The potential of vehicle and road infrastructure interventions in fatal bicyclist accidents on Swedish roads—What can in-depth studies tell us?

Abstract

Objective: The objective of this article is to describe the characteristics of fatal crashes with bicyclists on Swedish roads in rural and urban areas and to investigate the potential of bicycle helmets and different vehicle and road infrastructure interventions to prevent them. The study has a comprehensive approach to provide road authorities and vehicle manufacturers with recommendations for future priorities.

Methods: The Swedish Transport Administration’s (STA) in-depth database of fatal crashes was used for case-by-case analysis of fatal cycling accidents (2006–2016) on rural (n?=?82) and urban (n?=?102) roads. The database consists of information from the police, medical journals, autopsy reports, accident analyses performed by STA, and witness statements. The potential of helmet use and various vehicle and road infrastructure safety interventions was determined retrospectively for each case by analyzing the chain of events leading to the fatality. The potential of vehicle safety countermeasures was analyzed based on prognoses on their implementation rates in the Swedish vehicle fleet.

Results: The most common accident scenario on rural roads was that the bicyclist was struck while cycling along the side of the road. On urban roads, the majority of accidents occurred in intersections. Most accidents involved a passenger car, but heavy trucks were also common, especially in urban areas. Most accidents occurred in daylight conditions (73%). Almost half (46%) of nonhelmeted bicyclists would have survived with a helmet. It was assessed that nearly 60% of the fatal accidents could be addressed by advanced vehicle safety technologies, especially autonomous emergency braking with the ability to detect bicyclists. With regard to interventions in the road infrastructure, separated paths for bicyclists and bicycle crossings with speed calming measures were found to have the greatest safety potential. Results indicated that 91% of fatally injured bicyclists could potentially be saved with known techniques. However, it will take a long time for such technologies to be widespread.

Conclusions: The majority of fatally injured bicyclists studied could potentially be saved with known techniques. A speedy implementation of important vehicle safety systems is recommended. A fast introduction of effective interventions in the road infrastructure is also necessary, preferably with a plan for prioritization.     

Predicting bicycle helmet wearing intentions and behavior among adolescents

INTRODUCTION: Cycling accidents in Australia, especially those resulting in head injuries, are a substantive cause of death and disability; but despite legislation and evidence that helmets reduce the risk of head injury, few adolescents wear them. METHOD: This study employed a revised version of the Theory of Planned Behavior (TPB; [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211]) to investigate the determinants of helmet use among a sample of adolescents. Participants in the initial data collection were 294 high school students in Year 8 and Year 11, with 266 completing a follow-up questionnaire measuring behavior over the previous two weeks. RESULTS: Social norms, perceptions of control, and past behavior significantly predicted intentions to use helmets and perceptions of control and past behavior predicted actual helmet use. CONCLUSIONS: Strengthening the routine of helmet use and building young people's confidence that they can overcome any perceived barriers to helmet use will improve adherence to helmet wearing behavior.     

An in-depth analysis of self-reported cycling injuries in single and multiparty bicycle crashes in Denmark

Introduction: Cycling is one of the main forms of transportation in Denmark. However, while the number of traffic crash fatalities in the country has decreased over the past decade, the frequency of cyclists killed or seriously injured has increased. The high rate of serious injuries and fatalities associated with cycling emphasizes the increasing need for mitigating the severity of such crashes. Method: This study conducted an in-depth analysis of cyclist injury severity resulting from single and multiparty bicycle-involved crashes. Detailed information was collected using self-reporting data undertaken in Denmark for a 12-month period between 1 November 2012 and 31 October 2013. Separate multilevel logistic (MLL) regression models were applied to estimate cyclist injury severity for single and multiparty crashes. The goodness-of-fit measures favored the MLL models over the standard logistic models, capturing the intercorrelation among bicycle crashes that occurred in the same geographical area. Results: The results also showed that single bicycle-involved crashes resulted in more serious outcomes when compared to multiparty crashes. For both single and multiparty bicycle crash categories, non-urban areas were associated with more serious injury outcomes. For the single crashes, wet surface condition, autumn and summer seasons, evening and night periods, non-adverse weather conditions, cyclists aged between 45 and 64 years, male sex, riding for the purpose of work or educational activities, and bicycles with light turned-off were associated with severe injuries. For the multiparty crashes, intersections, bicycle paths, non-winter season, not being employed or retired, lower personal car ownership, and race bicycles were directly related to severe injury consequences. Practical Applications: The findings of this study demonstrated that the best way to promote cycling safety is the combination of improving the design and maintenance of cycling facilities, encouraging safe cycling behavior, and intensifying enforcement efforts.     

Bicycle helmet effectiveness is not overstated

Objective: The objective of this study was to discuss the challenges in estimating bicycle helmet effectiveness from case–control studies of injured cyclists and to estimate helmet effectiveness from cases and available exposure data.

Methods: Data were extracted from studies of cyclists in Seattle; Victoria and New South Wales, Australia; and The Netherlands. Estimates of helmet use were used as exposure to compute relative risks for Seattle and Victorian data. Cycling distance data are routinely collected in The Netherlands; however, these data cannot be disaggregated by helmet use, which makes it unsuitable for estimating helmet effectiveness. Alternative controls were identified from larger cohorts for the Seattle and New South Wales cases.

Results: Estimates of helmet effectiveness were similar from odds ratios (ORs) using hospital controls or from relative risks (RRs) using helmet use estimates (Seattle: OR = 0.339, RR = 0.444; Victoria: OR = 0.500, RR = 0.353). Additionally, the odds ratios using hospital controls were similar when controls were taken from a larger cohort for head injury of any severity (Seattle: OR = 0.250, alt OR = 0.257; NSW: OR = 0.446, alt OR = 0.411) and for serious head injury (Seattle: OR = 0.135, alt OR = 0.139; NSW: OR = 0.335, alt OR = 0.308). Although relevant exposure data were unavailable for The Netherlands, the odds ratio for helmet effectiveness of those using racing, mountain, or hybrid bikes was similar to other estimates (OR = 0.371).

Conclusions: Despite potential weaknesses with case–control study designs, the best available evidence suggests that helmet use is an effective measure of reducing cycling head injury.     

Protection performance of bicycle helmets

IntroductionThe evaluation of head protection systems needs proper knowledge of the head impact conditions in terms of impact speed and angle, as well as a realistic estimation of brain tolerance limits. In current bicycle helmet test procedures, both of these aspects should be improved. Method: The present paper suggests a bicycle helmet evaluation methodology based on realistic impact conditions and consideration of tissue level brain injury risk, in addition to well known headform kinematic parameters. The method is then applied to a set of 32 existing helmets, leading to a total of 576 experimental impact tests followed by 576 numerical simulations of the brain response. Results: It is shown that the most critical impacts are the linear-lateral ones as well as the oblique impact leading to rotation around the vertical axis (ZRot), leading both to around 50% risks of moderate neurological injuries. Based on this test method, the study enables us to compare the protection capability of a given helmet and eventually to compare helmets via a dedicated rating system.     

Can social psychological models be used to promote bicycle helmet use among teenagers? A comparison of the Health Belief Model, Theory of Planned Behavior and the Locus of Control

PROBLEM: The bicycle helmet use rate is still low among teenagers despite the cumulating evidence that bicycle helmets can prevent cyclists from serious injuries and death. The objective of this study was to investigate the usefulness of the Health Belief Model (HBM; Health Education Monographs, 2 (1974) (1), Theory of Planned Behavior (TPB; Ajzen, I. (1988). Attitudes, personality and behavior. Open University Press, Milton Keynes) and Locus of Control model (LC; Psychological Monographs, (1966) (80) in understanding the intention to use bicycle helmet use among bicycle helmet owners. METHOD: Data were collected at two schools in Helsinki, Finland. Students (N=965) completed a questionnaire including three social psychological models applied to helmet use. Models were compared by structural equation modeling techniques. SUMMARY: Results showed that the TPB and LC model fitted the data well, whereas fit of the HBM model was lower than the fit of TPB and LC models. All components of TPB and external LC orientation were significantly related to the intention to use a helmet. TPB together with LC model provide a promising theoretical framework for helmet use promotion campaigns. Practical suggestions for future bicycle helmet campaigns were provided.     

Geo-spatial and log-linear analysis of pedestrian and bicyclist crashes involving school-aged children

PROBLEM: There is a growing concern with the safety of school-aged children. This study identifies the locations of pedestrian/bicyclist crashes involving school-aged children and examines the conditions when these crashes are more likely to occur. METHOD: The 5-year records of crashes in Orange County, Florida where school-aged children were involved were used. The spatial distribution of these crashes was investigated using the Geographic Information Systems (GIS) and the likelihoods of crash occurrence under different conditions were estimated using log-linear models. RESULTS: A majority of school-aged children crashes occurred in the areas near schools. Although elementary school children were generally very involved, middle and high school children were more involved in crashes, particularly on high-speed multi-lane roadways. Driver's age, gender, and alcohol use, pedestrian's/bicyclist's age, number of lanes, median type, speed limits, and speed ratio were also found to be correlated with the frequency of crashes. DISCUSSION: The result confirms that school-aged children are exposed to high crash risk near schools. High crash involvement of middle and high school children reflects that middle and high schools tend to be located near multi-lane high-speed roads. IMPACT ON INDUSTRY: The pedestrian's/bicyclist's demographic factors and geometric characteristics of the roads adjacent to schools associated with school children's crash involvement are of interest to school districts.     

Factors related to youth self-efficacy for injury prevention bicycle skills

Introduction: Bicycle riding is a common activity for children, but they are prone to bicycle-related injuries. It is well-established that injury prevention measures such as wearing a helmet and correctly riding a bicycle can reduce the severity of an injury and the likelihood of having an accident. However, how to increase bicycle injury prevention behaviors among children, who collectively fail to engage in injury prevention behaviors, is less well understood. Self-efficacy is consistently predictive of injury prevention behavior, making it an important approach to understanding injury prevention skills among this key population. The objective of this study was to explore and identify factors internal to the child as well as factors about his or her environment that predict a child’s self-efficacy for injury prevention skills. Method: Two generalized linear mixed effects models were created from survey data collected from elementary school students (n = 2,255) as part of a school-based bicycle education program. Models focused on self-efficacy for riding a bicycle and self-efficacy for wearing a helmet correctly. Results: In both models, road safety knowledge, opportunity for skill building through owning appropriate equipment (a bicycle or helmet), and situation through perception of neighborhood safety were predictive. The analyses reveal these variables as key factors for greater confidence, with feeling safe riding in the neighborhood, in particular, emerging as highly predictive of self-efficacy for injury prevention skills. Conclusions: These findings highlight the interplay of individual and environmental factors within confidence for injury prevention behavior. Given self-efficacy’s strong relationship to prevention behavior, these findings indicate actionable strategies. Practical Applications: The key factors highlighted in this study can be used by policymakers to target specific areas (e.g., neighborhood safety) to promote self-efficacy and thus improve injury prevention. These factors can also inform strategies for establishing safety skills in bicycle-safety education programs.