Individual and contextual factors associated with bicyclist injury severity in traffic incidents between bicyclists and motorists in Chile

Bicyclists are vulnerable road users who risk incurring severe injuries from traffic incidents involving motorists. However, the prevalence of severe bicycle injuries varies across countries and is not well-documented in Latin American countries. Studies from developed countries outside of Latin America have shown that individual and contextual factors are associated with severe injuries incurred by bicyclists in road traffic incidents with motorists, but it is not clear whether these factors are the same as those incurred by Latin American bicyclists. Moreover, most studies on bicyclist-motorist traffic incidents have treated injury severity as a binary variable for analysis although injuries range widely in severity. The aims of this study were to determine the prevalence of bicycle injuries from incidents between motorists and bicyclists in Chile and examine the associations between individual and contextual factors and bicyclist injury severity, treated as an ordinal outcome variable, in these incidents. Data on road traffic incidents between bicyclists and motorists from the 2016 Traffic Accident of Bicycle Riders and Consequences database of the Chilean Transport Ministry were analysed. Multilevel mixedeffects ordinal regression models were used to examine associations. In total, 81.2 % of 4093 traffic incidents between bicyclists and motorists resulted in nonfatal injuries to bicyclists and another 2.3 % resulted in fatalities. Most incidents involved collisions (84.3 %), and most were due to a motorist being distracted while driving (50.4 %). Severe bicyclist injuries were more likely when the incident involved a stationary cyclist who was struck, a collision between a moving bicycle and a moving motor vehicle, or an overturning motor vehicle striking a bicyclist (p < 0.001). Other factors included the motorist driving under the influence of alcohol (p = 0.05), the incident taking place in a mid-size community (p = 0.04), the incident occurring between 7:00 pm and 4:59 am (p < 0.01), and the injured bicyclist being under 18 years or 45+ years of age (p < 0.05). These findings suggest the need for educational programs that promote safe driving behaviour in the presence of bicyclists, better enforcement of laws and higher penalties for distracted or drunk driving, and provision of high-quality exclusive bicyclist infrastructure to address the vulnerability of the youngest and oldest bicyclists on shared roads, particularly in mid-size communities, and to provide better lighting on bikeways for evening bicycling, to reduce the high incidence of severe bicyclist injuries in motorist-bicyclist incidents.