Highway Design Impact Auto Accident Risks, Study Finds

The design of highways may play a much more important role in driver safety than previously thought, according to the findings of new research, which identifies several features that have proven to be highly effective in reducing the risk of auto accidents. 

A highway design study was presented by researchers from Brigham Young University (BYU), and published in the academic journal Sage on November 17, indicating that highways with wider shoulders, gentler curves, concrete barriers, and, surprisingly to some, higher speed limits, appear to be safer.

The research was led by Kaitlin E. Gibson, of BYU, and commissioned under the Federal Highway Administration (FHWA), to pinpoint a number of highway features that make vehicle crashes less likely. Gibson and her team looked at data on Utah’s I-15, Colorado’s I-70 highway, and Washington’s I-5, researchers found several characteristics of highways that may affect crash risks.

Researchers merged both the systemic and site specific safety approaches to determine which roadway factors associated with an increased occurrence of car crashes were also found in site specific locations with high crash occurrences.

Risk factors included the width and surface texture of roadway shoulder, roadway curvatures, soiled barriers, and whether there were landmark distractions in viewing distance from the highway.

Paved roadway shoulders that were wider provided safer areas that helped prevent vehicle crashes, as well as concrete roadway barriers. When comparing highways with concrete roadway barriers that divided oncoming traffic to those with just areas of soil between, crashes were more likely to occur on those roads without a concreted barrier.

Researchers found roadway curvatures also increased the occurrence of crashes. Due to limited visibility approaching a hill or a bend in the road may cause drivers not to begin reducing their speed soon enough, ultimately leading to more rear end collisions.

Contrary to the researchers’ expectations, highway speed limits over 65 mph were found to be safer zones than those with speed limits under 65 mph. A partial explanation for the reasoning could be that portions of roadways with slower speed limits may include curvatures or exit and on-ramp accesses.

While much of the attention to reduce vehicle crashes is directed towards changing the driver’s behavior, the study provides insight that making minor changes to roadways could play a significant factor in overall highway safety.