Effects of electronic stability control: an update

OBJECTIVE: An earlier study reported that electronic stability control (ESC) in passenger vehicles reduced single-vehicle crash involvement risk by 41% and single-vehicle fatal crash involvement risk by 56%. The purpose of the present study was to update these effectiveness estimates using an additional year of crash data and a larger set of vehicle models. METHODS: The amount of data increased by half, allowing for separate effectiveness estimates for cars and sport utility vehicles (SUVs) and a more detailed examination of multiple-vehicle crash types. Crash involvement rates per registered vehicle were compared for otherwise identical vehicle models with and without ESC. RESULTS: Based on all police-reported crashes in 10 states during three years, ESC reduced single-vehicle crash involvement risk by approximately 41%. Effects were significantly higher for SUVs than for cars. ESC reduced single-vehicle crash involvement risk by 49% for SUVs and 33% for cars. Based on all fatal crashes in the United States during four years, ESC was found to have reduced single-vehicle fatal crash involvement risk by 56%. Again, effectiveness estimates were higher for SUVs than for cars--59% for SUVs and 53% for cars, but these differences were not statistically significant. Multiple-vehicle fatal crash involvement risk was reduced by 32%-37% for SUVs and 25% for cars. CONCLUSIONS: The present study confirms the results of the earlier study. There are significant reductions in single-vehicle crash rates when passenger vehicles are equipped with ESC. In addition, ESC leads to reductions in severe multiple-vehicle crashes.     

Teenage driver crash incidence and factors influencing crash injury by rurality

BackgroundPrevious research has identified teenage drivers as having an increased risk for motor-vehicle crash injury compared with older drivers, and rural roads as having increased crash severity compared with urban roads. Few studies have examined incidence and characteristics of teen driver-involved crashes on rural and urban roads.MethodsAll crashes involving a driver aged 10 through 18 were identified from the Iowa Department of Transportation crash data from 2002 through 2008. Rates of overall crashes and fatal or severe injury crashes were calculated for urban, suburban, rural, and remote rural areas. The distribution of driver and crash characteristics were compared between rural and urban crashes. Logistic regression was used to identify driver and crash characteristics associated with increased odds of fatal or severe injury among urban and rural crashes.ResultsFor younger teen drivers (age 10 through 15), overall crash rates were higher for more rural areas, although for older teen drivers (age 16 through 18) the overall crash rates were lower for rural areas. Rural teen crashes were nearly five times more likely to lead to a fatal or severe injury crash than urban teen crashes. Rural crashes were more likely to involve single vehicles, be late at night, involve a failure to yield the right-of-way and crossing the center divider.ConclusionsIntervention programs to increase safe teen driving in rural areas need to address specific risk factors associated with rural roadways.Impact on IndustryTeen crashes cause lost work time for teen workers as well as their parents. Industries such as safety, health care, and insurance have a vested interest in enhanced vehicle safety, and these efforts should address risks and injury differentials in urban and rural roadways.     

The effectiveness of electronic stability control in reducing real-world crashes: a literature review

OBJECTIVE: Electronic stability control (ESC) is designed to help drivers maintain heading control of their vehicles in high-speed or sudden maneuvers and on slippery roads. The wider proliferation of ESC across the vehicle fleet has allowed evaluation of its effects in real-world crashes in many countries, including Japan, Germany, Sweden, France, Great Britain, and the United States. This article provides a summary of the findings. METHODS: Studies that examined the real-world effectiveness of ESC were reviewed. Crash effects have been examined for different roadways, using differing analytic methods, different crash severities, and different make/model vehicles including both cars and SUVs. The review discusses the methodological differences and examines the findings according to vehicle type, crash type and severity, and road conditions. RESULTS: The overwhelming majority of studies find that ESC is highly effective in reducing single-vehicle crashes in cars and SUVs. Fatal single-vehicle crashes involving cars are reduced by about 30-50% and SUVs by 50-70%. Fatal rollover crashes are estimated to be about 70-90% lower with ESC regardless of vehicle type. A number of studies find improved effectiveness in reducing crashes when road conditions are slippery. There is little or no effect of ESC in all multi-vehicle crashes; however, there is a 17-38% reduction in more serious, fatal multi-vehicle crashes. CONCLUSIONS: Given the extraordinary benefits of ESC in preventing crashes, especially those with more serious outcomes, the implementation of ESC should be accelerated to cover the full range of passenger vehicles in both developed and developing markets.     

The effectiveness of electronic stability control (ESC) in reducing real life crashes and injuries

Electronic Stability Control (ESC) was introduced on the mass market in 1998. Since then, several studies showing the positive effects of ESC have been presented. OBJECTIVE: In this study, data from crashes occurring in Sweden during 1998 to 2004 were used to evaluate the effectiveness of ESC on real life crashes. The effectiveness was analyzed for different road conditions, and some accident types and injury levels. METHODS: The study used statistical analysis. To control for exposure, induced exposure methods were used, where ESC-sensitive to ESC-insensitive crashes and road conditions were matched in relation to cars equipped with and without ESC. Cars of similar or, in some cases, identical make and model were used to isolate the role of ESC. RESULTS: The study shows a positive and consistent effect of ESC overall and in circumstances where the road has low friction. The overall effectiveness on all injury crash types, except rear end crashes, was 16.7 +/- 9.3%, while for serious and fatal crashes; the effectiveness was 21.6 +/- 12.8%. The corresponding estimates for crashes with injured car occupants were 23.0 +/- 9.2% and 26.9 +/- 13.9%.For serious and fatal loss-of-control type crashes on wet roads the effectiveness was 56.2 +/- 23.5% and for roads covered with ice or snow the effectiveness was 49.2 +/- 30.2%. It was estimated that for Sweden, with a total of 500 vehicle related deaths annually, that 80-100 fatalities could be saved annually if all cars had ESC.CONCLUSIONS: ESC was found to reduce crashes with personal injuries, especially serious and fatal injuries. The effectiveness ranged from at least 13% for car occupants in all types of crashes with serious or fatal outcome to a minimum of 35% effectiveness for single/oncoming/overtaking serious and fatal crashes on wet or icy road surface. No difference in deformation pattern was found for cars with or without ESC.     

Characteristics of rear-end crashes involving passenger vehicles with automatic emergency braking

Abstract

Objectives: Automatic emergency braking (AEB) is a proven effective countermeasure for preventing front-to-rear crashes, but it has not yet fully lived up to its estimated potential. This study identified the types of rear-end crashes in which striking vehicles with AEB are overrepresented to determine whether the system is more effective in some situations than in others, so that additional opportunities for increasing AEB effectiveness might be explored.

Methods: Rear-end crash involvements were extracted from 23?U.S. states during 2009–2016 for striking passenger vehicles with and without AEB among models where the system was optional. Logistic regression was used to examine the odds that rear-end crashes with various characteristics involved a striking vehicle with AEB, controlling for driver and vehicle features.

Results: Striking vehicles were significantly more likely to have AEB in crashes where the striking vehicle was turning relative to when it was moving straight (odds ratio [OR]?=?2.35; 95% confidence interval [CI], 1.76, 3.13); when the struck vehicle was turning (OR = 1.66; 95% CI, 1.25, 2.21) or changing lanes (OR = 2.05; 95% CI, 1.13, 3.72) relative to when it was slowing or stopped; when the struck vehicle was not a passenger vehicle or was a special use vehicle relative to a car (OR = 1.61; 95% CI, 1.01, 2.55); on snowy or icy roads relative to dry roads (OR = 1.83; 95% CI, 1.16, 2.86); or on roads with speed limits of 70+ mph relative to those with 40 to 45?mph speed limits (OR = 1.49; 95% CI, 1.10, 2.03). Overall, 25.3% of crashes where the striking vehicle had AEB had at least one of these overrepresented characteristics, compared with 15.9% of strikes by vehicles without AEB.

Conclusions: The typical rear-end crash occurs when 2 passenger vehicles are proceeding in line, on a dry road, and at lower speeds. Because atypical crash circumstances are overrepresented among rear-end crashes by striking vehicles with AEB, it appears that the system is doing a better job of preventing the more typical crash scenario. Consumer information testing programs of AEB use a test configuration that models the typical rear-end crash type. Testing programs promoting good AEB performance in crash circumstances where vehicles with AEB are overrepresented could guide future development of AEB systems that perform well in these additional rear-end collision scenarios.     

Crash risk of ESC-fitted passenger cars

Objective: We examined both fatal and injury at-fault crashes of a population of passenger cars fitted with electronic stability control (ESC). Crash rates were calculated in relation to both registration years and mileage. Crash rates were also calculated for a non-ESC car population and crash rate ratios were calculated to compare the crash risk between ESC-fitted and non-ESC-fitted passenger cars.

Methods: Passenger car models with and without ESC were identified (ESC-equipped cars: 3,352,813 registration years; non-ESC-equipped: 5,839,946 registration years) and their vehicle information for the period 2009–2013, including mileage (ESC-equipped vehicles: 89.3 billion kilometers; non-ESC-equipped: 72.4 billion kilometers), was drawn from the national Vehicular and Driver Data Register.

The registry of Finnish road accident investigation teams was accessed and all fatal at-fault crashes among the cars in the study populations (ESC 97; non-ESC 377) for the period 2009–2013 were analyzed. The motor insurance database includes at-fault crashes leading to injuries and was utilized for analyses (ESC: N?=?8,827, non-ESC: N?=?21,437).

Crash rates and crash rate ratios were calculated to evaluate crash risk of both ESC-equipped and non-ESC-equipped passenger cars. Poisson regression was used to model crash involvement rate ratios both per registration year and per mileage for vehicles with ESC and without ESC, controlling for age and gender of the vehicle owner and vehicle mass.

Results: Passenger cars fitted with ESC showed lower crash rates than non-ESC-equipped cars in all crash types studied. In general, the difference in crash rates between ESC-equipped and non-ESC-equipped vehicles was greater when the crashes were compared to the mileage rather than registration years. The mileage-proportional crash rate of ESC-equipped cars was 64% (95% confidence interval, 61%; 67%) lower in run-off-road crashes resulting in injury and as much as 82% (65%; 91%) lower in fatal run-off-road crashes when suicides and disease attacks were not taken into account.

Conclusions: Our results show that modern passenger cars provide a significant crash risk reduction, which depends on both ESC and passive safety features introduced. Results also show that exposure evaluation in terms of registration years (or vehicle population) instead of true mileage can provide an overly pessimistic view of the crash risk.     

Injury Outcome in Crashes with Guardrail End Terminals

Objective: The goal of this study is to evaluate the crash performance of guardrail end terminals in real-world crashes. Guardrail end terminals are installed at the ends of guardrail systems to prevent the rail from spearing through the car in an end-on collision. Recently, there has been a great deal of controversy as to the safety of certain widely used end terminal designs, partly because there is surprisingly little real-world crash data for end terminals. Most existing studies of end terminal crashes used data from prior to the mid-1990s. Since then, there have been large improvements to vehicle crashworthiness and seat belt usage rates, as well as new roadside safety hardware compliant with National Cooperative Highway Research Program (NCHRP) Report 350, “Recommended Procedures for the Safety Performance Evaluation of Highway Features.” Additionally, most existing studies of injury in end terminal crashes do not account for factors such as the occurrence of rollover. This analysis uses more recent crash data that represent post-1990s vehicle fleet changes and account for a number of factors that may affect driver injury outcome and rollover occurrence.

Methods: Passenger vehicle crashes coded as involving guardrail end terminals were identified in the set of police-reported crashes in Michigan in 2011 and 2012. End terminal performance was expected to be a function of end terminal system design. State crash databases generally do not identify specific end terminal systems. In this study, the coded crash location was used to obtain photographs of the crash site prior to the crash from Google Street View. These site photographs were manually inspected to identify the particular end terminal system involved in the crash. Multiple logistic regression was used to test for significant differences in the odds of driver injury and rollover between different terminal types while accounting for other factors.

Results: A total of 1,001 end terminal crashes from the 2011–2012 Michigan State crash data were manually inspected to identify the terminal that had been struck. Four hundred fifty-one crashes were found to be suitable for analysis. Serious to fatal driver injury occurred in 3.8% of end terminal crashes, moderate to fatal driver injury occurred in 11.8%, and 72.3% involved property damage only. No significant difference in moderate to fatal driver injury odds was observed between NCHRP 350 compliant end terminals and noncompliant terminals. Car drivers showed odds of moderate to fatal injury 3.6 times greater than LTV drivers in end terminal crashes. Rollover occurrence was not significantly associated with end terminal type.

Conclusions: Car drivers have greater potential for injury in end terminal crashes than light truck/van/sport utility vehicle drivers. End terminal designs compliant with NCHRP 350 did not appear to carry different odds of moderate driver injury than noncompliant end terminals. The findings account for driver seat belt use, rollover occurrence, terminal orientation (leading/trailing), control loss, and the number of impact events. Rollover and nonuse of seat belts carried much larger increases in injury potential than end terminal type. Rollover did not appear to be associated with NCHRP 350 compliance.     

Analyses of rear-end crashes based on classification tree models

OBJECTIVE: Signalized intersections are accident-prone areas especially for rear-end crashes due to the fact that the diversity of the braking behaviors of drivers increases during the signal change. The objective of this article is to improve knowledge of the relationship between rear-end crashes occurring at signalized intersections and a series of potential traffic risk factors classified by driver characteristics, environments, and vehicle types. METHODS: Based on the 2001 Florida crash database, the classification tree method and Quasi-induced exposure concept were used to perform the statistical analysis. Two binary classification tree models were developed in this study. One was used for the crash comparison between rear-end and non-rear-end to identify those specific trends of the rear-end crashes. The other was constructed for the comparison between striking vehicles/drivers (at-fault) and struck vehicles/drivers (not-at-fault) to find more complex crash pattern associated with the traffic attributes of driver, vehicle, and environment. RESULTS: The modeling results showed that the rear-end crashes are over-presented in the higher speed limits (45-55 mph); the rear-end crash propensity for daytime is apparently larger than nighttime; and the reduction of braking capacity due to wet and slippery road surface conditions would definitely contribute to rear-end crashes, especially at intersections with higher speed limits. The tree model segmented drivers into four homogeneous age groups: < 21 years, 21-31 years, 32-75 years, and > 75 years. The youngest driver group shows the largest crash propensity; in the 21-31 age group, the male drivers are over-involved in rear-end crashes under adverse weather conditions and the 32-75 years drivers driving large size vehicles have a larger crash propensity compared to those driving passenger vehicles. CONCLUSIONS: Combined with the quasi-induced exposure concept, the classification tree method is a proper statistical tool for traffic-safety analysis to investigate crash propensity. Compared to the logistic regression models, tree models have advantages for handling continuous independent variables and easily explaining the complex interaction effect with more than two independent variables. This research recommended that at signalized intersections with higher speed limits, reducing the speed limit to 40 mph efficiently contribute to a lower accident rate. Drivers involved in alcohol use may increase not only rear-end crash risk but also the driver injury severity. Education and enforcement countermeasures should focus on the driver group younger than 21 years. Further studies are suggested to compare crash risk distributions of the driver age for other main crash types to seek corresponding traffic countermeasures.     

Relationships of frontal offset crash test results to real-world driver fatality rates

In a study of the relationship between Insurance Institute for Highway Safety frontal offset crash test ratings and real-world fatality rates, there was a clear trend for better-rated vehicles to have lower driver fatality risk, although the correlation was not uniform across all vehicle groups or statistically significant in all cases. For all types of crashes combined, fatality rates per registered vehicle were generally lower for vehicles rated good than for vehicles rated poor, but rates for acceptable and marginal vehicles were not always within this range. A more precise examination of fatality risk was accomplished by comparing driver outcomes in fatal two-vehicle crashes. When a rated vehicle collided with a nonrated vehicle, the fatality risk for the rated vehicle driver was highest for poorly rated vehicles, then progressively smaller for vehicles with marginal, acceptable, or good ratings. For two-vehicle crashes of similar vehicles rated good and poor, the odds of driver fatality was 34 percent lower for the good vehicle than for the poor vehicle, but this estimate was not statistically significant. Finally, in head-on crashes of rated vehicles, the estimated odds of driver fatality was approximately 74 percent lower for the good vehicle than for the poor vehicle, with confidence limits ranging from 28 to 91 percent.     

Antilock Brake Systems and Risk of Different Types of Crashes in Traffic

While antilock braking systems (ABS) have been convincingly demonstrated to enhance test track braking performance, their effect on crash risk in actual driving remains less clear. This paper examines how ABS influences crash risk using mainly two published studies which used police-reported crashes. The published findings are augmented by including new data and additional results. All the work is based on seven General Motors (GM) passenger vehicles having ABS as standard equipment for 1992 models but not available for 1991 models. The ratio of crashes under an adverse condition (say, when the pavement is wet) to under a normal condition (say, when the pavement is dry) is compared for ABS and non-ABS vehicles. After correcting for such factors as model year effects not linked to ABS, the following associations between ABS and crash risk were found by averaging data from the five states Texas, Missouri, North Carolina, Pennsylvania and Indiana (the errors are one standard error): a (10 ± 3)% relative lower crash risk on wet roads compared to the corresponding comparison on dry roads; a (22 ± 11)% lower risk of a pedestrian crash compared to the risk of a non-pedestrian crash; a (39 ± 16)% increase in rollover crash risk compared to the risk of a non-rollover crash. Data from the same Ave states were used to examine two-vehicle rear-end collisions. Using the assumption that side-impact crashes estimate exposure, it was found that for wet roads ABS reduces the risk of crashing into a lead vehicle by (32 ± 8)%, but increases the risk of being struck in the rear by (30 ± 14)%. The results from this study and from all available reported studies are summarized in tabular form.     

Effect of electronic stability control on automobile crash risk

Per vehicle crash involvement rates were compared for otherwise identical vehicle models with and without electronic stability control (ESC) systems. ESC was found to affect single-vehicle crashes to a greater extent than multiple-vehicle crashes, and crashes with fatal injuries to a greater extent than less severe crashes. Based on all police-reported crashes in 7 states over 2 years, ESC reduced single-vehicle crash involvement risk by approximately 41 percent (95 percent confidence limits 3348) and single-vehicle injury crash involvement risk by 41 percent (2752). This translates to an estimated 7 percent reduction in overall crash involvement risk (310) and a 9 percent reduction in overall injury crash involvement risk (314). Based on all fatal crashes in the United States over 3 years, ESC was found to have reduced single-vehicle fatal crash involvement risk by 56 percent (3968). This translates to an estimated 34 percent reduction in overall fatal crash involvement risk (2145).     

Comparison of mid-block and intersection-related left turn collisions

OBJECTIVES: To evaluate the factors that might influence an occupant's injury severity during a left turn movement. METHODS: We used the National Automotive Sampling System Crashworthiness Data System (1995-2005) to compare crash characteristics and injury outcome between intersection and midblock left turn collisions. RESULTS: A total of 7,396 collisions were evaluated. Traffic control devices were present in 82% of intersection and 10% of mid-block collisions. After adjustment for potential confounding variables, drivers' injury severity was not significantly associated with the crash location. However, front seat passengers in mid-block collisions had 72% higher odds of experiencing an injury with injury severity score > or =9 (odds ratio: 1.72, 95% confidence interval: 1.09-2.69). Our analysis did not show that drivers or passengers in larger vehicles, e.g., sport utility vehicles and mini-vans, were at lower risk of more severe injuries in comparison to the car occupants in sedans. CONCLUSION: We found that in comparison to intersection-related left turn collisions, mid-block crashes are associated with more severe injuries for front seat passengers. Furthermore, size of the turning vehicle was not significantly associated with injury severity for drivers or front seat passengers.     

Responsibility of drivers, by age and gender, for motor-vehicle crash deaths

Problem: Motor-vehicle crash rate comparisons by age and gender usually are based on the extent to which drivers in a particular age/gender category are themselves injured or involved in crashes (e.g., the number of 20-year-old females in crashes). Basing comparisons instead on the extent to which drivers in various age/gender groups are responsible for deaths (including themselves) in their crashes is more revealing of their overall contribution to the problem. Methods: Data from the Fatality Analysis Reporting System (FARS, 1996–2000) were used in the analysis, which was based on crashes that involved one or two vehicles only. Drivers in fatal single-vehicle crashes were assumed to have responsibility for the crash. In fatal two-vehicle crashes, driver operator errors reported by police were used to assign crash responsibility. Results: When all crashes were considered, both the youngest and oldest drivers were most likely to be responsible for deaths in their crashes. In two-vehicle crashes, the oldest drivers were more likely than young drivers to be responsible. Young males were more likely than young females to be responsible for crash deaths, whereas females in their 50s and older were more likely than same-age males to be responsible. In terms of responsibility for deaths per licensed driver, young drivers, especially males, had the highest rates because of their high involvement rates and high responsibility rates. The majority of deaths for which young drivers were responsible occurred to people other than themselves, especially passengers in their vehicles, whereas the bulk of the deaths for which older drivers were responsible were their own. Discussion: The results highlight the contribution of young drivers to the motor-vehicle crash problem, the need for measures such as passenger restrictions in graduated licensing systems, and the need for vehicle modifications to better protect older occupants.     

Analysis of risk factors affecting driver injury and crash injury with drivers under the influence of alcohol (DUI) and non-DUI

Objective: The objective of this research was to study risk factors that significantly influence the severity of crashes for drivers both under and not under the influence of alcohol.

Methods: Ordinal logistic regression was applied to analyze a crash data set involving drivers under and not under the influence of alcohol in China from January 2011 to December 2014.

Results: Four risk factors were found to be significantly associated with the severity of driver injury, including crash partner and intersection type. Age group was found to be significantly associated with the severity of crashes involving drivers under the influence of alcohol. Crash partner, intersection type, lighting conditions, gender, and time of day were found to be significantly associated with severe driver injuries, the last of which was also significantly associated with severe crashes involving drivers not under the influence of alcohol.

Conclusions: This study found that pedestrian involvement decreases the odds of severe driver injury when a driver is under the influence of alcohol, with a relative risk of 0.05 compared to the vehicle-to-vehicle group. The odds of severe driver injury at T-intersections were higher than those for traveling along straight roads. Age was shown to be an important factor, with drivers 50–60 years of age having higher odds of being involved in severe crashes compared to 20- to 30-year-olds when the driver was under the influence of alcohol.

When the driver was not under the influence of alcohol, drivers suffered more severe injuries between midnight and early morning compared to early nighttime. The vehicle-to-motorcycle and vehicle-to-pedestrian groups experienced less severe driver injuries, and vehicle collisions with fixed objects exhibited higher odds of severe driver injury than did vehicle-to-vehicle impacts. The odds of severe driver injury at cross intersections were 0.29 compared to travel along straight roads. The odds of severe driver injury when street lighting was not available at night were 3.20 compared to daylight. The study indicated that female drivers are more likely to experience severe injury than male drivers when not under the influence of alcohol. Crashes between midnight and early morning exhibited higher odds of severe injury compared to those occurring at other times of day.

The identification of risk factors and a discussion on the odds ratio between levels of the impact of the driver injury and crash severity may benefit road safety stakeholders when developing initiatives to reduce the severity of crashes.     

Driver mortality in frontal crashes: comparison of newer and older airbag designs

In 1997, the National Highway Traffic Safety Administration amended its requirements for frontal crash performance under Federal Motor Vehicle Safety Standard 208 to temporarily allow 30 mi/h (48 km/h) sled tests with unbelted dummies as an alternative to 30 mi/h head-on rigid-barrier vehicle tests. This change permitted automakers to reduce airbag inflation forces so that they would be less likely to injure occupants who are close to airbags when they first deploy. Most vehicle models were sled-certified starting in model year 1998. Airbag-related deaths have decreased since 1997; however, controversy persists about whether reduced inflation forces might be decreasing protection for some occupants in high-severity frontal crashes. To examine the effects of the regulatory changes, this study computed rate ratios (RR) and 95% confidence intervals (95% CI) for passenger vehicle driver deaths per vehicle registration during 2000-2002 at principal impact points of 12 o'clock for 1998-99 model year vehicles relative to 1997 models. Passenger vehicles included in the study had both driver and passenger front airbags, had the same essential designs during the 1997-1999 model years, and had been sled-certified for drivers throughout model years 1998 and 1999. An adjustment was made for the higher annual mileage of newer vehicles. Findings were that the effect of the regulatory change varied by vehicle type. For cars, sport utility vehicles, and minivans combined, there was an 11 percent decrease in fatality risk in frontal crashes after changing to sled certification (RR = 0.89; 95% CI = 0.82-0.96). Among pickups, however, estimated frontal fatality risk increased 35 percent (RR = 1.35; 95% CI = 1.12-1.62). For a broad range of frontal crashes (11, 12, and 1 o'clock combined), the results indicated a modest net benefit of the regulatory change across all vehicle types and driver characteristics. However, the contrary finding for pickups needs to be researched further.     

Prediction of responsibility for drivers and riders involved in injury road crashes

Introduction: Responsibility analysis allows the evaluation of crash risk factors from crash data only, but requires a reliable responsibility assessment. The aim of the present study is to predict expert responsibility attribution (considered as a gold-standard) from explanatory variables available in crash data routinely recorded by the police, according to a data-driven process with explicit rules. Method: Driver responsibility was assessed by experts using all information contained in police reports for a sample of about 5000 injury crashes that occurred in France in 2011. Three statistical methods were used to predict expert responsibility attribution: logistic regression with L1 penalty, random forests, and boosting. Potential predictors of expert attribution referred to inappropriate driver actions and to external conditions at the time of the crash. Logistic regression was chosen to construct a score to assess responsibility for drivers and riders in crashes involving one or more motor vehicles, or involving a cyclist or pedestrian. Results: Cross-validation showed that our tool can predict expert responsibility assessments on new data sets. In addition, responsibility analyses performed using either the expert responsibility or our predicted responsibility return similar odds ratios. Our scoring process can then be used to reliably assess responsibility based on national police report databases, provided that they include the information needed to construct the score.     

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.     

Effects of lane departure warning on police-reported crash rates

ObjectiveTo evaluate the effects of lane departure warning (LDW) on single-vehicle, sideswipe, and head-on crashes.MethodPolice-reported data for the relevant crash types were obtained from 25 U.S. states for the years 2009–2015. Observed counts of crashes with fatalities, injuries, and of all severities for vehicles with LDW were compared with expected counts based on crash involvement rates for the same passenger vehicles without LDW, with exposure by vehicle series, model year, and lighting system standardized between groups. For relevant crashes of all severities and those with injuries, Poisson regression was used to estimate the benefits of LDW while also controlling for demographic variables; fatal crashes were too infrequent to be modeled.ResultsWithout accounting for driver demographics, vehicles with LDW had significantly lower involvement rates in crashes of all severities (18%), in those with injuries (24%), and in those with fatalities (86%). Adding controls for driver demographics in the Poisson regression reduced the estimated benefit of LDW only modestly in crashes of all severities (11%, p < 0.05) and in crashes with injuries (21%, p < 0.07).ConclusionsLane departure warning is preventing the crash types it is designed to address, even after controlling for driver demographics. Results suggest that thousands of lives each year could be saved if every passenger vehicle in the United States were equipped with a lane departure warning system that performed like the study systems.Practical applicationsPurchase of LDW should be encouraged, and, because drivers do not always keep the systems turned on, future efforts should focus on designing systems to encourage greater use and educating consumers about the benefits of using the systems.     

Data mining approach to model bus crash severity in Australia

Introduction: Buses are different vehicles in terms of dimensions, maneuverability, and driver's vision. Although bus traveling is a safe mode to travel, the number of annual bus crashes cannot be neglected. Moreover, limited studies have been conducted on the bus involved in fatal crashes. Therefore, identification of the contributing factors in the bus involved fatal crashes can reduce the risk of fatality. Method: Data set of bus involved crashes in the State of Victoria, Australia was analyzed over the period of 2006–2019. Clustering of crash data was accomplished by dividing them into homogeneous categories, and by implementing association rules discovery on the clusters, the factors affecting fatality in bus involved crashes were extracted. Results: Clustering results show bus crashes with all vehicles except motor vehicles and weekend crashes have a high rate of fatality. According to the association rule discovery findings, the factors that increase the risk of bus crashes with non-motor vehicles are: old bus driver, collision with pedestrians at signalized intersections, and the presence of vulnerable road users. Likewise, factors that increase the risk of fatality in bus involved crashes on weekends are: darkness of roads in high-speed zones, pedestrian presence at highways, bus crashes with passenger car by a female bus driver, and the occurrence of multi-vehicle crashes in high-speed zones. Practical Applications: The study provides a sequential pattern of factors, named rules that lead to fatality in bus involved crashes. By eliminating or improving one or all of the factors involved in rules, fatal bus crashes may be prevented. The recommendations to reduce fatality in bus crashes are: observing safe distances with the buses, using road safety campaigns to reduce pedestrians’ distracted behavior, improving the lighting conditions, implementing speed bumps and rumble strips in high-speed zones, installing pedestrian detection systems on buses and setting special bus lanes in crowded areas.