Driving ambition

• UC Irvine's new Brain, Body & Behavior Driving Simulation Lab examines novice driver behavior and decision-making to aid understanding of motor vehicle crash risk.
• In addition, an NIH-funded study is exploring whether lower blood alcohol limits for 21- to 24-year-olds could reduce DUI-related accidents and deaths.

Motor vehicle crashes remain one of the leading causes of death among teenagers. For the youngest drivers, getting behind the wheel marks freedom but also comes with measurable risk. At the University of California, Irvine, Dr. Federico Vaca, professor and executive vice chair of emergency medicine, is determined to change that trajectory.

"Driving licensure among our youngest drivers remains a major life milestone, and it allows for newfound freedom and opportunity for not only youth but their parents as well. At the same time, learning to drive and licensure come at a time when youth are rapidly moving through life with new transitions in school, with friends, and likely exposure to alcohol and drugs," he says. "Our priority … is to examine the complexities of young driver behavior and to thoroughly understand crash injury risk and crash prevention among this special group of drivers."

Vaca's work is at the intersection of health, transportation science and policy. A fellow of the Association for the Advancement of Automotive Medicine and a researcher at UC Irvine's Institute of Transportation Studies, he previously served as a medical fellow at the U.S. Department of Transportation's National Highway Traffic Safety Administration in Washington, D.C. His long-standing goal is to prevent the injuries he has seen and treated in emergency departments and trauma centers through rigorous research, using the findings to inform and advance evidence-based programs and policies that save lives on the road.

Innovating safety science

UC Irvine is home to a new hub for understanding and preventing crash injuries among young drivers, the Brain, Body & Behavior Driving Simulation Lab, founded by Vaca and his interdisciplinary team.

At the heart of the B³DrivSim Lab is a high-fidelity, half-cab driving simulator capable of replicating real-world conditions with precision. It uses advanced software to design customized driving scenarios - from complex roadway environments to the inclusion of such human elements as distraction and fatigue - all while capturing real-time video and driving behavior as well as vehicle control metrics.

This integration of medicine, behavioral science and engineering enables researchers to measure how developmental and socioecological factors shape driver decisions in unique and consequential ways.

The B³DrivSim Lab also represents a growing mentorship ecosystem at UC Irvine. In mid-June, the facility welcomed Siwei Hu, a postdoctoral scholar who earned a Ph.D. in civil and environmental engineering, with a focus on transportation studies, at UC Irvine. Hu works closely with Vaca to combine engineering and modeling analytics with behavioral and crash risk insights.

The half-cab driving simulator uses advanced software to replicate real-world conditions and design customized driving scenarios - from complex roadway environments to the inclusion of such human elements as distraction and fatigue - all while capturing real-time video and driving behavior as well as vehicle control metrics. Steve Zylius / UC Irvine

From the lab to policy

Beyond simulation, Vaca's latest National Institutes of Health-funded study, separate from his lab's work, takes this philosophy to the national level. His project, "Modeling a National Graduated-BAC Policy for 21- to 24-Year-Old Drivers," explores whether lowering the legal blood alcohol limit for young adults could reduce alcohol-related crashes and deaths.

"When you turn 21, at that very moment, the application of several alcohol-related prevention laws changes in the blink of an eye," Vaca says. "Before that, the minimum legal drinking age and zero-tolerance laws are in place to protect young drivers from alcohol-impaired driving. Effectively, the second you turn 21, those prevention policies don't apply, and you're suddenly allowed to have a much higher blood alcohol concentration in your body that's intimately tied to serious and fatal crash risk. It's a very dangerous disconnect."

The study will use national crash data, behavioral surveys and system dynamics modeling to examine how a "graduated BAC policy" might bridge that gap, giving young adult drivers a safer transition into full legal responsibility and saving many more lives.

Bridging science, education and prevention

Earlier this year, Vaca and his B³DrivSim team joined prevention program educators, policymakers, engineers and law enforcement professionals in Anaheim at a Ford Driving Skills for Life event, part of a Ford Philanthropy-sponsored national effort teaching teens hands-on safe driving techniques - from hazard recognition to impaired-driving awareness. Speaking to more than 130 high school students and their parents from local and distant communities, Vaca emphasized the connection among driving, independence, opportunity and responsibility.

That message aligns with his broader initiative, Youth Thriving in Life Transitions with Transportation, which introduces high school students to traffic safety and transportation science and their role in promoting health, education and employment in early adulthood. By linking research and real-world experience, the project empowers youth to see mobility as a foundation for opportunity with safety as its cornerstone.

With overall young driver crash fatalities rising 25 percent nationally over the last decade and a 46 percent increase in fatal crashes where a young driver had a BAC of ≥ .01/dL, Vaca's work represents a crucial step toward reversing that trend.

Through a combination of clinical insight and prevention, transportation and data science underscored by community collaboration, he and his team are redefining how researchers and policymakers think about youth driver safety.