Relative injury severity among vulnerable non-motorised road users: Comparative analysis of injury arising from bicycle-motor vehicle and bicycle-pedestrian collisions

With the expansion of bicycle usage and limited funding and/or space for segregated pedestrian and bicycle paths, there is a need for traffic, road design and local government engineers to decide if it is more appropriate for space to be shared between either cyclists and pedestrians, or between cars and cyclists, and what restrictions need to be applied in such circumstances. To provide knowledge to aid engineers and policy makers in making these decisions, this study explored death and morbidity data for the state of New South Wales, Australia to examine rates and severity of injury arising from collisions between pedestrians and cyclists, and between cyclists and motor vehicles (MVs).An analysis of the severity of hospitalised injuries was conducted using International Classification of Diseases, Version 10, Australian Modification (ICD-10-AM) diagnosis-based Injury Severity Score (ICISS) and the Disability Adjusted Life Year (DALY) was used to measure burden of injury arising from collisions resulting in death or hospitalisation. The greatest burden of injury in NSW, for the studied collision mechanisms, is for cyclists who are injured in collisions with motor vehicles. Collisions between cyclists and pedestrians also result in significant injuries. For all collision mechanisms, the odds of serious injury on admission are greater for the elderly than for those in other age groups. The significant burden of injury arising from collisions of cyclists and MVs needs to be addressed. However in the absence of appropriate controls, increasing the opportunity for conflict between cyclists and pedestrians (through an increase in shared spaces for these users) may shift the burden of injury from cyclists to pedestrians, in particular, older pedestrians.     

Pedestrian at-fault crashes on rural and urban roadways in Alabama

The research described in this paper explored the factors contributing to the injury severity resulting from pedestrian at-fault crashes in rural and urban locations in Alabama incorporating the effects of randomness across the observations. Given the occurrence of a crash, random parameter logit models of injury severity (with possible outcomes of major, minor, and possible or no injury) for rural and urban locations were estimated. The estimated models identified statistically significant factors influencing the pedestrian injury severities. The results clearly indicated that there are differences between the influences of a variety of variables on the injury severities resulting from urban versus rural pedestrian at-fault accidents. The results showed that some variables were significant only in one location (urban or rural) but not in the other location. Also, estimation findings showed that several parameters could be modeled as random parameters indicating their varying influences on the injury severity. Based on the results obtained, this paper discusses the effects of different variables on pedestrian injury severities and their possible explanations. From planning and policy perspective, the results of this study justify the need for location specific pedestrian safety research and location specific carefully tailored pedestrian safety campaigns.     

Exploring the impact of a dedicated streetcar right-of-way on pedestrian motor vehicle collisions: A quasi experimental design

Background and Objectives

The frequency of pedestrian collisions is strongly influenced by the built environment, including road width, street connectivity and public transit design. In 2010, 2159 pedestrian collisions were reported in the City of Toronto, Canada with 20 fatalities. Previous studies have reported that streetcars operating in mixed traffic pose safety risks to pedestrians; however, few studies evaluate the effects on pedestrian-motor vehicle collisions (PMVC). The objective of this study was to examine changes in the rate and spatial patterning of PMVC, pre to post right-of-way (ROW) installation of the St. Clair Avenue West streetcar in the City of Toronto, Canada.

Methods

A quasi-experimental design was used to evaluate changes in PMVC rate, following implementation of a streetcar ROW. Collision data were extracted from all police-reported PMVC, complied and verified by the City of Toronto, from January 1, 2000 to December 31, 2011. A zero-inflated Poisson regression analysis estimated the change in PMVC, pre to post ROW. Age and injury severity were also examined. Changes in the spatial pattern of collisions were examined by applying the G function to describe the proportion of collision events that shared a nearest neighbor distance less than or equal to a threshold distance.

Results

A total of 23,607 PMVC occurred on roadways during the study period; 441 occurring on St. Clair Ave, 153 during the period of analysis. There was a 48% decrease in the rate of collisions on St. Clair [Incidence rate ratio (IRR) = 0.52, 95% CI: 0.37–0.74], post ROW installation. There were also decreases noted for children (IRR = 0.13, 95% CI: 0.04–0.44), adults (IRR = 0.61, 95% CI: 0.38–0.97), and minor injuries (IRR = 0.56, 95% CI: 0.40–0.80). Spatial analyses indicated increased dispersion of collision events across each redeveloped route segment following the changes in ROW design.

Conclusions/Implications

Construction of a raised ROW operating on St. Clair Ave. was associated with a reduction in the rate of collisions. Differences in pre- and post collision spatial structure indicated changes in collision locations. Results from this study suggest that a streetcar ROW may be a safer alternative for pedestrians compared to a mixed traffic streetcar route and should be considered by city planners where appropriate to the street environment.     

The effects of area deprivation on the incidence of child and adult pedestrian casualties in England

This paper analyses child pedestrian casualties in England, focusing on the influence of socio-economic deprivation. It develops an area-based model of pedestrian casualties and presents estimates based on data for the English wards. The results detect an association between increased deprivation and higher numbers of pedestrian casualties across England. The deprivation effect is strong both for all child casualties and for children killed or seriously injured. Estimates for adult casualties also reveal a positive and significant association with increasing deprivation, but the magnitude of the effect is smaller than for children. The paper concludes by outlining some of the implications of the research.     

The influence of the infrastructure characteristics in urban road accidents occurrence

This paper summarizes the result of a study regarding the creation of tools that can be used in intervention methods in the planning and management of urban road networks in Portugal.     

Accounting for indirect land-use change in the life cycle assessment of biofuel supply chains

The expansion of land used for crop production causes variable direct and indirect greenhouse gas emissions, and other economic, social and environmental effects. We analyse the use of life cycle analysis (LCA) for estimating the carbon intensity of biofuel production from indirect land-use change (ILUC). Two approaches are critiqued: direct, attributional life cycle analysis and consequential life cycle analysis (CLCA). A proposed hybrid ‘combined model’ of the two approaches for ILUC analysis relies on first defining the system boundary of the resulting full LCA. Choices are then made as to the modelling methodology (economic equilibrium or cause–effect), data inputs, land area analysis, carbon stock accounting and uncertainty analysis to be included. We conclude that CLCA is applicable for estimating the historic emissions from ILUC, although improvements to the hybrid approach proposed, coupled with regular updating, are required, and uncertainly values must be adequately represented; however, the scope and the depth of the expansion of the system boundaries required for CLCA remain controversial. In addition, robust prediction, monitoring and accounting frameworks for the dynamic and highly uncertain nature of future crop yields and the effectiveness of policies to reduce deforestation and encourage afforestation remain elusive. Finally, establishing compatible and comparable accounting frameworks for ILUC between the USA, the European Union, South East Asia, Africa, Brazil and other major biofuel trading blocs is urgently needed if substantial distortions between these markets, which would reduce its application in policy outcomes, are to be avoided.     

Bayesian spatial joint modeling of traffic crashes on an urban road network

This study proposes a Bayesian spatial joint model of crash prediction including both road segments and intersections located in an urban road network, through which the spatial correlations between heterogeneous types of entities could be considered. A road network in Hillsborough, Florida, with crash, road, and traffic characteristics data for a three-year period was selected in order to compare the proposed joint model with three site-level crash prediction models, that is, the Poisson, negative binomial (NB), and conditional autoregressive (CAR) models. According to the results, the CAR and Joint models outperform the Poisson and NB models in terms of model fitting and predictive performance, which indicates the reasonableness of considering cross-entity spatial correlations. Although the goodness-of-fit and predictive performance of the CAR and Joint models are equivalent in this case study, spatial correlations between segments and the connected intersections are found to be more significant than those solely between segments or between intersections, which supports the employment of the Joint model as an alternative in road-network-level safety modeling.     

The influence of vehicle damage on injury severity of drivers in head-on motor vehicle crashes

Data from crashes investigated through the Crash Injury Research and Engineering Network (CIREN) Program were used to assess differences in injury patterns, severity, and sources for drivers, protected by safety belts and deploying steering wheel air bags, in head-on frontal impacts. We studied whether exterior vehicle damage with a different distribution (wide vs. narrow) across the front vehicle plane influenced injury characteristics. Drivers from both impact types were similar on the basis of demographic characteristics (except age), restraint use, and vehicle characteristics. There were significant differences in the type of object contacted and intrusion into the passenger compartment at the driver's seat location. The mean delta V (based on the kilometers per hour change in velocity during the impact) was similar for drivers in both (wide vs. narrow) impact types. There were no significant differences in injury patterns and sources except that drivers in wide impacts were almost 4 times more likely (odds ratio (OR)=3.81, 95% confidence limits (CL) 1.26, 11.5) to have an abbreviated injury scale (AIS) 3 serious or greater severity head injury. Adjusted odds ratios showed that drivers in wide impacts were less likely (OR=0.54, 95% CI 0.37, 0.79) to have severe injury (based on injury severity score (ISS)>25) when controlling for intrusion, vehicle body type, vehicle curb weight, age, proper safety belt use, and delta V. Drivers with intrusion into their position or who were driving a passenger vehicle were almost twice more likely to have severe injury, regardless of whether the frontal plane damage distribution was wide or narrow. Our study supports that the type of damage distribution across the frontal plane may be an important crash characteristic to consider when studying drivers injured in head-on motor vehicle crashes.     

Red light for red-light cameras?: A meta-analysis of the effects of red-light cameras on crashes

A meta-analysis has been conducted on the effects of red-light cameras (RLCs) on intersection crashes. The size and direction of results reported from studies included in the meta-analysis are strongly affected by study methodology. The studies that have controlled for most confounding factors yield the least favourable results. Based on these studies, installation of RLCs leads to an overall increase in the number of crashes by about 15%. Rear-end collisions increase by about 40% and right angle collisions, which are the target crashes for RLC, are reduced by about 10%. All effects are, however, non-significant. Meta-regression analysis shows that results are more favourable when there is a lack of control for regression to the mean (RTM). An interaction is found between control for RTM and control for those spillover effects that result from the tendency of RLCs to affect crash levels in nearby intersections without RLC. In studies controlling for RTM, additional control for spillover effects reduces the favourability of results still further. Studies controlling for both RTM and spillover effects tend also to control for more additional factors than other studies. It is likely that the results are affected by additional moderator variables, which could not be investigated in this meta-analysis. RLCs may reduce crashes under some conditions, but on the whole RLCs do not seem to be a successful safety measure.     

The influence of carrying a backpack on college student pedestrian safety

University students walk frequently, and individuals ages 18-22 have among the highest rates of pedestrian injury among any age group in the United States. These injuries are caused by a wide range of individual, interpersonal, and environmental factors, but one factor that has not been previously considered carefully is the influence of wearing a heavy backpack on pedestrian safety. Backpacks are known to slow walking speed and disrupt perception of one's environment, so it is reasonable to question whether they might also influence safe pedestrian behavior. Ninety-six college students engaged in 20 street-crossings within a virtual pedestrian environment. Half the crossings were completed while bearing a backpack weighing 12% of their body weight; the other half were completed without any burdens. Results suggest that participants walked more slowly, left less safe time to spare after crossing the virtual street, and experienced more frequent hits or close calls with traffic when crossing while carrying the backpack. They also missed fewer safe opportunities to cross while carrying the backpack. Our tests of several demographic characteristics, pedestrian behaviors, and backpack use, as covariates suggest the finding holds across all subsamples included in our study. Implications for pedestrian safety and future research are discussed.     

The influence of gait stance on pedestrian lower limb injury risk

The effect of pedestrian gait on lower limb kinematics and injuries has not been analyzed. The purpose of this paper was therefore to investigate the effect of pedestrian gait on kinematics and injury risk to the lower limbs using the Total Human Model for Safety adult male pedestrian model together with FE models of vehicle front structures. The modeling results indicate that the tibia and femur cortical bone von-Mises stress and the lateral knee bending angle of an adult pedestrian are strongly dependent on the gait stance when struck by both a sedan car and an SUV at 40 km/h. The gait analysis shows that generally the leg of an adult pedestrian has lower injury risk when the knee is flexed and linear regressions show high negative correlation between knee flexion angle during impact and knee lateral bending angle and also high negative correlation between lower leg axial rotation during impact and knee lateral bending angle. Furthermore, in some gait stances a self-contact between the legs occurs, and the peak bones stresses and knee shearing displacement in the leg are then increased. Assessment of pedestrian lower limb injury should take account of these gait stance effects.     

The influence of road curvature on fatal crashes in New Zealand

Bends in roads can cause crashes but a recent study in the UK found that areas with mostly curved roads had lower crash rates than areas with straighter roads. This present study aimed to replicate the previous research in a different country. Variations in the number of fatal road crashes occurring between 1996 and 2005 in 73 territorial local authorities across New Zealand were modelled against possible predictors. The predictors were traffic flow, population counts and characteristics, car use, socio-economic deprivation, climate, altitude and road characteristics including four measures of average road curvature. The best predictors of the number of fatal crashes on urban roads, rural state highways and other rural roads were traffic flow, speed limitation and socio-economic deprivation. Holding significant factors constant, there was no evidence that TLAs with the most curved roads had more crashes than elsewhere. Fatal crashes on urban roads were significantly and negatively related to two measures of road curvature: the ratio of road length to straight distance and the cumulative angle turned per kilometre. Weaker negative associations on rural state highways could have occurred by chance. These results offer limited support to the suggestion that frequently occurring road bends might be protective.     

Macroscopic spatial analysis of pedestrian and bicycle crashes

This study investigates the effect of spatial correlation using a Bayesian spatial framework to model pedestrian and bicycle crashes in Traffic Analysis Zones (TAZs). Aggregate models for pedestrian and bicycle crashes were estimated as a function of variables related to roadway characteristics, and various demographic and socio-economic factors. It was found that significant differences were present between the predictor sets for pedestrian and bicycle crashes. The Bayesian Poisson-lognormal model accounting for spatial correlation for pedestrian crashes in the TAZs of the study counties retained nine variables significantly different from zero at 95% Bayesian credible interval. These variables were – total roadway length with 35 mph posted speed limit, total number of intersections per TAZ, median household income, total number of dwelling units, log of population per square mile of a TAZ, percentage of households with non-retired workers but zero auto, percentage of households with non-retired workers and one auto, long term parking cost, and log of total number of employment in a TAZ. A separate distinct set of predictors were found for the bicycle crash model. In all cases the Bayesian models with spatial correlation performed better than the models that did not account for spatial correlation among TAZs. This finding implies that spatial correlation should be considered while modeling pedestrian and bicycle crashes at the aggregate or macro-level.     

Effect of repeal of the national maximum speed limit law on occurrence of crashes, injury crashes, and fatal crashes on Utah highways

Speed limits were increased in Utah and other States after repeal of the national maximum speed limit law (NMSL) in 1995. This study analyzed effects of the increased speed limit on Utah highways on crash rates, fatality crash rates, and injury crash rates. Annual (1992-1999) rates of crashes, fatality crashes, and injury crashes for the following highway categories were calculated: urban Interstate segments (current speed limit 60-65 miles per hour (mph)); rural Interstate segments (current speed limit 70-75 mph); 55 mph rural non-Interstate highway segments; and high-speed non-Interstate highways (current speed limit 60-65 mph). Data were analyzed using autoregressive integrative moving average intervention time series analysis techniques. There were significant increases in total crash rates on urban (60-65 mph) Interstate segments (confounded by extensive ongoing highway construction on these highways), and in fatal crash rates on high-speed (60-65 mph) rural non-Interstate segments. The following variables were unaffected: total, fatality, and injury crash rates on rural Interstate segments; fatality and injury crash rates on urban Interstate segments; total and injury crash rates on high-speed non-Interstate segments. These results show an adverse effect on crash occurrence for subsets of crash types and highways, but do not show a major overall effect of NMSL repeal and increased speed limit on crash occurrence on Utah highways.     

The effect of roundabout design features on cyclist accident rate

Roundabouts are known to result in fewer traffic accidents than traditional intersections. However, this is to a lesser degree true for bicycles than for vehicles. In this paper, we aimed at establishing statistical relationships through Poisson regression and logistic regression analyses between yearly rate of cyclist accidents on one hand and roundabout geometry, age and traffic volume (vehicles and cyclists) on the other. We related all roundabout cyclist accidents recorded by the hospital emergency department of the town of Odense, Denmark, through the years 1999-2003 (N=171) to various geometric features, age and traffic volume of all roundabouts on the Danish island of Funen (N=88). Cyclist and vehicle volumes turned out to be significant predictors in most of our models-the higher the volumes, the more accidents. Moreover, potential vehicle speed was a significant predictor, and so was age of the roundabout-older roundabouts related to more accidents and higher accident probability. Excluding 48 single cyclist accidents strengthened the relationship between accidents on one hand and vehicle and cyclist volume and potential vehicle speed on the other. This stresses the significance of speed and traffic volume for traffic accidents with more than one partner involved. The 48 single cyclist accidents were significantly related to the traffic volume of cyclists only. Due to our limited number of observations, the models should be regarded as indicative.     

Understanding the impact of High Speed Railway on urban innovation performance from the perspective of agglomeration externalities and network externalities

Transportation infrastructure and innovation play an important role in promoting regional economic growth. However, previous studies have mainly focused on the economic agglomeration by increased accessibility, but ignored the important on inter-city economic linkages and the network externalities it generated. Based on the externality perspective, this paper uses the propensity score matching model (PSM-DID) and spatial econometric model to analyze the heterogeneous impact of HSR opening on urban innovation performance and compare the differential effects of agglomeration externalities and network externalities on knowledge spillovers. The empirical results suggest the following: (1) The opening of HSR significantly improves urban innovation performance, but there is significant spatial heterogeneity. (2) The opening of HSR not only promotes the agglomeration of production factors to cities, but also strengthens inter-city economic connections, thus improving urban innovation performance through agglomeration externalities and network externalities. However, compared to agglomeration externalities, network externalities have a superior strength of impact on urban innovation performance. (3) From the dynamic effect perspective, the opening of HSR has a hysteresis effect on urban innovation of 2–3 years, and differences exist between cities.     

Studying the effect of weather conditions on daily crash counts using a discrete time-series model

In previous research, significant effects of weather conditions on car crashes have been found. However, most studies use monthly or yearly data and only few studies are available analyzing the impact of weather conditions on daily car crash counts. Furthermore, the studies that are available on a daily level do not explicitly model the data in a time-series context, hereby ignoring the temporal serial correlation that may be present in the data. In this paper, we introduce an integer autoregressive model for modelling count data with time interdependencies. The model is applied to daily car crash data, metereological data and traffic exposure data from the Netherlands aiming at examining the risk impact of weather conditions on the observed counts. The results show that several assumptions related to the effect of weather conditions on crash counts are found to be significant in the data and that if serial temporal correlation is not accounted for in the model, this may produce biased results.     

Economic development's effect on road transport-related mortality among different types of road users: a cross-sectional international study

The relationship between a country's stage of economic development and its motor vehicle crash (MVC) mortality rate is not defined for different road users. This paper presents a cross-sectional regression analysis of recent national mortality in 44 countries using death certificate data provided by the World Health Organization. For five types of road users, MVC mortality is expressed as deaths per 100,000 people and per 1000 motor vehicles. Economic development is measured as gross national income (GNI) per capita in U.S. dollars and as motor vehicles per 1000 people. Results showed overall MVC mortality peaked among low-income countries at about US$ 2000 GNI per capita and at about 100 motor vehicles per 1000 people. Overall mortality declined at higher national incomes up to about US$ 24,000. Most changes in MVC mortality associated with economic development were explained by changes in rates among nonmotorized travelers, especially pedestrians. Overall MVC rates were lowest when pedestrian exposure was low because there were few motor vehicles or few pedestrians, and were highest during a critical transition to motorized travel, when many pedestrians and other vulnerable road users vied for use of the roadways with many motor vehicles.