Pedestrian injuries due to collisions with bicycles in New York and California

Effectiveness of road safety interventions: An evidence and gap map

Background

Road Traffic injuries (RTI) are among the top ten leading causes of death in the world resulting in 1.35 million deaths every year, about 93% of which occur in low- and middle-income countries (LMICs). Despite several global resolutions to reduce traffic injuries, they have continued to grow in many countries. Many high-income countries have successfully reduced RTI by using a public health approach and implementing evidence-based interventions. As many LMICs develop their highway infrastructure, adopting a similar scientific approach towards road safety is crucial. The evidence also needs to be evaluated to assess external validity because measures that have worked in high-income countries may not translate equally well to other contexts. An evidence gap map for RTI is the first step towards understanding what evidence is available, from where, and the key gaps in knowledge.

Objectives

The objective of this evidence gap map (EGM) is to identify existing evidence from all effectiveness studies and systematic reviews related to road safety interventions. In addition, the EGM identifies gaps in evidence where new primary studies and systematic reviews could add value. This will help direct future research and discussions based on systematic evidence towards the approaches and interventions which are most effective in the road safety sector. This could enable the generation of evidence for informing policy at global, regional or national levels.

Search Methods

The EGM includes systematic reviews and impact evaluations assessing the effect of interventions for RTI reported in academic databases, organization websites, and grey literature sources. The studies were searched up to December 2019.

Selection Criteria

The interventions were divided into five broad categories: (a) human factors (e.g., enforcement or road user education), (b) road design, infrastructure and traffic control, (c) legal and institutional framework, (d) post-crash pre-hospital care, and (e) vehicle factors (except car design for occupant protection) and protective devices. Included studies reported two primary outcomes: fatal crashes and non-fatal injury crashes; and four intermediate outcomes: change in use of seat belts, change in use of helmets, change in speed, and change in alcohol/drug use. Studies were excluded if they did not report injury or fatality as one of the outcomes.

Data Collection and Analysis

The EGM is presented in the form of a matrix with two primary dimensions: interventions (rows) and outcomes (columns). Additional dimensions are country income groups, region, quality level for systematic reviews, type of study design used (e.g., case-control), type of road user studied (e.g., pedestrian, cyclists), age groups, and road type. The EGM is available online where the matrix of interventions and outcomes can be filtered by one or more dimensions. The webpage includes a bibliography of the selected studies and titles and abstracts available for preview. Quality appraisal for systematic reviews was conducted using a critical appraisal tool for systematic reviews, AMSTAR 2.

Main Results

The EGM identified 1859 studies of which 322 were systematic reviews, 7 were protocol studies and 1530 were impact evaluations. Some studies included more than one intervention, outcome, study method, or study region. The studies were distributed among intervention categories as: human factors (n = 771), road design, infrastructure and traffic control (n = 661), legal and institutional framework (n = 424), post-crash pre-hospital care (n = 118) and vehicle factors and protective devices (n = 111). Fatal crashes as outcomes were reported in 1414 records and non-fatal injury crashes in 1252 records. Among the four intermediate outcomes, speed was most commonly reported (n = 298) followed by alcohol (n = 206), use of seatbelts (n = 167), and use of helmets (n = 66). Ninety-six percent of the studies were reported from high-income countries (HIC), 4.5% from upper-middle-income countries, and only 1.4% from lower-middle and low-income countries. There were 25 systematic reviews of high quality, 4 of moderate quality, and 293 of low quality.

Authors' Conclusions

The EGM shows that the distribution of available road safety evidence is skewed across the world. A vast majority of the literature is from HICs. In contrast, only a small fraction of the literature reports on the many LMICs that are fast expanding their road infrastructure, experiencing rapid changes in traffic patterns, and witnessing growth in road injuries. This bias in literature explains why many interventions that are of high importance in the context of LMICs remain poorly studied. Besides, many interventions that have been tested only in HICs may not work equally effectively in LMICs. Another important finding was that a large majority of systematic reviews are of low quality. The scarcity of evidence on many important interventions and lack of good quality evidence-synthesis have significant implications for future road safety research and practice in LMICs. The EGM presented here will help identify priority areas for researchers, while directing practitioners and policy makers towards proven interventions.

Systematic literature review of 10 years of cyclist safety research

Cyclist safety is a research field that is gaining increasing interest and attention, but still offers questions and challenges open to the scientific community. The aim of this study was to provide an exhaustive review of scientific publications in the cyclist safety field. For this purpose, Bibliometrix-R tool was used to analyse 1066 documents retrieved from Web of Science (WoS) between 2012 and 2021. The study examined published sources and productive scholars by exposing their most influential contributions, presented institutions and countries most contributing to cyclist safety and explored countries open towards international collaborations. A keywords analysis provided the most frequent author keywords in cyclist safety shown in a word cloud with E-bike, behaviour, and crash severity representing the primary keywords. Furthermore, a thematic map of cyclist safety field drafted from the author's keywords was identified. The strategic diagram is divided in four quadrants and, according to both density and centrality, the themes can be classified as follows: 1) motor themes, characterized by high value of both centrality and density; 2) niche themes, defined by high density and low centrality; 3) emerging or declining themes, featured by low value of both centrality and density; and 4) basic themes, distinguished by high centrality and low density. The motor themes (i.e., the main topics in cyclist safety field) crash severity and bike network were further explored. The research findings will be useful to develop strategies for making bike a safer and more confident form of transport as well as to guide researchers towards the future scientific knowledge.

A computational study on the basis for a safe speed limit for bicycles on shared paths considering the severity of pedestrian head injuries in bicyclist-pedestrian collisions

Bicyclists and pedestrians are two large vulnerable groups of road users. Many cities have allowed cyclists to share space with pedestrians on footpaths and off-road paths to reduce conflict with motor vehicles. The risk of bicyclist-pedestrian accidents is also increasing accordingly. Therefore, there is a need to understand the factors that affect the risk of injury in such accidents, especially to pedestrians who are considered more vulnerable. This paper presents a detailed investigation of bicyclist-pedestrian collisions and possible injury outcomes. The study has considered five levels of collision speed ranging from 10 km/h to 30 km/h, three pedestrian profiles (adult, child, and elderly) differentiated by their weight and height, three bicycles with different masses, and five impact directions. The bicyclist-pedestrian collision simulations have been analyzed based on four metrics: throw distance, peak head velocity on impact with the ground, head injury criterion (HIC) value, and the probability of severe head injury. For each simulation, the throw distance and peak head velocity on impact with the ground are extracted. Following that, the HIC and the probability of severe head injury to pedestrians are computed. The results show a significant effect of collision speed (p < 0.05) on all four metrics. The analysis has been further extended to study the effect of height and weight profile, bicycle mass, and impact directions on bicyclist-pedestrian collisions. According to the results, the impact directions largely influence the outcome of bicycle-pedestrian collisions. In general, direct impacts on pedestrian body center have been found to yield higher HIC values and probability of severe head injury to pedestrians than off-center impacts. Also, video analysis of simulated collisions has suggested that the accident mechanism depends on weight and height profiles (correlated with different age groups) and impact directions. Finally, recommendations have been proposed based on the study, including a speed limit of not more than 12 km/h for bicyclists on narrow shared paths and footpaths where risks of collisions with pedestrians are high. The results and analysis presented could be helpful for developing legislation to minimize conflicts between bicyclists and pedestrians on shared paths and to reduce potential injury to pedestrians.

Do stop-signs improve the safety for all road users? A before-after study of stop-controlled intersections using video-based trajectories and surrogate measures of safety

Converting minor-approach-only stop (MAS) intersections to all-way-stop (AWS) intersections is a prevailing safety countermeasure in North American urban areas. Although the general population positively perceives the installation of stop-signs in residential areas, little research has investigated the impact of AWS on road safety and road user behaviour. This paper investigated the safety effectiveness of converting MAS to AWS intersections using an observational before and after approach and surrogate measures of safety. More specifically, the safety impacts of AWS conversion were investigated using multiple indicators, including vehicle speed measures, vehicle-pedestrian, vehicle-cyclist, vehicles-vehicle interactions as well as yielding rates before and after the treatment implementation. A multi-level regression approach was adopted to determine the effect of stop signs controlling for built environments, traffic exposure, and intersection geometry factors as well as site-specific unobserved heterogeneity. A unique sample of 31 intersections were used in this before-after study. From this sample, video data were collected before and after implementing AWS. In total, 245 h of video were automatically processed and corrected using a specialized computer vision software. More than 68,000 (37,668 before and 31,305 after AWS treatment) road user trajectories were obtained from 104 approaches. The results show that the conversion of MAS to AWS intersections significantly decreased vehicle speed and increased post-encroachment time. This work also shows that implementing AWS significantly increased the yielding rates from 45.7% to 76.7% in MAS conditions and reduced the average speed of motor-vehicles. Using multi-level regression model, it is estimated that when the intersection was converted from MAS to AWS, the minimum speed in the major approaches was reduced by 60.0%.

Pedestrian injuries in collisions with pedal cycles in the context of increased active travel: Trends in England, 2005-2015

INTRODUCTION

Increasing levels of active travel in the population brings many public health benefits, but may also change the risks of road injury for different road users. We examined changes in rates of pedestrian injuries resulting from collisions with pedal cycles and motor vehicles in England during 2005-2015, a period of increased cycling activity, and described the gender, age distribution and locations of pedestrians injured in collisions with pedal cycles and motor vehicles.

METHODS

Collisions data were obtained from police STATS19 datasets. We used two measures of cycle/motor vehicle use; miles per annum, and estimated average travel time, and assessed evidence for trends towards increase over time using Poisson regression analysis.

RESULTS

There were 3414 pedestrians injured in collisions with one or more pedal cycles in England during 2005-2015, 763 of whom were killed or seriously injured (KSI). This accounted for 1.3% of the total pedestrians KSI from all vehicles. Of those KSI in collisions with cycles, 62% were female; 42% over the age of 60; 26% were on the footway or verge and 24% were on a pedestrian crossing. There was a 6% (IRR 1.056; 95% CI 1.032-1.080, p < 0.001) annual increase in the pedestrian KSI rate per billion vehicle miles cycled in England over the time span. This increase was disproportionate to the increase in cycle use measured by vehicle miles or time spent cycling.

CONCLUSIONS

Increases in cycling were associated with disproportionate increases in pedestrian injuries in collisions with pedal cycles in England, although these collisions remain a very small proportion of all road injury. Increased active travel is essential for meeting a range of public health goals, but needs to be planned for with consideration for potential impact on pedestrians, particularly older citizens.

Modelling bus-pedestrian crash severity in the state of Victoria, Australia

Understanding the relationship between bus-pedestrian crash severity and factors contributing to such crashes is important. However, there exists a dearth of research on the factors affecting bus-pedestrian crash severity. This study aims to fulfil this gap by investigating the factors affecting the severity of pedestrian injuries. A data set of bus-pedestrian crashes in the State of Victoria, Australia was analysed over the period of 2006 - 2019. Through the results of association rule discovery method, the factors that increase the risk of pedestrian fatality are darkness, pedestrian walking on carriageway with traffic, intersections, high speed zone, old pedestrian, young bus driver and weekend holidays. Furthermore, co-occurrence of factors that increase the risk of a pedestrian fatality were extracted. To reduce the injuries of bus-pedestrian crashes, we recommend improving the light conditions, reducing the jaywalking behaviour of pedestrians, implementing speed bumps in high speed zones and installing pedestrian detection systems on buses.13 years of bus-pedestrian crashes in Victoria, Australia was analyzed.Association rules discovery was used for modeling pedestrian fatality.Darkness, pedestrian movement, zone speed and age effect the rate of fatality.Pattern of pedestrian fatality in collision with bus was extracted.

Recent trends and demographics of pedestrians injured in collisions with cyclists

INTRODUCTION

Despite extensive media coverage of pedestrians who are injured in collisions with cyclists, little systematic inquiry has been carried out on this topic. This study examines the incidence of pedestrian injuries due to collisions with cyclists in the United States and in New York State and New York City (NYC) from 2005 to 2018.

METHOD

The study rests on national data derived from the Nationwide Emergency Department Sample (NEDS) and state and local data gathered by the Statewide Planning and Research Cooperative System (SPARCS). A negative binomial regression analysis was performed on the state and local data to measure the simultaneous effects of demographic variables on the incidence of pedestrian injuries. The study also mapped the incidence of injuries in NYC neighborhoods.

RESULTS

Pedestrian injuries due to collisions with cyclists declined at both the national and state and local levels from 2005 to 2018. The decline was particularly pronounced among school-aged children. In NYC, the distribution of injuries was concentrated in certain neighborhoods.

CONCLUSIONS

Possible explanations for the decline in injuries include the change in the age composition of NYC's population, the greater level of physical inactivity among school-aged children, stricter enforcement of traffic laws, and, importantly, improvements in the cycling infrastructure. Practical Applications: Cycling as a mode of transportation is continuing to grow in popularity, particularly in large cities in the United States and Europe. With this upsurge in popularity, it is important to create a safe environment for all road users. Improvements in the cycling infrastructure (especially the installation of protected bike lanes) reduce hazards not only to cyclists but to pedestrians as well.

Bicycle helmets are highly protective against traumatic brain injury within a dense urban setting

BACKGROUND

New York City (NYC) has made significant roadway infrastructure improvements, initiated a bicycle share program, and enacted Vision Zero, an action plan to reduce traffic deaths and serious injuries. The objective of this study was to examine whether bicycle helmets offer a protective advantage against traumatic brain injury (TBI) within a contemporary dense urban setting with a commitment to road safety.

METHODS

A prospective observational study of injured bicyclists presenting to a Level I trauma centre was performed. All bicyclists arriving within 24 h of injury were included. Data were collected between February, 2012 and August, 2014 and included demographics, imaging studies (e.g. computed tomography (CT)), injury patterns, and outcomes including Glasgow Coma Scale (GCS) and Injury Severity Score.

RESULTS

Of 699 patients, 273 (39.1%) were wearing helmets at the time of injury. Helmeted bicyclists were more likely to have a GCS of 15 (96.3% [95% Confidence Interval (CI), 93.3-98.2] vs. 87.6 [95% CI, 84.1-90.6]) at presentation. Helmeted bicyclists underwent fewer head CTs (40.3% [95% CI, 34.4-46.4] vs. 52.8% [95% CI, 48.0-57.6]) and were less likely to sustain intracranial injury (6.3% [95% CI, 2.6-12.5] vs. 19.7% [14.7-25.6]), including skull fracture (0.9% [95% CI, 0.0-4.9] vs. 15.3% [95% CI, 10.8-20.7]) and subdural hematoma (0.0% [95% CI, 0.0-3.2] vs. 8.1% [95% CI, 4.9-12.5]). Helmeted bicyclists were significantly less likely to sustain significant TBI, i.e. Head AIS ≥3 (2.6% [95% CI: 0.7-4.5] vs.10.6% [7.6-12.5]). Four patients underwent craniotomy while three died; all were un-helmeted. A multivariable logistic regression model showed that helmeted bicyclists were 72% less likely to sustain TBI compared with un-helmeted bicyclists (Adjusted Odds Ratio 0.28, 95% CI 0.12-0.61).

CONCLUSIONS

Despite substantial road safety measures in NYC, the protective impact of simple bicycle helmets in the event of a crash remains significant. A re-assessment of helmet laws for urban bicyclists is advisable to most effectively translate Vision Zero from a political action plan to public safety reality.

[Risk factors for provoking collisions between cyclists and pedestrians in Spain, 1993-2011]

OBJECTIVE

To identify and quantify the factors depending on pedestrians, cyclists and the environment associated with the risk of causing a collision between a cyclist and a pedestrian in Spain from 1993 to 2011.

METHODS

STUDY DESIGN

retrospective case series.

POPULATION

1228 pedestrian-cyclist pairs involved in the same number of collisions in an urban area, only one of whom committed an infraction.

SOURCE

Register of Traffic Accidents with Victims, supported by the Spanish Traffic General Directorate.

VARIABLES

committing an infraction (yes/no), age, sex, helmet use (cyclist), hour, type of day, year, existence of sidewalks, place of the accident, and priority regulated.

ANALYSIS

logistic regression model to estimate the strength of the association between the pedestrian's responsibility and independent variables. The association with the cyclist's responsibility was assessed by reversing the value of the odds ratios obtained.

RESULTS

In both groups of users, the risk of causing a collision was higher in extreme ages. Female cyclists had a slightly higher risk than male cyclists, while the use of a helmet had a protective effect. The risk of the pedestrian causing an accident was higher in the absence of sidewalks. Cyclists more frequently provoked accidents in crosswalks.

CONCLUSION

We recommend the implementation of safety campaigns aimed at pedestrians and cyclists, with special attention paid to the youngest and older people. Interventions for correct road use would also be advisable.