In a paper dealing generally with crash reductions and safety published in the September 2019 edition of the Accident Analysis and Prevention, Dr. Nicholas Fournier, Dr. Eleni Christofa, and Dr. Michael Knodler Jr. of the Civil and Environmental Engineering (CEE) Department used a combination of methods that looked at both bicycle traffic volume and automobile traffic volume to assess bicycle crash rates.
This research was funded in part through a research project awarded to Knodler and Christofa by the Safety Research Using Simulation University Transportation Center.
The study of the three CEE researchers investigates bicycle crashes using a mixed methods framework. Through this framework, the researchers estimate a monthly bicycle demand using a sinusoidal model for seasonal demand. Then the mixed methods framework utilizes corridors to expand the limited bicycle data, and the study proposes a crash rate equation using both bicycle and vehicle volumes as the exposure metric.
As the three researchers explain, crash rates are an essential tool enabling researchers and practitioners to assess whether a location is truly more dangerous for vehicles, or simply serves a higher volume of vehicles. Unfortunately, a simple crash rate is far more difficult to calculate for bicycles due to data challenges and the fact that they are uniquely exposed to both bicycle and automobile volumes on shared roadways.
As the researchers observe, “Bicycle count data, though increasingly more available, still represents a fraction of the available count data for automobiles. Further compounding on this, bicycle demand estimation methods often require more data than automobiles to account for the high variability that bicycle demand is subject to.”
In answer to this problem, as the CEE researchers say, “This paper uses a combination of mixed methods to overcome these challenges and to perform an investigation of crash rates and exposure to different traffic volumes.” (January 2020)