The relationship between visibility aid use and motor vehicle related injuries among bicyclists presenting to emergency departments.
BACKGROUND
Little is known about the effectiveness of visibility aids (VAs; e.g., reflectors, lights, fluorescent clothing) in reducing the risk of a bicyclist-motor-vehicle (MV) collision.


OBJECTIVE
To determine if VAs reduce the risk of a bicyclist-MV collision.


METHODS
Cases were bicyclists struck by a MV and assessed at Calgary and Edmonton, Alberta, Canada, emergency departments (EDs) from May 2008 to October 2010. Controls were bicyclists with non-MV injuries. Participants were interviewed about their personal and injury characteristics, including use of VAs. Injury information was collected from charts. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for VAs during daylight and dark conditions, and adjusted for confounders using logistic regression. Missing values were imputed using chained equations and adjusted OR estimates from the imputed data were calculated.


RESULTS
There were 2403 injured bicyclists including 278 cases. After adjusting for age, sex, type of bicycling (commuting vs. recreational) and bicyclist speed, white compared with black (OR 0.52; 95% CI 0.28, 0.95), and bicyclist self-reported light compared with dark coloured (OR 0.67; 95% CI 0.49, 0.92) upper body clothing reduced the odds of a MV collision during daylight. After imputing missing values, white compared with black (OR 0.57; 95% CI: 0.32, 0.99) and bicyclist self-reported light compared with dark coloured (OR 0.71; 95% CI 0.52, 0.97) upper body clothing remained protective against MV collision in daylight conditions. During dark conditions, crude estimates indicated that reflective clothing or other items, red/orange/yellow front upper body clothing compared with black, fluorescent clothing, headlights and tail lights were estimated to increase the odds of a MV collision. An imputed adjusted analysis revealed that red/orange/yellow front upper body clothing colour (OR 4.11; 95% CI 1.06, 15.99) and tail lights (OR 2.54; 95% CI: 1.06, 6.07) remained the only significant risk factors for MV collisions. One or more visibility aids reduced the odds of a bicyclist MV collision resulting in hospitalization.


CONCLUSIONS
Bicyclist clothing choice may be important in reducing the risk of MV collision. The protective effect of visibility aids varies based on light conditions, and non-bicyclist risk factors also need to be considered.
Department of Paediatrics, Faculty of Medicine, University of Calgary, Alberta Children's Hospital, 2888 Shaganappi Trail NW, Calgary, Alberta T3B 6A8, Canada; Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute for Child & Maternal Health, University of Calgary, Alberta, Canada. Electronic address: brent.hagel@albertahealthservices.ca.
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Hagel
Department of Paediatrics, Faculty of Medicine, University of Calgary, Alberta Children's Hospital, 2888 Shaganappi Trail NW, Calgary, Alberta T3B 6A8, Canada.
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Romanow
Faculty of Nursing, University of Calgary, 2800 University Way N.W., Calgary, Alberta T2N 1N4, Canada.
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Morgunov
Department of Paediatrics, Faculty of Medicine, University of Calgary, Alberta Children's Hospital, 2888 Shaganappi Trail NW, Calgary, Alberta T3B 6A8, Canada.
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Embree
Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Alberta, Canada.
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Couperthwaite
School of Public Health, Alberta Centre for Injury Control & Research, University of Alberta, 4075 RTF, 8308-114 Street, Edmonton, Alberta T6G 2E1, Canada.
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Voaklander
Department of Emergency Medicine & School of Public Health, University of Alberta, 1G1.50 Walter Mackenzie Centre, 8440-112 Street, Edmonton, Alberta T6G 2B7, Canada.
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Rowe
D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D000416:Alberta; D001642:Bicycling / Q000293:injuries*; D003020:Clothing; D003116:Color; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011482:Protective Devices / Q000706:statistics & numerical data*; D012449:Safety / Q000706:statistics & numerical data*; D014600:Utilization Review / Q000706:statistics & numerical data; D014947:Wounds and Injuries / Q000453:epidemiology* / Q000517:prevention & control*; D055815:Young Adult
Bicycling; Collision; Epidemiology; Injury prevention; Visibility aids