Iowa researchers are studying how to make roads and traffic safer for all ages.

Whether we’re crossing a street as a pedestrian, riding a bike, or driving a vehicle, navigating traffic can be complex. Researchers in the College of Public Health are studying different aspects of road safety and how to prevent injuries throughout the lifespan, including two recent studies that examine road crossing in childhood and driving in older adulthood.

Parent-Child Interactions in Road Crossing

Crossing a road is a common challenge faced by adults and children alike. It’s a routine activity, but one that must be learned and practiced. Getting it right is a matter of life and death.

Despite the critical role that parents play in teaching kids how to safely cross roads, almost nothing is known about how parents and children interact when approaching this crucial task. A University of Iowa (UI) research study aims to shed light on parent-child road crossing behaviors and, ultimately, to help lead to changes that reduce motor vehicle collisions with pedestrians, a major cause of childhood death and disability.

The National Science Foundation grant was awarded to UI faculty researchers Jodie Plumert (PI), professor in the Department of Psychological and Brain Sciences, Elizabeth O’Neal (Co-PI), assistant professor in the Department of Community and Behavioral Health, and Joseph Kearney (Co-PI), professor emeritus in the Department of Computer Science.

Common Road-Crossing Hazards

The study focuses on parents and their children, aged 6 to 8 years old, as they tackle two common road-crossing hazards: deciding whether an approaching vehicle intends to yield and deciding when to cross a stream of continuous traffic. The research is conducted in a virtual environment at the UI’s Hank Virtual Environments Laboratory in the Department of Computer Science, as well as in naturalistic environments.

“The goal of this project is to better understand how individual differences in parents’ risk-taking impacts children’s injury risk when crossing roads with traffic,” explains O’Neal. “We’ll first observe how parents cross roads on their own, without any children present, to assess their level of risk tolerance. Next, we’ll observe parents and children crossing together to see how the parent’s approach to crossing roads on their own impacts the way they teach their child to cross roads. Finally, we’ll assess how children’s experiences during joint road crossing with a parent impact their independent road-crossing behaviors.”

The individual road-crossing observations will be conducted in a virtual environment, says O’Neal, but recently developed wearable instrumentation will be used by the researchers to record parent-child interactions in real-world road crossing situations as well.

“Venturing from the laboratory to the natural environment will enrich our understanding of how parents approach teaching children complex, everyday skills, and allow us to determine the extent to which behavior in the laboratory corresponds to that in the natural environment,” says O’Neal.

Older Drivers and Licensing Renewal

Driving helps keep older adults connected to services and their communities. However, driving abilities can be affected by age-related declines in vision and cognitive functions, such as reasoning and memory. Motor vehicle crashes are the second leading cause of injury death (after falls) among adults ages 65 and older in the U.S.

In the U.S., states have a process to evaluate drivers who may no longer be fit to drive, called driver license review. A recent UI study, published in Injury Epidemiology and led by Cara Hamann, associate professor of epidemiology, examined the effects of driver license renewal policies on motor vehicle crashes and injuries among older drivers in 13 states over two decades.

The study found that states generally moved towards loosening licensing policies for older drivers. Policies investigated included renewal period, in-person renewal frequency (versus online), vision testing, knowledge testing, on-road drive testing, and mandatory physician reporting related to fitness to drive. Longer renewal periods and/or less frequent in-person renewal were associated with increased crash and injury rates for older drivers.

Police-reported crash data, state license renewal policy data, and demographic data (years 2000-2019) were analyzed from 13 Mountain West and Midwest states, including Iowa. The study population included over 19 million drivers aged 40 and older who were involved in motor vehicle crashes.

Assessing Fitness-to-Drive

Hamann said it is not clear why states may be loosening driving license renewal restrictions, but doing so is likely aligned with customer (driver) demand, especially related to having more options to renew online versus in-person.

The study found limited evidence about how well knowledge, vision, and driving tests reduced crashes and injuries among older adults because these tests varied little between the states in this study.

Losing driving privileges too soon or when unwarranted causes premature driving cessation, Hamann said, which can be better avoided by having policies that assess a driver’s abilities.

“Assessing fitness-to-drive rather than using age cut-offs is ideal because age itself is not a good indicator of driving performance,” she says. “Age cut points may be too early for some drivers, but too late for others.”

This article contains contributions from the UI Injury Prevention Research Center.

This story appeared in the fall 2025 issue of Iowa Public Health Magazine