Single-vehicle Collisions Research Articles

Analyzing temporal trends of the factors that increase the risk of rollover in single-vehicle collisions

ABSTRACTThis article investigates the temporal stability of the factors that increase the risk of rollover in single-vehicle collisions by utilizing logistic regression modeling to analyze annual records of all single-vehicle collisions that occurred in North Carolina from January 1, 2004 to December 31, 2013. A separate model was developed for each analysis year, and all the models were compared together to identify the most temporally stable factors. The factors that were found to consistently increase the risk of rollover are vehicle age, exceeding the speed limit, rural highways, curved highways, drivers younger than the age of 21 years, drivers influenced by alcohol, illicit drugs, fatigue, or other medical conditions, and when the light-duty vehicle involved in the collision is not a passenger car. Conversely, three factors were found to have no temporally stable effect on the risk of rollover in single-vehicle collisions. Those three factors are undivided highways, driver gender, and adverse environmental conditions. To further demonstrate the scientific contributions of this research, an overall model is also developed for the entire overall analysis period so that a comparison may be made between the limited insights provided by the overall model and the in-depth insights provided by studying the temporal stability through analyzing the annual models developed.

Evaluation of Roundabout-Related Single-Vehicle Crashes

Roundabouts reduce fatal and injury crashes at intersections when converted from other intersection control types. In Wisconsin, roundabouts have been linked to a 38% decrease in fatal and injury crashes. Part of this reduction can be attributed to crash types that result in the mitigation of more serious injuries. However, the reduction comes at a cost because other crash types, such as single-vehicle collisions, may increase. Six years of crash data on 53 roundabouts in Wisconsin were examined for crash causes and geometric characteristics that affected single-vehicle crashes. Weather and impaired driving, particularly by younger drivers, were primary causes for more than half of all single-vehicle crashes at the study roundabouts. Younger drivers (18 to 24 years of age) were involved in a significantly higher proportion of single-vehicle crashes than the total proportion of licensed drivers in that age group. Younger drivers were involved in approximately one-third of all crashes that involved impaired driving and in two-thirds of all speed-related single-vehicle crashes. A negative binomial model was constructed to estimate run-off-road crashes at approaches. It was found that roundabouts with higher approach speeds and higher traffic volumes experienced more run-off-road crashes. Landscaped central islands experienced significantly lower frequencies of run-off-road crashes.

Investigating temporal trends in the explanatory variables related to the severity of drivers' injuries in single-vehicle collisions

Abstract This study identifies and quantifies the effects of different explanatory variables that increase the severity of drivers' injuries related to single-vehicle collisions involving light-duty vehicles. The research is based on utilizing logistic regression to analyze records of all traffic collisions that occurred in North Carolina for the years from 2007 to 2013. The study also investigates temporal stability of the identified explanatory variables throughout the analysis period. The identified explanatory variables include those related to the roadway, vehicle, driver, and environmental conditions. The explanatory variables related to the roadway include whether the roadway is divided or undivided, and whether it is in an urban or rural area. The explanatory variables related to the vehicle include vehicle's age, travel speed, and the type of the light-duty vehicle. The explanatory variables related to the driver include driver's age, gender, influence by alcohol or illicit drugs, and the use of seatbelt. The explanatory variables related to the environmental conditions include weather, lighting, and road surface conditions. Three of the investigated explanatory variables were found to be temporally unstable with significantly varying effects on the severity of drivers' injuries. Those temporally unstable variables include the travel speed, the type of the light-duty vehicle, and the age of the driver. All other investigated variables were found to be consistently significant throughout the analysis period. The findings of this research have the potential to help decision makers develop policies and countermeasures that reduce the severity of drivers' injuries by focusing on explanatory variables that consistently exhibit significant effects on the severity of drivers' injuries. The findings of this research also provide quantitative measures that may be used to determine the feasibility of implementing those countermeasures in reducing the severity of drivers' injuries related to single-vehicle collisions. Recommendations for future research are also provided.

Contributing factors and severity of serious single-passenger vehicle collisions in Beijing

ABSTRACTSingle-vehicle collision is a typical traffic collision, which usually causes heavy casualties and property losses. This study uses crash data during the last five years to obtain the characteristics of injury severity and contributing factors, and further provides some important insights for crash prevention and vehicle safety. Based on the investigation and in-depth data analysis of traffic collisions, 100 serious single-passenger vehicle collisions in Beijing, China, from 2009 to 2013 are collected. Main characteristics of occupant, vehicle, fixed objects, road, environment and their correlations with severity are analysed, respectively. The results demonstrate that time of occurrence, type of date, number of occupants and speed of vehicles are the significant factors related to the severity. And for the total crashes, chi-square test reveals that night time travelling, common weekday, single occupant in vehicle and over 80 km/h vehicle speed are significant related to nonfatal/fatal crashes. A logic regression model shows that driving solo and impacting trees increased the crash severity. Further, this paper discusses the main causation and related safety countermeasures on the serious single-vehicle collisions.

Epidemiology of law enforcement vehicle collisions in the US and California

Purpose – Concerns about the risk of traffic collision injury to both police officers and bystanders are increasing as the use of in-vehicle technologies becoming widespread among agencies. This study used national and California data to characterize traffic collisions in which a police vehicle was involved. The paper aims to discuss these issues. Design/methodology/approach – The authors used a California traffic collision database to retrospectively identify collisions that involved police vehicles for years 2007-2010. The authors summarized collision characteristics with descriptive methods and used log-binomial regression to estimate associations between personal and collision characteristics with officer culpability. Findings – The authors identified 5,233 traffic collisions in California. In total, 10 percent of law enforcement vehicles were motorcycles. In all, 9 percent of cruisers struck a pedestrian or bicyclist, compared with only 2 percent of motorcycles. Compared with officers aged 50 or older, officers in younger age categories were progressively much more likely to have been culpable. Motorcycle officers were 33 percent less likely to be culpable for their collision involvements. Approximately 100 fatal collisions involving a law enforcement vehicle occur each year in the USA. Originality/value – The findings from this study indicate that approximately 1,300 injury-producing traffic collisions occur each year in California that involve a law enforcement vehicle. The authors found that younger age, female sex, cruiser operation, traveling unbelted, and single-vehicle collision involvement were positively associated with officer culpability. Officer race and community population were not significantly associated with culpability. The occurrence of fatal collisions in the USA was stable over a 12-year period.

Factors associated with single-vehicle and multi-vehicle road traffic collision injuries in Ireland

Generalised linear regression models were used to identify factors associated with fatal/serious road traffic collision injuries for single- and multi-vehicle collisions. Single-vehicle collisions and multi-vehicle collisions occurring during the hours of darkness or on a wet road surface had reduced likelihood of a fatal/serious injury. Single-vehicle ‘driver with passengers’ collisions occurring at junctions or on a hill/gradient were less likely to result in a fatal/serious injury. Multi-vehicle rear-end/angle collisions had reduced likelihood of a fatal/serious injury. Single-vehicle ‘driver only’ collisions and multi-vehicle collisions occurring on a public/bank holiday or on a hill/gradient were more likely to result in a fatal/serious injury. Single-vehicle collisions involving male drivers had increased likelihood of a fatal/serious injury and single-vehicle ‘driver with passengers’ collisions involving drivers under the age of 25 years also had increased likelihood of a fatal/serious injury. Findings can enlighten decision-makers to circumstances leading to fatal/serious injuries.

Work zones versus nonwork zones: Risk factors leading to rear-end and sideswipe collisions

ABSTRACTTens of thousands of vehicular collisions occur annually in work zones with nearly double the fatality risk as compared to all collisions (work zone and nonwork zone). Due to this increase in risk, this study's objective is to investigate the possible causes of work zone collisions. After reviewing previous studies, the authors examined behavioral, environmental, and roadway geometric factors to understand their influence on fatal collision type for work zones and nonwork zones. Data from the National Highway Traffic Safety Administration Fatality Analysis Reporting System database was used for years 2010 to 2012. To analyze the data, negative binomial regression and multinomial logit models were utilized. A binary probit model directly compares work zone and nonwork zone data. Results demonstrate that rear-end and sideswipe collisions are more likely to cause fatalities in work zones compared to nonwork zones. Clear conditions, daylight, and straight roads increase the likelihood of these two collision types when compared to other types such as single-vehicle collisions. These findings suggest that Intelligent Transportation Systems countermeasures (speed harmonization, vehicle-to-vehicle communications) should be investigated to encourage safer car-following and lane-changing behaviors rather than to mitigate work zone–related infrastructure challenges.

Effects of Pavement Surface Conditions on Traffic Crash Severity

AbstractImproving road safety through proper pavement maintenance is one of the goals of pavement management. Many studies have found that pavement conditions significantly influence traffic safety. Although several studies have explored the relationship between pavement conditions and crash occurrence, the effect of poor pavement conditions on crash severity levels has not been investigated, especially by using a discrete model that can handle ordered data. This paper focuses on the development of the relationship between poor pavement conditions and crash severity levels using a series of Bayesian ordered logistic models for low/medium/high speed roads and single/multiple collision cases. The Bayesian ordered logistic regression models indicated that the poor pavement condition decreases the severity of single-vehicle collisions on low-speed roads whereas it increases their severity on high-speed roads. On the other hand, the poor pavement condition increases the severity of multiple-vehicle crashes on ...

Identifying Crash Patterns on Roundabouts

Objectives: Roundabouts are a type of circular intersection control generally associated with a favorable influence on traffic safety. International studies of intersections converted to roundabouts indicate a strong reduction in injury crashes, particularly for crashes with fatal or serious injuries. Nevertheless, some crashes still occur at roundabouts. The present study aims to improve the understanding of roundabout safety by identifying crash types, locations, and factors that are associated with roundabout crashes.Methods: An analysis of 399 crashes on 28 roundabouts in Flanders, Belgium, was carried out based on detailed crash descriptions; that is, crash data and collision diagrams. The crashes are sampled from police-reported crashes at roundabouts in the region of Flanders, Belgium. Collision diagrams of the registered crashes were used to distinguish 8 different crash types. The roundabout itself is divided into 11 detailed and different typical segments, according to previously established knowledge on the occurrence of crashes at roundabouts. The 8 roundabout crash types are examined by injury severity, crash location within the roundabout, type of roundabout, type of cycle facility, and type of involved road user.Results: Four dominant crash types are identified: rear-end crashes, collisions with vulnerable road users, entering–circulating crashes, and single-vehicle collisions with the central island. Crashes with vulnerable road users and collisions with the central island are characterized by significantly higher proportions of injury crashes. About 80% of the crashes occurred on the entry lanes and the circulatory road (segments 1–4). Road users who are the most at risk to be involved in serious injury crashes at roundabouts are cyclists and moped riders.Conclusions: The main goal of this study was to identify and analyze dominant crash types at roundabouts by taking into account detailed information on the crash location. Some connections between certain roundabout crash types, their crash location, and roundabout design characteristics have been found.

Potential Occupant Injury Reduction in the U.S. Vehicle Fleet for Lane Departure Warning–Equipped Vehicles in Single-Vehicle Crashes

Objective: Single-vehicle collisions involve only 10 percent of all occupants in crashes in the United States, yet these same crashes account for 31 percent of all fatalities. Along with other vehicle safety advancements, lane departure warning (LDW) systems are being introduced to mitigate the harmful effects of single-vehicle collisions. The objective of this study is to quantify the number of crashes and seriously injured drivers that could have been prevented in the United States in 2012 had all vehicles been equipped with LDW.Methods: In order to estimate the potential injury reduction benefits of LDW in the vehicle fleet, a comprehensive crash and injury simulation model was developed. The model's basis was 481 single-vehicle collisions extracted from the NASS-CDS for year 2012. Each crash was simulated in 2 conditions: (1) as it occurred and (2) as if the driver had an LDW system. By comparing the simulated vehicle's off-road trajectory before and after LDW, the reduction in the probability of a crash was determined. The probability of a seriously injured occupant (Maximum Abbreviated Injury Score [MAIS] 3+) given a crash was computed using injury risk curves with departure velocity and seat belt use as predictors. Each crash was simulated between 18 and 216 times to account for variable driver reaction, road, and vehicle conditions. Finally, the probability of a crash and seriously injured driver was summed over all simulations to determine the benefit of LDW.Results and Conclusions: A majority of roads where departure crashes occurred had 2 lanes and were undivided. As a result, 58 percent of crashes had no shoulder. LDW will not be as effective on roads with no shoulder as on roads with large shoulders. LDW could potentially prevent 28.9 percent of all road departure crashes caused by the driver drifting out of his or her lane, resulting in a 24.3 percent reduction in the number of seriously injured drivers.The results of this study show that LDW, if widely adopted, could significantly mitigate a harmful crash type. Larger shoulder width and the presence of lane markings, determined by manual examination of scene photographs, increased the effectiveness of LDW. This result suggests that highway systems should be modified to maximize LDW effectiveness by expanding shoulders and regularly painting lane lines.

The Protective Effect of Roadside Barriers for Motorcyclists

Objective: Roadside barriers are often deployed between road users and fixed hazards to protect users from injury. However, the United States and Australian Roadside Design Guides do not consider motorcyclists in the risk-based decision process for the deployment of a barrier, because the severity indices for barriers and fixed hazards were developed for passenger vehicles. The aim of the present article is to quantify the protective effect of barriers with regards to motorcyclist injury and to thereby inform the Roadside Design Guides as to the relative severity of roadside hazards and infrastructure for motorcyclists. Method: A retrospective case series study, using linked police-reported road crash and hospital admission data in New South Wales, Australia, from 2001 to 2009 was performed. Crude and adjusted relative risks of motorcyclist serious injury were determined for various fixed objects compared to barriers, using serious injury rates and multiple variable logistic regression. Calculated relative risks compared with guardrail for motorcyclists were compared with those determined from the United States and Australian Roadside Design Guides for passenger vehicle occupants. Results: The study identified 1364 motorcyclists injured as a result of single-vehicle collisions with roadside barriers, trees, utility poles, and other fixed roadside infrastructure. Trees, posts, and utility poles were shown to provide significantly higher risks of serious injury to motorcyclists compared to barriers. This was also found to be true for serious injuries to particular body regions, such as the head, spine, and torso. The results for motorcyclists were in reasonable agreement with those derived from severity indices in the United States and Australian Roadside Design Guides for passenger vehicle occupants. Conclusions: Roadside barriers provide a significant reduction in the risk of serious injury to motorcyclists compared to various roadside hazards. The provisions in the United States and Australian Roadside Design Guides for passenger vehicle occupants are generally applicable to motorcyclists and support the prior and ongoing use of such guides for designing roadsides that reduce the risk of injury to motorcyclists. However, a more realistic estimation might be derived by increasing the severity indices for barriers by around 25 percent for motorcyclists.

USING LOGISTIC REGRESSION TO IDENTIFY RISK FACTORS CAUSING ROLLOVER COLLISIONS

Rollover collisions are among the most serious collisions that usually result in severe injuries or fatalities. In 2009, there were 8,732 fatal rollover collisions in the United States of America that resulted in the death of 9,833 persons. Those numbers represent approximately 28% and 29% of the total numbers of fatal collisions and fatalities, respectively. The main objective of this paper is to examine the impact of different risk factors that may contribute to this type of serious collision to help develop countermeasures that limit them. To avoid the bias that may be caused by interactions among different drivers, this analysis focuses on rollover related to single-vehicle collisions so that the behavior of the driver of the collided vehicle can be analyzed more effectively. Logistic regression technique is utilized to analyze single-vehicle rollover collisions that occurred on state and interstate highways in the states of Ohio and Washington in 2009. The results obtained from this analysis have the potential to help decision makers identify different strategies to limit the severity of this type of collisions.

Cookie Lover's Crash

A 35-year-old man was brought by ambulance to the emergency department after a single-vehicle collision; he was eating cookies while being extricated from the car. Upon arrival, his face was covered with purple icing. He was not oriented to time or place, his speech was garbled, and he could not follow commands. Vital signs demonstrated tachycardia and hypertension. He …

Field Relevance of the New Car Assessment Program Lane Departure Warning Confirmation Test

The availability of active safety systems, such as Lane Departure Warning (LDW), has recently been added as a rating factor in the U.S. New Car Assessment Program (NCAP). The objective of this study is to determine the relevance of the NCAP LDW confirmation test to real-world road departure crashes. This study is based on data collected as part of supplemental crash reconstructions performed on 890 road departure collisions from the National Automotive Sampling System, Crashworthiness Data System (NASS/CDS). Scene diagrams and photographs were examined to determine the lane departure and lane marking characteristics not available in the original data. The results suggest that the LDW confirmation test captures many of the conditions observed in real-world road departures. For example, 40% of all single vehicle collisions in the dataset involved a drift-out-of-lane type of departures represented by the test. Also, the median total departure velocity for vehicles was 78.9 kph, which is close to the 72.4 kph (45 mph) specified in the LDW test. However, there are some aspects of real-world road departures not included in the test. For example, the test is performed in daylight yet nearly half of all road departure crashes (42%) occurred in the dark. Furthermore, the LDW test is only performed on straight road segments, which corresponds to 48% of real-world departures. The departure speed specified in the LDW test is 0.5 m/s (1.1 mph) whereas the mean lateral departure speed in real world crashes was 4.3 m/s (9.5 mph). Of the examined cases, the LDW test is applicable to approximately 23% of no maneuver road departures, which corresponds to 9% of all single vehicle collisions. Including dark lighting conditions and curved road segments would increase the applicability to 65% of no maneuver departures and 26% of all single vehicle collisions. These results can be applied to the design of future LDW performance tests. Language: en

Crash and burn? Vehicle, collision, and driver factors that influence motor vehicle collision fires

A retrospective population-based case–control study was performed to determine the association between vehicle fires, and vehicle, collision, and driver factors on highways with a posted speed limit of at least 55mph. Data were obtained from the Kentucky Collision Report Analysis for Safer Highways (CRASH) electronic files for 2000–2009 from the Kentucky State Police Records Sections. The results from the final multiple logistic regression show that large trucks were at a higher risk for a collision involving a fire than passenger vehicles and pickup trucks. When controlling for all other variables in the model, vehicles 6 years old and older, driving straight down the highway, and single vehicle collisions were also identified as factors that increase the risk of motor vehicle collision fires on roadways with a posted speed limit of ≥55mph. Of the 2096 vehicles that caught fire, there were 632 (30%) non-fatally injured drivers and 224 (11%) fatally injured drivers. The results of this study have the potential to inform public health messages directed to the transportation industry, particularly semi truck drivers, in regard to fire risk.

Injury Risk in Collisions Involving Buses in Alberta, Canada

With 2000 to 2007 crash data, this study investigated the factors that contributed to injuries in collisions that involved at least one bus in the province of Alberta, Canada. Crashes of all types of buses (e.g., school, transit, intercity) were considered. Four logistic regression models were calibrated: single-vehicle collisions on highways, single-vehicle collisions on nonhighway locations, two-vehicle collisions on highways, and two-vehicle collisions on nonhighway locations. The analysis showed that weather conditions were a significant contributing factor in all four types of collisions, although crashes in adverse weather conditions resulted in fewer injuries. The type of collision, characteristics of collision partner, driver age of collision partner, and weather conditions had a significant effect on the level of severity of collisions on both highway and nonhighway locations. Other factors were shown to affect injury risk only in one particular situation. For instance, for highway-related collisions, the age of the collision partner had a significant effect on levels of accident severity, whereas the age of the bus driver did not. In addition, for highway collisions, the severity was higher for head-on crashes, bus–bus crashes, bus–truck crashes, bus–motorcycle crashes, older buses, crashes on grade and in sags, and crashes during dark and sun glare, whereas accident probability decreased with larger outside shoulder width. For nonhighway locations, crashes occurring near tunnels, overpasses, and signalized intersections were shown to result in a higher probability of injury. The results showed that single-bus collisions involving pedestrians at nonhighway locations had higher injury risk than collisions involving objects.

Vehicle mass as a determinant of fuel consumption and secondary safety performance: A comment

Attention is called to evidence that in collisions between vehicles of equal mass, and in single-vehicle collisions, there is unlikely to be a very strong effect of car size on injury severity, and that variation in crashworthiness within the set of car models of a given size has a much larger effect. Consequently, the secondary safety of a national fleet of small cars in the future could be as high as that of a national fleet of large cars today.

Crashes involving motorised rickshaws in urban India: Characteristics and injury patterns

IntroductionMotorised three-wheeled vehicles (motorised rickshaw) are popular in Asian countries including India. This study aims to describe the crash characteristics and injury patterns for motorised rickshaw occupants and the road users hit-by-motorised rickshaw in urban India. MethodsConsecutive cases of road traffic crashes involving motorised rickshaw, irrespective of injury severity, whether alive or dead, presenting to the emergency departments of two large government hospitals and three branches of a private hospital in Hyderabad city were recruited. Crash characteristics, details of injuries, injury severity parameters and outcome were documented in detailed interviews. ResultsA total of 139 (18%) of the 781 participants recruited were injured as a motorised rickshaw occupant (11%) or were hit by a motorised rickshaw (7%) in 114 crashes involving motorised rickshaw. Amongst motorised rickshaw occupants, single-vehicle collisions (54%) were more frequent than multi-vehicle collisions (46%), with overturning of motorised rickshaw in 73% of the single-vehicle collisions. Mortality (12%), the mean Injury Severity Score (5.8) and rate of multiple injured (60%) indicated a substantial trauma load. No significant differences in injury pattern were found between motorised rickshaw occupants and hit-by-motorised rickshaw subjects, with the pattern being similar to that of the pedestrians and two-wheeled vehicle users. With bivariate analysis for motorised rickshaw occupants, the risk of fatal outcome (odds ratio (OR) 2.60, 95% confidence interval (CI): 0.64–10.54), upper limb injury (OR 2.25, 95% CI: 0.94–5.37) and multiple injuries (OR 2.03, 95% CI 0.85–4.83) was high, although not statistically significant in multi-motorised-vehicle collisions as compared with the single-vehicle collisions or overturning. The risk of having multiple injuries (OR 4.55, 95% CI: 1.15–17.95) was significantly higher in motorised rickshaw occupants involved in front collisions. Being a front-seat motorised rickshaw passenger in a vehicle collision increased the risk of having a fatal outcome (OR 7.37, 95% CI: 0.83–65.66) and a Glasgow coma score≤12 (OR 2.21, 95% CI: 0.49–9.89), although not significantly when compared to the back-seat passengers. ConclusionThese findings can assist with planning to deal with the consequences and prevention of road traffic injuries due to crashes involving motorised rickshaw, given the high use of these and substantial morbidity of related injuries in India. The need for improved understanding of the risk characteristics of motorised rickshaw is highlighted.

Influence of Driver Distractions on the Likelihood of Rear-End, Angular, and Single-Vehicle Crashes in Missouri

Driver distraction has been associated with a higher likelihood of crash involvement. Crash data from the state of Missouri for the years 2001 to 2006 revealed that the highest number of distraction-related crash incidents occurred while drivers were using cell phones or other electronic devices or had passengers in the car. A multinomial logit model was used to predict the odds that a driver with a specific type of distraction would be involved in one of the most frequent crash types, rear-end, angular, or single-vehicle collision, in comparison with each other. Results showed that distractions could have varying influences on crash type. More specifically, passenger-related and cell phone distractions are more likely in angular crashes; for other electronic device–related distractions, the most probable type of crash is a single-vehicle crash. Inferences made in this study should be considered in light of the fact that the data were limited in the number of reported distractions and the study was conducted in only one state. Future research comparing similar distraction factors across other states and nationally may provide a broader view of the type and severity of crashes related to driver distractions.

Single-vehicle collisions in Europe: analysis using real-world and crash-test data

Many European road casualties result from vehicles leaving the road, often impacting roadside obstacles. As part of the European Commission-funded project RISER (Roadside Infrastructure for Safer European Roads), several activities were undertaken to collate the type of real world crash data which is needed to understand single vehicle crash situations and relate this to crash-test data mandated in the European Union. Accident data were collected and used to create databases exclusively for single-vehicle collisions on major rural roads, simulation software was used to further understand impacts with roadside structures, and an inventory of crash-test data was collected for impacts with poles and safety barriers. The combination of accident data, simulations and crash-test data has provided a unique insight into the characteristics of single-vehicle collisions, helping those involved in the design and evaluation of the roadside environment to understand them better and make recommendations for consideration when drafting design guidelines.