Traffic Safety Research

“Long-standing collaborations are essential to many of our projects,” noted Senior Research Associate Michelle Reyes, whose efforts often focus on safety and crash data research and analysis. Two longstanding partners for traffic safety research are the Iowa DOT and the University of Iowa Injury Prevention Research Center (IPRC).

Impact of ‘road diets’

For more than two decades, the Iowa DOT has been encouraging Iowa communities to consider converting certain four-lane streets to three lanes (also known as a “road diet”) with the aim to improve safety and reduce crashes.

Two areas of concern often raised by communities are the impacts on businesses and on emergency response. In a project recently completed for the Iowa DOT, a team of NADS and IPRC researchers including Reyes and Cara Hamann, PhD, investigated these impacts by surveying businesses and emergency responders in Iowa communities with recent lane conversions. They also analyzed emergency response time data.

The top findings included: 1. One-third of the business respondents reported positive or slightly positive effects, and another 38% thought the road conversion had no impact on their business.

2. Among emergency responders, 34% disagreed with keeping the conversion in place, while 30% agreed, and 28% were neutral.

3. Community education about what to do when emergency vehicles are on the road is important.

Many responders with negative perceptions reported that drivers didn’t know where to move to yield to the responders, resulting in blocking lanes and slowing response.

4. Lane conversions had no measurable impact on fire department response times in Cedar Rapids, Iowa.

Michelle Reyes, National Advanced Driving Simulator

Cara Hamann, PhD, Iowa Injury Prevention Research Center

Mormon Trek Boulevard in Iowa City, pictured here, was converted from four to three lanes and was included in the analysis.

Other ongoing projects

Effect of Seat Belt Use on Injury Severity for Adult Rear-Seat Occupants Injured in Motor Vehicle Crashes: Analysis of Iowa crash data from 2016–2019 found, in part, that odds of a fatal injury were 6.2 times higher when adults in the rear seat were unbelted.

Sponsor: Iowa DOT; Partners: IPRC, Governor’s Traffic Safety Bureau

A Crash Data Dictionary was developed to document the data elements collected on the Iowa crash report form. The NADS/ IPRC team reported hundreds of findings, some of which are being implemented now, that have the potential to improve crash data quality in the future.

Sponsor: Iowa DOT; Partners: IPRC, Governor’s Traffic Safety Bureau

Instrumented Farm Vehicle Roadway Study: GPS/video devices were installed on Iowa farm equipment that collected data and recorded vehicles as they approached, followed, and began to pass farm equipment.

Sponsor: CDC/NIOSH and UI Great Plains Center for Agricultural Health; Partner: Iowa State University InTrans