers at The University of Texas at Arlington say the technology could change not just how people travel but how much, reshaping traffic congestion, city planning and public policy.
In a recent study, UT Arlington civil engineering professors Stephen Mattingly and Farah Naz examined how AVs may influence travel behavior, particularly changes in vehicle miles traveled, or VMT—a key measure of total roadway use. They found that widespread adoption of AVs could increase traffic congestion.
Dr. Naz said it is important to understand the impact of AVs before they become part of everyday life.
"We were motivated by the idea that autonomous vehicles could reshape travel in ways that go far beyond simply replacing the driver," Naz said. "Because we are still in a period when policy can be shaped before large-scale adoption occurs, we saw an opportunity to study these potential effects early."
Dr. Mattingly echoed that urgency, emphasizing the importance of proactive planning.
"We are at a moment in time where policies may still be enacted before market factors alone take hold and create situations the current transportation system may not be able to adapt to," he said. "We hope policies may be created proactively before the problems overwhelm the system."
Already, major Texas cities like Dallas, Austin, Houston and San Antonio have allowed deployment of such vehicles in an effort to test their viability. Most are operating in and around downtown areas, a pattern researchers say could expand as adoption increases.
The researchers found that AV adoption is likely to increase traffic congestion and travel time as more vehicles are added to the roads and highways.
"In our meta-analysis, the combined results showed an average 5.95% increase in vehicle miles traveled," Naz said. "Shared AVs were associated with about a 5.3% increase, while non-shared AVs showed a larger increase of about 6.9%."
She added that these increases reflect not only changes in human travel behavior, but also changes in how vehicles operate independently.
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Mattingly said VMT remains one of the most important ways to understand these impacts at a system level.
"VMT measures total system usage," Mattingly said. "Increases in VMT during typical travel periods will provide a sense of overall growth in demand and expected congestion."
For commuters, AV adoption could bring both convenience and new challenges.
"The rise of AVs could make commuting more convenient, but it may also lead to more pick-up and drop-off activity, more empty vehicle trips, and new costs," Naz said. "Cities will need to prepare for increased pressure on curb space and changes in parking demand."
Mattingly added that in an automated future where people still own their own vehicles, new questions will emerge about how vehicles are used when not occupied.
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"Where will commuters send their car when they don't need it?" Mattingly said. "Will it be sent to a parking lot, sent to try to find other riders or sent home? These decisions could create new pressures on the transportation network."
Beyond individual travel, AVs could gradually reshape cities and regional growth.
"Easier travel could encourage people to live farther from where they work," Naz said. "That could reshape congestion patterns, land use and the overall experience of daily travel."
Mattingly noted that while reduced parking demand may open redevelopment opportunities, those changes will take time. For regions like North Texas, where congestion is already a major concern, the implications are especially significant. Without policy intervention, such impacts could worsen.
"Greater VMT will likely intensify existing congestion problems in an area like DFW if policy or incentives do not shift some travel to other times of the day," he said.
Naz said policymakers should focus on integrating AVs into the broader transportation system in a way that supports—not replaces—more efficient modes.
"AVs should not be priced or regulated in ways that pull riders away from public transit, walking or biking," Naz said. "Instead, policies should encourage AVs to play a complementary role."
She also encouraged consumers to think carefully about how AV adoption may affect their long-term travel habits and costs.
While AVs offer potential benefits, both researchers emphasized that uncertainty remains.
"AVs are not inherently good or bad," Naz said. "Their impacts will depend heavily on how they are deployed and governed."
Looking ahead, both researchers said successful implementation will depend on safety, infrastructure and collaboration.
"AVs must clearly demonstrate that they are safer and more reliable than human-driven vehicles," Naz said. "But safety must also include better street design and protections for people who walk and bike."
Mattingly added that addressing these challenges will require coordination across sectors.
"These solutions will require collaborations between commuters, public agencies and private companies," he said.
About The University of Texas at Arlington (UTA)
The University of Texas at Arlington is a growing public research university in the heart of Dallas-Fort Worth. With a student body of over 42,700, UTA is the second-largest institution in the University of Texas System, offering more than 180 undergraduate and graduate degree programs. Recognized as a Carnegie R-1 university, UTA stands among the nation's top 5% of institutions for research activity. UTA and its 280,000 alumni generate an annual economic impact of $28.8 billion for the state. The University has received the Innovation and Economic Prosperity designation from the Association of Public and Land Grant Universities and has earned recognition for its focus on student access and success, considered key drivers to economic growth and social progress for North Texas and beyond.
