Roadside Vegetation / Clear Zone Design

Funding Source: Safer Sim

Title: The Effect of Roadside Vegetation and Clear Zone Design on Driver Behavior


Status: Completed

Summary: Roadside vegetation provides a myriad of environmental and psychological benefits to drivers. Research has shown that, although natural landscapes cause less stress and frustration to the driver, the same vegetation may increase the severity of run-off-the-road crashes. This study evaluates the relationship between clear zone design and the presence of roadside vegetation on driver speed, lateral positioning, and drivers’ visual scan patterns. A driving simulator was utilized to test six combinations of clear zone sizes and roadside vegetation densities. Participants’ driving performance was measured throughout the virtual drive. While there were no statistically significant differences between drivers’ speeds, the speed trends that were found correlate to statistically significant observations in previous research, further validating the effect of clear zone size on driver speed. Along left curves, drivers drove closer to the centerline when there were trees near the edge of the road. Based upon the recorded drivers’ eye movements, the horizontal scan pattern did not significantly change between combinations, suggesting that drivers use their peripheral vision to monitor potential hazards.

Team: Michael Knodler, Don Fisher

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