Online Program

Impact of Weather, Road Surface and Lighting Conditions on Severity of Bicycle-Motor Vehicle Crash Injuries

Tuesday, November 3, 2015 : 3:15 p.m. - 3:30 p.m.

Morteza Asgarzadeh, PhD, Department of Environmental Health, Harvard T.H.Chan School of Public Health, Framingham, MA
Santosh K. Verma, ScD, MPH, MBBS, Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, MA
Theodore Courtney, MS, CSP, Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, MA
Giselle Sebag, MS, Harvard University, Boston, MA
Alberto J. Caban-Martinez, DO, PhD, MPH, CPH, Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL
David Christiani, MD, MPH, MS, Department of Environmental Health and Department of Epidemiology, Harvard T.H.Chan School of Public Health, Harvard University, Boston, MA
Background/Purpose: Bicycling is positive for the environment, the economy and individual health. However, safety concerns can be a barrier to cycling in the US, preventing individuals from gaining significant health benefits. We studied environmental factors contributing to the severity of injuries resulting from collisions of bicycles with motor-vehicles. 

Methods: We obtained 131,432 police reports for crashes occurring between 2000 and 2014 from the states of Illinois, Missouri, New York, North Dakota, Ohio, and the City of Minneapolis. The injuries were classified as: “severe” including fatal and incapacitating, and “moderate/minor” including non-incapacitating, possible or no injuries. Information on environmental factors such as weather, lighting level and road surface condition at the time of crash was extracted from crash reports. Logistic regression was used to assess the association between severity of injury and environmental variables.

Results/Outcomes: Of all reported crashes, 14,936 (11.4%) resulted in severe injuries. Crashes at dawn (Odds Ratio=1.63, 95% Confidence Interval 1.39, 1.91), dark - road lighted (OR 1.34, 95% CI 1.28, 1.40), and dark - road unlighted (OR =2.04, 95% CI 1.84, 2.25) were associated with higher odds of severe injuries as compared to crashes during daylight. Weather and road surface conditions were not significantly associated with severity of injuries.

Conclusion: Our findings suggest that lighting plays an important role in severe crash outcomes.  The difference between lighted and unlighted roads suggests that environmental interventions such as adding street lighting may help reduce severe crashes.

Keywords: Bicycle; Environment; Injury Severity; Crash, Lighting

Learning Areas:

Environmental health sciences
Occupational health and safety
Public health or related research

Learning Objectives:
Describe the effect of lighting on report of severe bicycle crash outcomes. Assess the role of weather and road surface conditions on report of bicycle injuries.

Keyword(s): Occupational Health and Safety, Public Health Research

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am the primary Author and lead investigator of this project. I work as a Chief Research Fellow at Harvard School of Public Health, and collaborate with Liberty Mutual Research Institute for Safety. My area of expertise is conducting injury epidemiological studies to understand ways that the design variables of the built environment can impact risk of various forms of injuries particularly bicycle-motor vehicle collisions.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.