Enhancing Motorcycle Conspicuity Awareness in Iowa

Project status


Start date: 07/01/09
End date: 06/30/10


Principal investigators:

Student researcher:

  • Wei Zhang

About the research

Previous studies in the United States and internationally suggest that low motorcycle conspicuity, or the inability of the motorcyclist to be seen by other road users, is thought to be an important factor associated with risk of motorcycle crashes. However, there has been limited research on motorcycle conspicuity in the United States in the past two decades, while at the same time; there has been a renewed interest from states in increasing motorcycle conspicuity and motorist awareness. As such, this research revisits the motorcycle conspicuity problem by analysis of helmet-use and motorcycle crash data. First, this study reviews previous studies on motorcycle conspicuity with a focus on the effectiveness of proposed measures for enhancing motorcycle conspicuity. The major trends in motorcycle helmet use by time of day and road type for motorcyclists, as indicated from three roadside observational roadside surveys in Iowa, are also discussed. Then, using motorcycle crash data for Iowa from 2001 to 2008, this research compares single-and two-vehicle motorcycle crashes and examines the distribution of conspicuity related factors in light and dark conditions in two-vehicle crashes that could potentially relate to a collision between a motorcycle and another vehicle. The limitations of examining motorcycle conspicuity by analysis of crash data are also discussed. Finally, this report outlines recommendations based on the key findings of the study.


Report: Enhancing Motorcycle Conspicuity Awareness in Iowa (1.76 mb pdf) September 2010

Tech transfer summary: Enhancing Motorcycle Conspicuity Awareness in Iowa (1.17 mb pdf) Sep 2010



  • Iowa Department of Transportation
  • Midwest Transportation Consortium
motorcycle conspicuity
Helmet color and reflectivity improve conspicuity (image: Minnesota Department of Public Safety)