Skip to main content

Advertisement

Table 3 Studies that investigated relationships between bicyclist safety and transportation infrastructure related to roads, lanes and/or paths.

From: The impact of transportation infrastructure on bicycling injuries and crashes: a review of the literature

Reference Location; Design Infrastructure types examined Study population Outcome measures Analysis method Control method Effects observed
ROADS, LANES AND PATHS
Kaplan
(1975) Characteristics of the Regular Adult Bicycle User
[61]
United States;
Observational, non-intervention
Major roads, minor roads, on-road bike routes or lanes, off-road (including bike paths and sidewalks) 3,270 cyclists who completed a survey distributed to a random sample of League of American Wheelmen members, geographically weighted to represent the population of each state. Self-reporting (survey): 854 collisions or serious falls Calculated crash rate per million miles for different infrastructure types, based on number of miles cycled and proportion of cycling on each type. Adjusted for distance traveled. Crash rates per million miles on major streets = 114, minor roads = 105, on-road bike routes or lanes = 58, and off-road = 292. Serious crash (involving emergency department visit or hospitalization) rates per million miles on major streets = 35, minor roads = 27, on-road bike routes or lanes = 25, and off-road = 77.
Lott and Lott (1976)
Effect of Bike Lanes on Ten Classes of Bicycle-Automobile crashes in Davis, California
[62]
United States - Davis; Observational, non-intervention Roads with and without marked bike lanes 145 car-bike collisions Police reports of 145 car-bike collisions Comparison of numbers of collisions on roads with and without bike lanes, adjusting for neutral collision types. "Neutral" collision types (considered to be independent of bike lane presence) used as method to adjust for car-bike traffic on the different road types. Neutral collision types defined as those where the cyclist or motorist failed to stop or yield, or the motorist made an improper left turn. Bike lanes estimated to reduce collision frequency by 53%.
Smith and Walsh
(1988)
Safety impacts of bicycle lanes
[63]
United States - Madison;
Observational, before-after intervention
Major roads with and without marked bike lanes (one on left side of street, one on right side) 1.3-mile sections of 2 one-way arterial roads City-maintained database of traffic crashes*: 87 crashes at study sites (1,411 crashes city-wide) Compared crash counts per year before and after intervention. Adjusted for average bicycle volumes city-wide in the before and after periods. Increase in crash rates with bike lanes, especially for lane on left side of street in the initial year post-intervention. No statistically significant effect on long-term crash rates.
Tinsworth et al.
(1994) Bicycle-related injuries: Injury, Hazard, and Risk Patterns
[64]
United States;
Observational, non-intervention
Major thoroughfares, neighborhood streets, sidewalks, bike paths, unpaved surfaces (1) 420 cyclists who were injured and attended one of 90 emergency departments that report to the US Consumer Product Safety Commission, and (2) ~1250 other cyclists from a national probability sample Hospital reports of 420 injuries (emergency department visits) Multiple logistic regression, comparing infrastructure of injured cyclists (at location of injury event) and of cyclists from the national probability sample (infrastructure where cyclist rode more than 50% of the time). Adjusted for hours of bicycle use per month, age, sex, size of community, daylight vs. dawn/dusk/night. Relative risks (odds ratios) for injury by infrastructure type for adults: Major thoroughfares = 2.45; neighborhood streets (reference category) = 1; sidewalks = 1; bike paths = 0.14; unpaved surfaces = 0.11. Relative risks for children: neighborhood streets (reference category) = 1; sidewalks = 0.6; unpaved surfaces = 0.29; bike paths = 0.12.
Rodgers (1997)
Factors Associated with the Crash Risk of Adult Cyclists
[65]
United States;
Observational, non-intervention
Roads, bike paths or lanes, off-road trails, other surfaces 2,978 cyclists who completed a survey (conducted by National Family Opinion for Bicycling magazine), including adults who purchased new bicycles, screened to match US population based on geographic region, population density, household income, household size, and age. Self-reporting (survey): 280 respondents who had a crash or fell in the last 12 months Multiple logistic regression comparing odds ratios for having a collision or fall versus not, according to primary riding surface of the cyclist. Adjusted for miles traveled in warm weather months, age, sex, bicycle type, and geographic region of residence. Odds ratios for risk of being a cyclist who had collision or fall in the last year, by primary riding surface, compared to roadway (= 1.0): bike path or lane = 0.60; other surfaces = 1.28; off-road trail = 7.17.
Moritz
(1998)
Adult Bicyclists in the United States: Characteristics and Riding Experience in 1996
[66]
United States;
Observational, non-intervention
Major roads, minor roads, signed bike routes, on-street bike lanes, multiuse trails, off-road/unpaved trails, sidewalks 1,956 cyclists who completed a survey distributed to a random sample of League of American Bicyclists members, geographically weighted to represent the population of each state. Self-reporting (survey): ~680 crashes Relative danger indices calculated by dividing the proportion of crashes on a given infrastructure type by the proportion of commuting distance reported on that infrastructure. When index = 1.0, proportions of crashes and commuting distances are the same for that route type. Adjusted for distance traveled. Relative danger index by infrastructure type: major street without bike facilities = 0.66; minor street without bike facilities = 0.94; on-road bike routes = 0.51; on-road bike lanes = 0.41; multiuse trails = 1.39; off-road/unpaved trails = 4.49; "other" (mostly sidewalk) = 16.3.
Moritz
(1998)
Survey of North American Bicycle Commuters: Design and Aggregate Results
[67]
United States;
Observational, non-intervention
Major roads, minor roads, on-road bike routes & lanes, off-road bike paths, sidewalks 2,374 cyclists who completed a survey distributed via email lists, magazine advertisements, and word of mouth. Self-reporting (survey): 271 serious crashes Relative danger indices calculated by dividing the proportion of crashes on a given infrastructure type by the proportion of commuting distance reported on that infrastructure. When index = 1.0, proportions of crashes and commuting distances are the same for that route type. Adjusted for distance traveled. Relative danger index by infrastructure type: major street without bike facilities = 1.26; minor street without bike facilities = 1.04; on-road bike routes and lanes = 0.50; off-road bike paths = 0.67; "other" (mostly sidewalk) = 5.3.
Aultman-Hall and Hall (1998) Ottawa-Carleton commuter cyclist on- and off-road incident rates
[68]
Canada - Ottawa;
Observational, non-intervention
Roads, off-road paths, sidewalks 1452 commuter cyclists who completed a survey distributed on parked bicycles. Self-reporting (survey): 187 injuries, 194 collisions, 234 falls Event rates calculated per distance traveled on each infrastructure type based on GIS analyses of mapped commuting routes; relative risks for the three infrastructure types compared using Poisson distribution and Hauer statistical test. Adjusted for distance traveled. Also adjusted (via weighting) for differences in use of various infrastructure types by cyclist characteristics: weekly commute distance; left turning method; comfort on busy streets; and belonging to a cycle club or having taken a training course. Compared to cycling on-road, there were no differences in collision rates for off-road or sidewalk cycling, but the relative risks of falls were 2.1 for off-road paths and 4.0 for sidewalks, and of injury were 1.6 for off-road paths and 4.0 for sidewalks.
Aultman-Hall and Kaltenecker (1999) Toronto bicycle commuter safety rates
[29]
Canada - Toronto;
Observational, non-intervention
Roads, off-road paths, sidewalks 1196 commuter cyclists who completed a survey distributed on parked bicycles. Self-reporting (survey): 182 injuries, 300 collisions 203 falls Event rates calculated per distance traveled on each infrastructure type based on GIS analyses of mapped commute routes; relative risks for the three infrastructure types compared using Poisson distribution and Hauer statistical test. Adjusted for distance traveled. Also adjusted (via weighting) for differences in use of various infrastructure types by cyclist characteristics: age; sex; weekly commute distance; and comfort on busy streets. Compared to cycling on-road, relative risks of collisions were 3.5 for off-road and 2.0 sidewalk cycling, of falls were 1.5 for off-road paths and 9.0 for sidewalks, and of injury were 1.8 for off-road paths and 6.4 for sidewalks.
ROAD DESIGN CHARACTERISTICS
Klop and Khattak (1999)
Factors Influencing Bicycle Crash Severity on Two-Lane, Undivided Roadways in North Carolina
[69]
United States - North Carolina;
Observational, non-intervention
Characteristics of 2-lane undivided roads: curve vs. straight; level vs. grade; right shoulder width; intersection or not; street lighting 1,025 collisions with motor vehicles. Police reports of bicycle collisions (recorded in the Highway Safety Information System) identifying injury severity†. Classified as property damage only, pain, non-incapacitating, incapacitating, and fatal. Multivariate ordered probit model comparing the 5 levels of injury severity. Adjusted for traffic volume, speed limit, year, rural-urban, weather, daylight. More severe injuries were significantly associated with the following infrastructure characteristics: grades on both curved and straight roads; and unlit roads at night. Other factors associated with higher injury severity included: higher speed limits; lower average annual daily traffic; and fog.
Allen-Munley et al.
(2004) Logistic model for rating urban bicycle route safety
[70]
United States - Jersey City;
Observational, non-intervention
Width and grade of roads, one-way versus two-way road configuration, highway versus non-highway road type 314 injuries resulting from collisions with motor vehicles. Police reports of 314 bicycle crashes, identifying injury severity†. Classified as property damage only, minor and serious. Ordinal logistic regression comparing the three levels of injury severity. Adjusted for whether child or adult, traffic volume per lane, household income, population density, land use, weather, and daylight. More severe injuries were significantly associated with wider roads, perceptible grades, and one-way streets, pavement not resurfaced in last 10 years, and highway road type (the first three variables at p < 0.05, the latter three at p < 0.10).
ROAD SURFACES
Rivara et al. (1997) Epidemiology of bicycle injuries and risk factors for serious injury
[16]
United States - Seattle;
Observational, non-intervention
Surface type: paved vs. unpaved 3390 injured cyclists who completed a questionnaire about demographic characteristics, cycling experience, crash circumstances, and helmet use and fit. Emergency department, hospital and medical examiner records of injuries, classified using the injury severity† score (ISS) Univariate and multivariate logistic regression comparing cyclists with severe injuries (ISS > 8) to those with less severe injuries. Adjusted for age, motor vehicle involvement, speed, helmet use. Decreased risk of severe injury on unpaved surfaces (odds ratio = 0.7, not statistically significant). Motor vehicle involvement was strongest risk factor (odds ratio = 4.6).
SIDEWALKS
Wachtel and Lewiston (1994)
Risk-factors for bicycle motor-vehicle collisions at intersections
[71]
United States - Palo Alto;
Observational, non-intervention
Sidewalks vs. roadways 89 bicycle-motor vehicle collisions at intersections or junctions on three major arterial roads. Police reports of 89 collisions Relative risk of collisions for cyclists on sidewalks vs. on roadway. Risk calculations used 8-hour bicyclist counts at 9 intersections (7 signalized and 2 with stop signs) on the 3 arterials. Adjusted for age (whether child < 18 or adult), sex, and direction of travel (with or against motor vehicle traffic). Cycling on the sidewalk is associated with higher risk (RR = 1.8). The elevated risk on sidewalks is almost exclusively related to cycling against traffic (RR = 1.9) vs. with traffic (RR = 0.9).
STREET LIGHTING
Kim et al. (2007) Bicyclist injury severities in bicycle-motor vehicle crashes
[72]
United States - North Carolina;
Observational, non-intervention
Street lighting, straight versus curved roadway, street configuration (one-way, two-way, divided or not) 2934 injuries resulting from collisions between a single motorist and a bicyclist. Police reports of injury severity†. Classified as fatal; incapacitating; non-incapacitating; possible or no injury. Multinomial logit
model, comparing the probability of four injury severity outcomes
Adjustment for all factors included in model: bicyclist age, intoxication, helmet use; driver intoxication; vehicle speed and type; crash characteristics including fault and directions of travel; land use; time of day; weather. Infrastructure-related determinants that increased the probability of severe injury in an crash were: unlit roads at night; curved road geometry; and undivided street configuration.
Wanvik (2009)
Effects of road lighting: an analysis based on Dutch crash statistics 1987-2006
[73]
The Netherlands;
Observational, non-intervention
Road lighting on rural roads ~125,000 bicycle crashes resulting in injury from 1987-2006. Police reports of ~125,000 injuries Odds ratio estimating risk of crash in darkness versus daylight on lit versus unlit roads. Adjusted for hour of the day, darkness, and season, by summing log odds ratios calculated separately for these factors. Log odds ratios were weighted in inverse proportion to the variance of the odd ratio. Presence of lighting on rural roads reduces bicyclist injuries by ~60%.
  1. * This study used only the term "accident" to describe crashes (collisions and/or falls) that may or may not have resulted in injury. We have substituted the words "injury", "crash", "collision" and/or "fall" based on our reading of the studies, as explained in the "Safety terminology" section of the text.
  2. † Injury severity does not reflect risk of an incident, but rather the outcome of the incident once it occurs.