Study of bicycling and driving behavior reveals areas for improvement

By Robbie Webber

A new report based on research by the USF Center for Urban Transportation Research and sponsored by Florida DOT details new methods for studying bicycling safety by mounting cameras and sensors on bikes ridden in naturalistic settings. The research gives us insight into the behavior of both bicyclists and drivers, the types of conflicts that occur, and route selection by bicyclists. As bicycling has become a more popular recreational activity and transportation option, this methodology holds the potential to improve safety and allow transportation professionals to target engineering, education, and enforcement activities.

Florida is an especially important target for research to improve bicycle safety because it has a bicyclist fatality rate three times higher than the national average. In just the two counties studied in the Tampa area—Hillsborough and Pinellas, which have a combined population of just over 1.2 million—there were 22 fatalities in one year. Bicycling fatalities nationally have risen faster than either pedestrian or overall traffic fatalities, and in Florida they rose over 77 percent between 2010 and 2014.

The researchers found that both bicyclists and drivers had a high rate of compliance with traffic laws and few conflicts. However, the near-misses at intersections that did occur during the study were predominantly caused by driver error when turning right, principally through failure to yield the right-of-way to bicyclists. Researchers also concluded that near-miss conflicts during passing could have been avoided with engineering solutions such as bike lanes, wider outside lanes, or dedicated facilities.

As pointed out in the report’s literature review, few studies have looked at interactions between bicyclists and drivers in a natural way, i.e., by allowing participants to pick their own routes and destinations and measuring where and when conflicts happen. This study only required that all recorded trips use roadways or adjacent sidewalks or paths instead of routes separated from traffic. The study followed bicyclist and driver compliance with traffic laws and where and how conflicts occurred by recording front, rear, and side views from the bikes. Participants completed pre-study questionnaires about their own attitudes, experiences, and behaviors. They then used a phone app to take a post-trip survey regarding trip purpose, trip comfort, route choice, close call existence, bicycle light use, etc. after each ride. This allows researchers to observe real-world conditions and look for important moments in the videos.

Data and circumstances surrounding both bicycle crashes and conflicts with drivers is difficult to gather and study because the overwhelming majority of bicycle crashes are not reported, and when they are the information in police reports may be incomplete. Minor crashes and close-calls are generally anecdotal, but these encounters are important to both the perception and reality of safety for bicyclists and may deter potential bicyclists. Understanding how and where conflicts occur can shape interventions to improve bicycle safety and reduce conflicts with drivers.

The researchers acknowledge that, although 100 participants contributed over 2,000 hours of riding and data to the study, this was only a pilot of the technology. Confirmation of the findings on bicyclist and driver behavior, route selection and preference, causes and locations of crashes and conflicts, and possible solutions to conflicts and safety issues will require more data. However, this research has demonstrated that the technology and methods used are excellent mechanisms to study these questions in a real-world setting, watching as bicyclists and drivers interact.

Robbie Webber is a Senior Associate at SSTI.