While the rollout of autonomous vehicles in Dallas has come with some early traffic issues and concerns remain, a new SMU study found that they could reduce future traffic congestion in the region.
Ride-hailing services with autonomous vehicle technology operating in Dallas began with human-supervised Avride from Uber, which debuted in December, and now also include the driverless Tesla Robotaxi, and Waymo. An Amazon subsidary, Zoox, announced in March that it also plans to serve the area.
High profile instances of autonomous vehicles blocking roadways have garnered headlines and raised concerns, but the new SMU study suggests there may be reason for hope.
The study by SMU civil and environmental professor Khaled Abdelghany and his collaborators utilized a North Texas travel model developed by the North Central Texas Council of Governments, to examine how connected and autonomous vehicles (CAVs) could impact traffic by 2045.
“Traffic congestion is often driven not only by high demand but also by speed variability and stop-and-go behavior, which reduce flow efficiency,” said Abdelghany, a fellow at the Stephanie and Hunter Hunt Institute for Engineering and Humanity. “Autonomous vehicles may help mitigate these effects through smoother and more coordinated driving.”
The study first evaluated how different percentages of fully autonomous vehicles on major roads such as U.S. 75 and Interstate 635 would affect traffic flow. Then, the study evaulated what the added impact of real-time communication between driverless vehicles and traffic signals might be on travel times.
Lastly, the study assessed what the effect might be on DFW traffic if commuters who no longer had to drive lived farther from their workplaces.
Researchers had the model test scenarios with either 25%, 50% or 100% driverless cars over 25 experiments. All experiments were benchmarked against a hypothetical 2045 base scenario that assumes no connected and autonomous vehicles in the traffic composition.
The study, published in the Journal of Urban Technology, found traffic delay fell 33% by 2045 at 100% driverless cars. It also found that daily vehicle-hours traveled (VHT) would decrease by at least 19%, if households and jobs gradually moved from the core parts of Dallas, Tarrant, Collin, and Denton counties to peripheral areas or other cities with full autonomous vehicle adoption. VHT refers to the total amount of time spent by all vehicles traveling within a transportation network or roadway system during a given period.
The study was conducted by Abdelghany, Behruz Paschai, a senior research engineer with the Texas Transportation Institute’s Travel Forecasting Program, and Abby Morgan, an associate engineer at Kittelson & Associates, Inc.
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