Perceptions of vulnerable roadway users on autonomous vehicle regulations.

INTRODUCTION: Development and implementation of autonomous vehicle (AV) related regulations are necessary to ensure safe AV deployment and wide acceptance among all roadway users. Assessment of vulnerable roadway users' perceptions on AV regulations could inform policymakers the development of appropriate AV regulations that facilitate the safety of diverse users in a multimodal transportation system. METHOD: This research evaluated pedestrians' and bicyclists' perceptions on six AV regulations (i.e., capping AV speed limit, operating AV in manual mode in the sensitive areas, having both pilot and co-pilot while operating AVs, and three data-sharing regulations). In addition, pedestrians' and bicyclists' perceptions of testing AVs in public streets were evaluated. Statistical testing and modeling techniques were applied to accomplish the research objectives. RESULTS: Compared to the other AV regulations assessed in this research, strong support for AV-related data sharing regulations was identified. Older respondents showed higher approval of AV testing on public roadways and less support for regulating AVs. AV technology familiarity and safe road sharing perceptions with AVs resulted in lower support for AV regulations. CONCLUSIONS: Policymakers and AV technology developers could develop effective educational tools/resources to inform pedestrians and bicyclists about AV technology reliability and soften their stance, especially on AV regulations, which could delay technology development. PRACTICAL APPLICATIONS: The findings of this research could be used to develop informed AV regulations and develop policies that could improve pedestrians' and bicyclists' attitudes/perceptions on regulating AVs and promoting AV technology deployments.

To helmet or not to helmet: a global perspective on the bicycle compulsory protective helmet law.

Child injury from bike accidents is a significant component of morbidity, mortality and health expenditure in many countries. Universal use of bicycle helmets by children could prevent between 135 and 155 deaths, and between 39,000 and 45,000 head injuries annually. Surprisingly, epidemiologic data indicate a worldwide low prevalence of helmet use. A global view on the law on the compulsory use of safety helmets involving 58 different countries is provided in order to bring this critical debate back to the table. A broad search using "bicycle-related injuries," "bicycle helmet," "bicycle helmet legislation" and "compulsory bicycle helmet law by countries" was performed in order to identify and select the most pertinent information on the issue as well as all the information available on bicycle helmet law by countries. The papers identified permitted us to assess the main topics related to the use of bicycle helmets discussed over the years which are still relevant and without consensus even today, as well as alphabetically enlist the approach of 58 countries to the compulsory helmet law. Our review on the many faces of the bicycle helmet use (pros and cons), personal aspects, head injuries, legislation, promotion, socioeconomic influence, and finally a global view on the law on the compulsory use of safety helmets allowed us to bring here many suggestions and a few conclusions, mainly because "to helmet or not to helmet" should not be a question anymore. A universal consensus on their compulsory use has to be achieved in order to improve children's safety.

Red-light running behavior of delivery-service E-cyclists based on survival analysis.

OBJECTIVE: The primary objective of this study is to explore the red-light running behavior of delivery-service E-cyclists, including differences with regular E-cyclists and influencing factors. METHODS: A total of 2173 E-cyclists in Shanghai were observed, with a mix of 51.8% regular E-cyclists and 48.2% delivery-service E-cyclists. Survival analysis was used to establish the model to resolve the issue of censored data of the waiting time of E-cyclists at an intersection. The Kaplan-Meier estimator was adopted to examine the significance of the difference between regular E-cyclists and delivery-service E-cyclists on red-light running behavior. A Cox proportional hazards model with six potential influencing factors was developed to estimate the red-light running probability of delivery-service E-cyclists. RESULTS: The violation rate of the red-light running behavior is almost 40% higher for delivery-service E-cyclists when compared to that for regular E-cyclists. The results show four factors that increase the hazard rate of red-light violation for delivery-service E-cyclists: being male, visual search (i.e., head movement), waiting beyond the stop line, and existence of red-light running of other (E-)cyclists. Additionally, they show one factor decreases the hazard rate of red-light violation: group size. CONCLUSIONS: Waiting position, violation of the law by other cyclists, and group size play an important role in red-right running behavior. The hazard rates of running red-light by delivery-service E-cyclists increased by 62% and 33% when they wait near motorized lanes and when other individuals violate traffic rules, respectively. The hazard rates reduced by 50% when there are more than five waiting cyclists.

Driver knowledge of cycling-related road rules in Queensland, Australia.

OBJECTIVES: Violations of road rules are common in bicycle-motor vehicle crashes, but little is known about how much this results from lack of knowledge of the rules. This article addresses the research questions of how well do drivers know the road rules related to interacting with cyclists, and what factors influence their level of knowledge. METHODS: An online survey compared drivers who reported riding bicycles on Queensland roads in the previous 12 months ("cyclists": n = 2,839) and those who did not ("drivers": n = 4,070). A list of 10 plausible road rules (four were not actual rules) relating to interactions between motor vehicles and bicycles was presented, and participants were asked "Which of the following road rules applies in Queensland?" The response options for each item were "Yes," "No," and "I don't know". RESULTS: The percentages correct varied markedly across the rules, from 86.5% to 38.7% for cyclists and from 72.2% to 20.9% for drivers. Incorrect responses were generally more common than "Don't know" responses (cyclists: 22.3% incorrect, 9.8% "Don't know"; drivers: 29.9% incorrect, 19.6% "Don't know"). The hierarchical regression analysis confirmed that cyclists had better road rule knowledge than drivers. In the cyclist-only model, more frequent riding was significantly associated with better road rule knowledge but explained only 3% of the total variance. Older cyclists and those living in more urbanized areas had better knowledge but age and location of residence together added only 1% to the variance explained. In the driver-only model, knowledge was better for male, older, more educated participants and those living in more urbanized areas but these variables together accounted for only 5% of the variance. CONCLUSIONS: The results of this study suggest that improving knowledge of some current road rules could be beneficial for cycling safety but for some other rules, improved knowledge could be detrimental for cycling safety and changing the rules to reflect shared perceptions of safe behavior may be more beneficial. For each of the rules, further research is needed to examine the links between knowledge and compliance, and the influence of compliance on the risks of bicycle-motor vehicle crashes and near misses.

Childhood cycling fatalities in South Australia before and after the introduction of helmet legislation.

In the years following the introduction of legislation in Australian states mandating the wearing of helmets, there was a decline in the number of deaths. Debate has occurred, however, as to why this occurred. The Traffic Accident Reporting System database, which records data for all police-reported crashes in South Australia, was searched for all cases of deaths occurring in the state in bicycle riders aged ≤14 years from January 1982 to December 2001. The numbers of deaths were then compared over the 10-year periods before (1982-1991) and after (1992-2001) the introduction of helmet legislation, and also on a yearly basis from 1982 to 2001. Comparing the numbers of deaths in the two periods before and after helmet legislation in 1991 showed a marked decrease in cases from 36 to 12. However, in examining the numbers of deaths per year in greater detail, it appears that these were already steadily reducing from nine cases per year in 1982 (2.9/100,000) to two cases in 1991 (0.67/100,000) to a virtual plateau after 1991 (ranging from 0 to 2 cases annually). It seems that the introduction of compulsory bicycle helmet wearing in South Australia came at a time when the numbers of child cyclist deaths had been steadily declining over the preceding decade. While helmet wearing clearly protects children who are still riding bicycles, the reasons for the reduction in numbers of deaths appears more complex than legislative change and likely involves a subtle interaction with other behavioural and societal factors and preferences.

Cost-effectiveness of mandatory bicycle helmet use to prevent traumatic brain injuries and death.

BACKGROUND: Traumatic brain injury (TBI) is the main cause of mortality and severe morbidity in cyclists admitted to Dutch emergency departments (EDs). Although the use of bicycle helmets is an effective way of preventing TBI, this is uncommon in the Netherlands. An option to increase its use is through a legal enforcement. However, little is known about the cost-effectiveness of such mandatory use of helmets in the Dutch context. The current study aimed to assess the cost-effectiveness of a law that enforces helmet use to reduce TBI and TBI-related mortality. METHODS: The cost-effectiveness was estimated through decision tree modelling. In this study, wearing bicycle helmets enforced by law was compared with the current situation of infrequent voluntary helmet use. The total Dutch cycling population, consisting of 13.5 million people, was included in the model. Model data and parameters were obtained from Statistics Netherlands, the National Road Traffic Database, Dutch Injury Surveillance System, and literature. Effects included were numbers of TBI, death, and disability-adjusted life years (DALY). Costs included were healthcare costs, costs of productivity losses, and helmet costs. Sensitivity analysis was performed to assess which parameter had the largest influence on the incremental cost-effectiveness ratio (ICER). RESULTS: The intervention would lead to an estimated reduction of 2942 cases of TBI and 46 deaths. Overall, the incremental costs per 1) death averted, 2) per TBI averted, and 3) per DALY averted were estimated at 1) € 2,002,766, 2) € 31,028 and 3) € 28,465, respectively. Most favorable were the incremental costs per DALY in the 65+ age group: € 17,775. CONCLUSIONS: The overall costs per DALY averted surpassed the Dutch willingness to pay threshold value of € 20,000 for cost-effectiveness of preventive interventions. However, the cost per DALY averted for the elderly was below this threshold, indicating that in this age group largest effects can be reached. If the price of a helmet would reduce by 20%, which is non-hypothetical in a situation of large-scale purchases and use of these helmets, the introduction of this regulation would result in an intervention that is almost cost-effective in all age groups.

Twenty miles per hour speed zones reduce the danger to pedestrians and cyclists.

The studyCleland LC, McComb L, Kee F, et al. Effects of 20 mph interventions on a range of public health outcomes: a meta-narrative evidence synthesis. J Transp Health 2019. doi:10.1016/j.jth.2019.100633This project was funded by the NIHR Policy Research Programme (project number 17/149/19).To read the full NIHR Signal, go to: https://discover.dc.nihr.ac.uk/content/signal-000853/twenty-mph-speed-zones-reduce-the-danger-to-pedestrians-and-cyclists.

Adoption of municipal bylaw legislating mandatory helmet use for cyclists under the age of 18: impact on cycling and helmet use. / Adoption d'un règlement municipal pour obliger les moins de 18 ans à porter un casque à vélo : effet sur la pratique du vélo et le port du casque.

INTRODUCTION: Bicycle helmet use is recognized as an effective way to prevent head injuries in cyclists. A number of countries have introduced legislation to make helmets mandatory, but many object to this type of measure for fear that it could discourage people, particularly teenagers, from cycling. In 2011, the City of Sherbrooke adopted a bylaw requiring minors to wear a bicycle helmet. The objective of this study was to assess the impact of this bylaw on cycling and bicycle helmet use. METHODS: The impact of the bylaw was measured by comparing the evolution of bicycle helmet use among youth aged 12 to 17 years in the Sherbrooke area (n = 248) and in three control regions (n = 767), through the use of logistic regression analyses. RESULTS: Cycling rates remained stable in the Sherbrooke area (going from 49.9% to 53.8%) but decreased in the control regions (going from 59.1% to 46.3%). This difference in evolution shows that cycling rates increased in the Sherbrooke area after the adoption of the bylaw, compared to the control regions (odds ratio [OR] of the interaction term: 2.32; 95% confidence interval [CI]: 1.01-5.35). With respect to helmet use, a non-statistically significant upward trend was observed in the Sherbrooke area (going from 43.5% to 60.6%). This figure remained stable in the control regions (going from 41.5% to 41.9%). No significant difference was observed in the evolution of helmet use between the two groups (OR of the interaction term of 2.70; 95% CI: 0.67-10.83). CONCLUSION: After the bylaw was adopted, bicycle use among youth aged 12 to 17 years in the Sherbrooke area remained stable and helmet used increased, though not significantly.

A Transport Policy Whose Injury Impacts May Go Unnoticed: More Walking, Cycling and Use of Public Transport.

It is an objective of transport policy in many countries and cities to promote walking, cycling and the use of public transport. This policy seeks to improve public health and reduce emissions contributing to global warming. It is, however, very likely that more walking, cycling and use of public transport will be associated with an increase in traffic injury. Moreover, it is likely that most of this increase will go unnoticed and not be recorded in official road accident statistics. Official statistics on traffic injury are known to be very incomplete as far as injuries to pedestrians, cyclists and public transport passengers are concerned. This incompleteness is a problem when assessing health impacts of more walking, cycling and travel by public transport. In this paper, studies made in the city of Oslo, Norway (population 700,000) are used to develop numerical examples showing how the estimated real and recorded number of injuries may change when 10% of person km of travel performed by car are transferred to walking, cycling or public transport. It is shown that not more than about 2% of the estimated change in the actual number of injured road users will be recorded by official statistics on traffic injury.

Speeding behavior and speed limits for heterogeneous bicycle flow.

Objective: Speed limits for motorized vehicles are widely used to reduce noise and promote road safety. Unfortunately, there is little research on speed limits for bicycles, especially for electric bicycles. This article aims to analyze the speeding behavior and propose the suggested speed limit values for electric bicycles. Methods: Field speed data were collected from 11 segments of separated bicycle lanes in Hangzhou, China. The speeding behavior of different types of bicycles was analyzed under different speed limits. Mixed logistic models are proposed to model speeding behavior and its influencing factors. Eighty-fifth percentile speeds under different conditions were calculated as speed limits. Stepwise regression models are proposed to model the relationships between the 85th percentile speeds and their influencing factors, and speed limits for different types of bicycles were determined. Results: It is recommended that the speed limits for pure electric bicycle traffic be set as 25-30 km/h and 30-35 km/h for bicycle lanes with widths less than 3 m and greater than 3 m, respectively. The recommended speed limit for heterogeneous bicycle flows is 25 km/h. Conclusions: The suggested speed limit values for different bicycle traffic flow can help to improve speed limit laws and policies for bicycle traffic.

Local All-Age Bicycle Helmet Ordinances in the United States: A Review and Analysis.

Bicycle helmets protect against head injury. Mandatory helmet laws likely increase their use. Although 21 states and Washington, DC have mandatory helmet laws for youth (variously defined) bicyclists, no U.S. state has a mandatory helmet law that applies to all ages; however, some localities have all-age helmet laws for bicyclists. This study abstracted local helmet laws applicable to all-ages to examine their elements.

The impact of bicycle helmet legislation on cycling fatalities in Australia.

BACKGROUND: Australian bicycle helmet laws were first introduced in Victoria in July 1990 and the remaining Australian states, Australian Capital Territory and Northern Territory by July 1992. Previous research on helmet legislation has focused on changes in helmet wearing and bicycle-related head injury. Although it is generally accepted that bicycle helmets can reduce the risk of fatality due to head injury, there has been little research assessing the impact of helmet legislation on cycling fatalities. METHODS: An interrupted time series approach was used to assess the impact of bicycle helmet legislation on yearly-aggregated rates of bicycle-related fatalities per population from 1971 to 2016. RESULTS: Immediately following bicycle helmet legislation, the rate of bicycle fatalities per 1 000 000 population reduced by 46% relative to the pre-legislation trend [95% confidence interval (CI): 31, 58]. For the period 1990-2016, we estimate 1332 fewer cycling fatalities (95% CI: 1201, 1463) or an average of 49.4 per year (95% CI: 44.5, 54.2). Reductions were also observed for pedestrian fatalities; however, bicycle fatalities declined by 36% relative to pedestrian fatalities (95% CI: 12, 54). CONCLUSIONS: In the absence of robust evidence showing a decline in cycling exposure following helmet legislation or other confounding factors, the reduction in Australian bicycle-related fatality appears to be primarily due to increased helmet use and not other factors.

Investigating factors affecting riders' behaviors of occupying motorized vehicle lanes on urban streets.

The violation activity of non-motorized vehicles riding in motorized vehicle lanes interferes roadway traffic serious, as it can not only seriously depreciate the efficiency of motorized vehicle traffic, but also raise possibility of triggering traffic accidents. The primary purpose of this study was to investigate intrinsic features of unlawful non-motorized vehicles' violation behaviors of riding on motorized vehicle lanes. The binary logistic regression model was proposed to find inherent reasons of triggering such misbehaviors. The misbehaviors of non-motorized vehicles (including regular bicycles, electric bicycles and human-powered tricycles) at seven sections, located at Hefei, China, were collected and studied. The experimental results indicate that male traffic participants exhibit higher rates of traffic violations than females, and rainy days shows higher misbehaviors than sunny and cloudy days. Another finding is that morning peak violation rate is higher than the evening peak and non-peak hours due to the fact people are in hurry for work. The traffic density of motorized vehicles and the traffic density of non-motorized vehicles strongly affect illegal occupancy behavior. The effect of dividing strip type and non-motorized vehicle type on lane illegal occupancy behavior are significant. We find that the average lane illegal occupancy rate of non-motorized vehicle is 36.1% which suggests that over one-third of non-motorized riders violate traffic rules. The findings of this study can help traffic authorities, road construction departments and traffic participants perform effective and efficient measurements to improve road traffic safety.

(E-)Cyclists running the red light - The influence of bicycle type and infrastructure characteristics on red light violations.

Red light running is one of the most common traffic violations among cyclists. From different surveys, we know that about 40% of all cyclists run a red light at least occasionally. However, specific data on red light running of e-bike riders (pedelec and S-pedelec riders), a population of cyclists that has been growing steadily in the past few years in Germany and elsewhere, is largely missing. Similarly unclear is the role of the used infrastructure (e.g., carriageway or bike path) or the intersection type on the riders' propensity to run the red light. The goal of this study was to investigate the red light running behaviour of three different bicycle types (bicycle, pedelec, S-pedelec) in Germany, with specific focus on various infrastructure characteristics. We reanalysed data obtained in a naturalistic cycling study, in which we observed 90 participants riding their own bicycles (conventional bicycles, pedelecs, S-pedelecs) on their daily trips over four weeks each. The video material of these trips was annotated and analysed with regard to red light running. Overall, our participants experienced nearly 8000 red light situations. In 16.3% of these situations, they ran the red light, with nearly identical rates for cyclists, pedelec and S-pedelec riders. Red light running rates were lowest when cyclists rode on the carriageway, while the complexity of the intersection appeared to play a role as well. In general, red light running was more common when riders were about to turn right instead of turning left or riding straight through the intersection. Interestingly, we also observed a considerable number of cases in which the riders changed their used infrastructure (e.g., from the carriageway onto the pavement) to avoid a red light.

State Safe Bicycle Passing Laws.

(1) There were 840 bicyclist traffic deaths in 2016, the highest amount since 1991. (2) According to the Insurance Institute of Highway Safety, 45 percent of fatal bicycle crashes between 2008 and 2012 involved a vehicle hitting the bicyclist from behind or the side while traveling in the same direction. (3) Thirty-two states have a law requiring a motorist to provide at least 3 feet of space when passing a bicyclist.

Bike lanes next to on-street parallel parking.

For decades it has been the conventional wisdom that crashes involving bicyclists and opening car doors are rare. This belief is based on motor vehicle crash reports, but these reports generally exclude this crash type by definition. More complete sources show that dooring crashes are one of the most common causes of urban bicycle-motor vehicle collisions, accounting for 12%-27% of the total. This paper reviews all available studies of bicyclist position in bike lanes adjacent to on-street parking. With bike lanes meeting current minimum standards, almost all bicyclists were observed riding within range of opening doors. However, when an additional three or four feet is provided between the bike lane and parked cars, hardly any bicyclists are observed in the door zone. All of the design guides recently developed in North America for separated bike lanes include a buffer to account for the door zone when the bike lane is placed between on-street parallel parking and the curb. However, only the Ontario design guide has a similar requirement for standard bike lanes. The buffer requirement for standard bike lanes adjacent to on-street parking should be incorporated into all design guidance. When there is not room for this necessary buffer, an alternative is to place a shared lane marking in the center of the travel lane, which encourages bicyclists to ride outside the door zone. Increasing the number of bicyclists who ride outside of the door zone may require lowering speed limits and repealing laws that create a presumption that bicyclists must always keep to the right of the travel lane.

Evaluating the impact of Mobike on automobile-involved bicycle crashes at the road network level.

As a booming system, free-floating bicycle-sharing (denoted as Mobike) attracts a large number of users due to the convenient utilization procedure. However, it brings about a rapid increase of bicycle volume on roadways, resulting in safety problems especially on road segments shared by automobiles and bikes. This study aimed to evaluate impacts of Mobike on automobile-involved bicycle crashes on shared roadways at a macro level, the network level. Relation between traffic volumes and crashes was first established. Then, the travel mode choice before and after supplying Mobike in the market was analyzed, based on which the multi-class multi-modal user equilibrium (MMUE) models were formulated and solved. Two attributes of Mobike, supply quantity and fare, were investigated via various scenarios. Results suggested the Mobike attracted more walkers than auto-users in travel mode choices, which caused the volume increase of bicycles but few volume decline of automobiles and resulted in more crashes. The supply quantity of Mobike had a negative impact on safety, while the fare had a positive effect. The total supply of Mobike in the market should be regulated by governments to avoid over-supply and reduce bicycle crashes. The fares should be also regulated by including taxes and insurances, which can be used to build up more separated bicycle facilities and cover the Mobike accidents, respectively. The findings of this study provide useful information for governments and urban transportation managers to improve bicycle safety and regulate the Mobike market.

Applying the health action process approach to bicycle helmet use and evaluating a social marketing campaign.

BACKGROUND: Bicycle injuries are of concern in Canada. Since helmet use was mandated in 1996 in the province of British Columbia, Canada, use has increased and head injuries have decreased. Despite the law, many cyclists do not wear a helmet. Health action process approach (HAPA) model explains intention and behaviour with self-efficacy, risk perception, outcome expectancies and planning constructs. The present study examines the impact of a social marketing campaign on HAPA constructs in the context of bicycle helmet use. METHOD: A questionnaire was administered to identify factors determining helmet use. Intention to obey the law, and perceived risk of being caught if not obeying the law were included as additional constructs. Path analysis was used to extract the strongest influences on intention and behaviour. The social marketing campaign was evaluated through t-test comparisons after propensity score matching and generalised linear modelling (GLM) were applied to adjust for the same covariates. RESULTS: 400 cyclists aged 25-54 years completed the questionnaire. Self-efficacy and Intention were most predictive of intention to wear a helmet, which, moderated by planning, strongly predicted behaviour. Perceived risk and outcome expectancies had no significant impact on intention. GLM showed that exposure to the campaign was significantly associated with higher values in self-efficacy, intention and bicycle helmet use. CONCLUSION: Self-efficacy and planning are important points of action for promoting helmet use. Social marketing campaigns that remind people of appropriate preventive action have an impact on behaviour.

The changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists.

AIMS: To investigate the changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists. MATERIALS AND METHODS: Data on all non-spinal open fractures admitted to the Royal Infirmary of Edinburgh after a road traffic accident between 1988 and 2010 were collected and analysed to provide information about the changing epidemiology in different patient groups. Demographic information was collected on all patients with the severity of injury being analysed with the Injury Severity Score (ISS), Musculoskeletal Index (MSI) and the number of open fractures. The severity of the open fractures was analysed using the Gustilo classification. The 23-year study period was divided into four shorter periods and the results were compared. RESULTS: There were 696 patients treated in 23 years. Analysis showed that the incidence of RTA open fractures initially fell in both males and females and continued to fall in females during the 23 years. In males it levelled off about 2000. The age of the female patients also fell during the study period but it did not change in males. The only patient group to show an increased incidence of open fractures were cyclists. In vehicle occupants the incidence fell throughout the study period but it levelled off in pedestrians and motorcyclists. There was no difference in the severity of injury in any group during the study period. The most severe open fractures were those of the distal femur and femoral diaphysis although open tibial diaphyseal fractures were the most common fracture in all patient groups. CONCLUSIONS: Improved car design and road safety legislation has resulted in a reduction in the incidence of open fractures in vehicle occupants, pedestrians and motorcyclists. The most obvious group to have benefitted from this are older female pedestrians. The only group to show an increase in age during the study period were male motorcyclists.

Examination of adult and child bicyclist safety-relevant events using naturalistic bicycling methodology.

Among roadway users, bicyclists are considered vulnerable due to their high risk for injury when involved in a crash. Little is known about the circumstances leading to near crashes, crashes, and related injuries or how these vary by age and gender. The purpose of this study was to examine the rates and characteristics of safety-relevant events (crashes, near crashes, errors, and traffic violations) among adult and child bicyclists. Bicyclist trips were captured using Pedal Portal, a data acquisition and coding system which includes a GPS-enabled video camera and graphical user interface. A total of 179 safety-relevant events were manually coded from trip videos. Overall, child errors and traffic violations occurred at a rate of 1.9 per 100min of riding, compared to 6.3 for adults. However, children rode on the sidewalk 56.4% of the time, compared with 12.7% for adults. For both adults and children, the highest safety-relevant event rates occurred on paved roadways with no bicycle facilities present (Adults=8.6 and Children=7.2, per 100min of riding). Our study, the first naturalistic study to compare safety-relevant events among adults and children, indicates large variation in riding behavior and exposure between child and adult bicyclists. The majority of identified events were traffic violations and we were not able to code all risk-relevant data (e.g., subtle avoidance behaviors, failure to check for traffic, probability of collision). Future naturalistic cycling studies would benefit from enhanced instrumentation (e.g., additional camera views) and coding protocols able to fill these gaps.