Crash Involvement Rates Research Articles

Does a cautious driving style reduce the crash risk of older drivers? An analysis using a novel driving style recognition method

Older drivers who are aware of their declining functions tend to adopt a cautious driving style to compensate for their declining driving abilities. However, whether cautious older drivers are associated with a reduced crash risk has not been well studied. In this study, we examined the association between older drivers’ cautious driving style and crash risk using a novel driving style recognition method. We proposed a driving style recognition method that does not require predefined thresholds and applied it to the driving data of 71 drivers comprising 59 drivers aged 65 years or older (mean age 72.4; 67.8 % male) and 12 drivers aged 51–64 years (mean age 58.3; 66.7 % male). Drivers were classified into cautious and relatively aggressive groups based on the classification results of their speed, acceleration, and braking styles. The results showed that cautious drivers were characterized by older age, poorer Trail Making Test Part B performance, less frequent night driving, and lower driving exposure, indicating that older drivers may adopt multiple compensatory strategies. Although the crash involvement rate of cautious older drivers was approximately half that of relatively aggressive drivers, the difference was not statistically significant. Furthermore, this difference was expected to decrease when driving exposure was considered. Older drivers who adopted a cautious driving style but were involved in traffic crashes had poorer visual acuity and contrast sensitivity. The results of this study indicate that a cautious driving style alone may not be sufficient to compensate for older drivers’ declining functions, particularly the loss of two visual functions observed in the present study.

A resampling approach to disaggregate analysis of bus-involved crashes using panel data with excessive zeros

Public bus constitutes more than 70% of the overall road-based public transport patronage in Hong Kong, and its crash involvement rate has been the highest among all public transport modes. Though previous studies had identified explanatory factors that affect the crash risk of buses, use of considerably imbalanced crash data with excessive zero observations could lead to inaccurate parameter estimation. This study aims to resolve the excess zero problem of disaggregate analysis of bus-involved crashes based on synthetic data using a Synthetic Minority Over-Sampling Technique for panel data (SMOTE-P). Dataset comprising crash, traffic, and road inventory data of 88 road segments in Hong Kong during the period from 2014 to 2017 is used. To assess the data balancing performance, other common data generation approaches such as Random Under-sampling of the Majority Class (RUMC) technique, Cluster-Based Under-Sampling (CBUS), and mixed resampling, are also considered. Random effect Poisson (REP) models based on synthetic data and random effect zero-inflated Poisson (REZIP) model based on original data are estimated. Results indicate that REP model based on synthetic data using SMOTE-P outperforms REZIP model based on original data and REP models based on synthetic data using RUMC, CBUS and mixed approaches, in terms of statistical fit, prediction error, and explanatory factors identified. Results of model estimation based on SMOTE-P suggest that factors including morning peak, evening peak, hourly traffic flow, average lane width, road length, bus stop density, percentage of bus in the traffic stream, and presence of bus priority lane all affect the bus-involved crash frequency. More importantly, this study provides a feasible solution for disaggregate crash analysis with imbalanced panel data.

Modelling the relationship of driver license and offense history with fatal and serious injury (FSI) crash involvement

Introduction: Previous research has indicated that increases in traffic offenses are linked to increased crash involvement rates, making reductions in offending an appropriate measure for evaluating road safety interventions in the short-term. However, the extent to which traffic offending predicts fatal and serious injury (FSI) crash involvement risk is not well established, prompting this new Victorian (Australia) study. Method: A preliminary cluster analysis was performed to describe the offense data and assess FSI crash involvement risk for each cluster. While controlling demographic and licensing variables, the key traffic offenses that predict future FSI crash involvement were then identified. The large sample size allowed the use of machine learning methods such as random forests, gradient boosting, and Least Absolute Shrinkage and Selection Operator (LASSO) regression. This was done for the ‘all driver’ sample and five sometimes overlapping groups of drivers; the young, the elderly, and those with a motorcycle license, a heavy vehicle license endorsement and/or a history of license bans. Results: With the exception of the group of drivers who had a history of bans, offense history significantly improved the accuracy of models predicting future FSI crash involvement using demographic and licensing data, suggesting that traffic offenses may be an important factor to consider when analyzing FSI crash involvement risk and the effects of road safety countermeasures. Conclusions: The results are helpful for identifying driver groups to target with further road safety countermeasures, and for showing that machine learning methods have an important role to play in research of this nature. Practical Application: This research indicates with whom road safety interventions should particularly be applied. Changes to driver demerit policies to better target offenses related to FSI crash involvement and repeat traffic offenders, who are at greater risk of FSI crash involvement, are recommended.

Continued trends in older driver crash involvement rates in the United States: Data through 2017–2018

Introduction: With the growing older adult population due to the aging baby-boom cohort, there was concern that increases in fatal motor-vehicle crashes would follow. Yet, previous analyses showed this to be untrue. The purpose of this study was to examine current trends to determine if previous declines have persisted or risen with the recent increase in fatalities nationwide. Methods: Trends among drivers ages 70 and older were compared with drivers 35–54 for U.S. passenger vehicle fatal crash involvements per 100,000 licensed drivers from 1997 to 2018, fatal and all police-reported crash involvements per vehicle miles traveled using the 1995, 2001, 2009, and 2017 National Household Travel Surveys, and driver deaths per 1,000 crashes. Results: Since the mid-1990s, fatal crashes per licensed driver trended downward, with greater declines for drivers ages 70 and older than for middle-aged drivers (43% vs. 21%). Fatal crash rates per 100,000 licensed drivers and police-reported crash rates per mile traveled for drivers ages 70–79 are now less than those for drivers ages 35–54, but their fatal crash rates per mile traveled and risk of dying in a crash remain higher as they drive fewer miles. As the economy improved over the past decade, fatal crash rates increased substantially for middle-aged drivers but decreased or remained stable among older driver age groups. Conclusions: Fatal crash involvements for adults ages 70 and older has recently increased, but they remain down from their 1997 peak, even as the number of licensed older drivers and the miles they drive have increased. Health improvements likely contributed to long-term reductions in fatal crash rates. As older drivers adopt vehicles with improved crashworthiness and safety features, crash survivability will improve. Practical Application: Older adults should feel confident that their independent mobility needs pose less risk than previously expected.

Crash rates of convertible cars

Objective Convertible cars have existed since among the first automobiles, and the lack of substantial roof structure creates some safety concerns. Though crash tests have demonstrated that convertibles can resist excessive intrusion in front and side crashes and that strong A-pillars and roll bars can help maintain survival space in rollovers, little work has been done examining the real-world crash experience of these vehicles. The objective of this study was to compare the crash experience of recent convertibles with nonconvertible versions of the same cars using the most recent crash data. Methods Crash and exposure data were obtained from the U.S. Department of Transportation and IHS Markit, respectively. Rates of driver deaths and police-reported crash involvements were compared for 1- to 5-year-old convertible cars and their nonconvertible versions during 2014–2018. Exposure measures included registered vehicle years (RVY) and vehicle miles traveled (VMT). These rates were compared using the standardized mortality ratio to account for possible differences in exposure distribution. Crash circumstances (e.g., point of impact, rollover, ejection) and behavioral outcomes (e.g., speeding, alcohol impairment, seat belt use) were compared for drivers killed in crashes. Results Convertibles had lower driver death rates and police-reported crash involvement rates on the basis of both RVY and VMT. However, the differences in driver death rates were not statistically significant. Driver deaths per 10 billion VMT were 11% lower for convertibles, and driver involvement in police-reported crashes per 10 million VMT was 6% lower. On average, convertibles were driven 1,595 fewer miles per year than the nonconvertible versions of these cars. Among fatally injured drivers, convertibles had slightly higher rates of ejection, and behavioral differences were minimal. The number of rollovers was small and their rate did not substantially differ between convertibles and their nonconvertible versions. Conclusions Safety concerns associated with convertibles’ retractable roof structures were not supported by the results of this study.

Bicycle Rider Behavior and Crash Involvement in Australia.

This research investigated how behaviours and attitudes of bicycle riders influence crash frequency and severity. The study recruited 1102 Australian bicycle riders for an online survey. The survey comprised questions on demographics, frequency of riding and the number and severity of traffic crashes during the last five years. The survey included the Cycling Behaviour Questionnaire and the Cyclist Risk Perception and Regulation Scale. Overall, there were low levels of errors and violations reported by participants indicating that these behaviours were on average never or rarely exhibited while riding a bicycle. Conversely, participants reported high levels of engagement in positive behaviours and reported high levels of traffic rule knowledge and risk perception. Higher rates of violations and errors were associated with increased crash likelihood, while higher rates of positive behaviours were associated with reduced rates of crash involvement in a period of 5 years. The findings highlight the relationship between errors, total crashes and crash severity Further promotion of positive behaviours amongst riders may also help to reduce the risk of crashes.

Comparison of Motor Vehicle Crashes, Traffic Violations, and License Suspensions Between Autistic and Non-Autistic Adolescent and Young Adult Drivers

One-third of autistic individuals obtain a driver's license by age 21 years; however, prior studies suggest they may be at heightened risk for motor vehicle crashes. We compared objective rates of crashes, traffic violations, and license suspensions for newly licensed autistic and non-autistic adolescents. This retrospective cohort study included New Jersey residents born from 1987 through 2000 who were patients of the Children's Hospital of Philadelphia health care network. Electronic health records were linked with statewide driver licensing and crash databases. Autism status was classified via International Classification of Diseases (ICD) diagnostic codes; individuals with intellectual disability were excluded. We compared rates among 486 autistic and 70,990 non-autistic licensed drivers over their first 48 months of driving. Furthermore, we examined the proportion of crashes attributed to specific driver actions and crash types. Compared with non-autistic drivers, autistic drivers were estimated to have lower average monthly rates of crash involvement (adjusted rate ratio (adjRR)= 0.89, 95% CI= 0.75-1.05), moving violations (adjRR= 0.56, 95% CI= 0.48-0.67), and suspensions (adjRR = 0.32, 95% CI=0.18-0.58). Among drivers involved in a crash, autistic drivers were half as likely to crash because of unsafe speed, but substantially more likely to crash because of their failure to yield to a vehicle/pedestrian and while making left-turns or U-turns. Newly licensed autistic adolescent drivers have similar to lower estimated rates of adverse driving outcomes; the extent to which these can be attributed to different driving patterns is a critical point for future investigation. There were several notable differences in the characteristics of these crashes, which directly inform interventions to improve driving safety of autistic adolescent drivers.

Roles of personal and environmental factors in the red light running propensity of pedestrian: Case study at the urban crosswalks

Pedestrian is vulnerable to mortality and severe injury in road crashes. Red light running violation of pedestrians is one of the leading causes to the crashes at signalized intersections, at which the crash involvement rates of pedestrians are high. Therefore, it is important to identify the factors that affect the propensity of red light running of pedestrian. In this study, effects of both personal factors (pedestrians’ demographics and behavior) and environmental factors (presence and behavior of other pedestrians, signal time, and traffic condition) on the individual decision of red light running violation are examined, using the video observation surveys at the signalized crossings that are prone to pedestrian-vehicle crashes and have moderate pedestrian and vehicular traffic volumes in the urban area. Crossing behaviors of 6320 pedestrians are captured. Results of a random parameter logit model indicate that pedestrian gender, age, number of lanes, presence of a companion, number of pedestrians around, presence of other violators in the same cycle, time to green, red time, traffic volume, and percentage of heavy vehicles all affect the propensity of red light running violation of pedestrians. Also, there are significant interaction effects by pedestrian’s gender and age, presence of other violators, with a companion, and traffic volume on the propensity. Findings are indicative to the development of effective engineering, enforcement and educational initiatives combating the red light running violation behavior of pedestrians. Therefore, pedestrian safety level at the signalized intersections can be enhanced.

Older Driver Crash Involvement and Fatalities, by Age and Sex, 2000-2017.

Federal reporting of crash fatalities has limited age-by-sex stratification, but both age and sex are associated with driving reduction and cessation. We described older driver fatal crash involvement and fatalities using Fatality Analysis Reporting System data to calculate rates (per 100,000 licensed drivers, per 100,000 population) with age-by-sex stratifications. Nationally from 2000 through 2017, 110,422 drivers 65+ were involved in crashes resulting in at least one death within 30 days, and 67,843 of these older drivers died. Involvement and fatality rates per 100,000 licensed drivers in 2017 were lowest for females 65-69 (7.7 and 3.6, respectively) and highest for males age 85+ (34.3 and 25.5, respectively). Females had lower driver fatal crash involvement and fatality rates throughout the lifespan, even when rates generally decreased over time. Elaborating fatal crash trends and rates by age and sex helps to differentiate the public health burden of older driver crashes and fatalities.

Frailty phenotype associated with traffic crashes among older drivers: A cross-sectional study in rural Japan

IntroductionIn places such as Japan, driving safety and physical frailty are two urgent issues due to a rapidly aging population. However, few studies have focused on whether physical frailty is associated with traffic crashes among older drivers. This cross-sectional study aimed to investigate the association between frailty phenotype and self-reported traffic crashes in the past year among Japanese community-dwelling older adults. MethodsThe sample consisted of 349 community-dwelling older drivers (aged 74.4 ± 5.0 years) enrolled in the Kasama Health Checkup for Longevity survey in rural Japan. The Japanese version of the Cardiovascular Health Study was used to classify participants into a pre-frail/frail group (n = 155, 44.4%) and a robust group (n = 194, 55.6%). Physical and cognitive function were evaluated using performance-based measures, the Geriatric Depression Scale (GDS) was used to evaluate depressive symptoms, and information on risky driving behaviors and traffic crashes was obtained from a self-report questionnaire. ResultsCompared to robust participants, pre-frail/frail participants demonstrated poorer physical function, scored lower on a total five cognitive functions test (5-Cog), and were more prone to depression. Additionally, pre-frailty/frailty (34.2%) was significantly associated with near-miss traffic incidents, compared to robustness (18.0%). Moreover, 46 participants reported involvement in traffic crashes in the past year (33 of 46 were pre-frail/frail). After adjusting for age, sex, total 5-Cog scores, GDS scores, driving distances, and near-miss traffic incidents, pre-frail/frail participants showed higher rates of traffic crash involvement in the past year than robust participants (OR = 3.74, 95% CI: 1.75–7.96). ConclusionFrailty phenotype was shown to be associated with an increased rate of traffic crashes. Our findings can be applied to inform health promotion policies and provide timely interventions designed to improve driving safety among pre-frail/frail older adults.

Associations between self-rated personality traits and automobile fatality rates across small geographic areas

We explore how variation in fatal automobile crashes across small geographic areas is associated with geographic variation in self-rated psychological and behavioral characteristics. Specifically, estimates of ZIP-code-level automobile fatality rates were linked to a separate dataset comprising 2.8 million responses to a widely used self-report personality questionnaire. To control for an area's wealth and population density, associations were estimated at the slightly larger level of US Census ZIP Code Tabulation Areas (ZCTAs). Relationships were estimated using an intraclass adjustment method, where the estimated correlation between individual scores and ZCTA-level fatality rates was divided by the square root of the estimated within-ZCTA intraclass correlation. Further, the ZCTA-level correlation was estimated separately for each US state to examine the consistency of associations. Rates of fatal crash involvement tended to be higher in areas where respondents were more likely to describe themselves as being depressed, moody, and quarrelsome. Some relationships were less intuitive; for instance, rates of fatal crash involvement tended to be higher in areas where respondents described themselves as more helpful and as less easily distracted. However, many small-area-level associations between self-rated personality and fatality rates were found to be in the same direction across more states than expected by chance. This pattern indicates that even many of the less intuitive associations were often highly reliable and general, which has implications for identifying geographic areas with heightened automobile fatality risk.

Traffic Safety and Older Drivers

Older adults, defined as individuals aged 65 years and older, comprise the fastest-growing segment of the United States population, with a projected increase to 53 million by 2030. 1 United States Census BureauProjections of the size and composition of the U.S. population: 2014 to 2060. https://www.census.gov/content/dam/Census/library/publications/2015/demo/p25-1143.pdf Google Scholar As the older adult population continues to grow, the number of older drivers will increase. 2 FHWA press releaseOlder drivers set record for second year. Licensed drivers over 65 continue to increase, teen drivers remain at near-record laws [Press Release]. Washington, DC: U.S. Department of Transportation, Office of Public Affairs. https://www.fhwa.dot.gov/pressroom/fhwa1720.cfm Google Scholar It is anticipated that there will be an increase in fatalities and injuries from motor vehicle crashes (MVCs) among older drivers. 3 Cicchino J.B. McCart A.T. Trends in older driver crash involvement rates and survivability in the United States: an update. Accid Anal Prev. 2014; 72: 44-54https://doi.org/10.1016/j.aap.2014.06.011 Crossref PubMed Scopus (51) Google Scholar Currently, MVC is ranked as the second leading cause of injury-related death, after falls, among persons 65 years and older. 4 Centers for Disease ControlTen Leading Cause of Death by Age Group. https://www.cdc.gov/injury/images/lc-charts/leading_causes_of_death_by_age_group_2017_1100w850h.jpg Google Scholar Common age-related changes that impact functional abilities, in addition to medical conditions and medications, can heighten an older driver’s crash risk. 3 Cicchino J.B. McCart A.T. Trends in older driver crash involvement rates and survivability in the United States: an update. Accid Anal Prev. 2014; 72: 44-54https://doi.org/10.1016/j.aap.2014.06.011 Crossref PubMed Scopus (51) Google Scholar A decreased physiologic reserve to respond to injury increases the risk of morbidity and mortality in this population. 3 Cicchino J.B. McCart A.T. Trends in older driver crash involvement rates and survivability in the United States: an update. Accid Anal Prev. 2014; 72: 44-54https://doi.org/10.1016/j.aap.2014.06.011 Crossref PubMed Scopus (51) Google Scholar In addition, these normal age-related changes complicate the assessment of older patients with trauma. 5 Emergency Nurses AssociationSpecial populations: the geriatric trauma patient. in: Denke N. Trauma Nursing Core Course Provider Manual. 8th ed. Jones and Bartlett Learning, Burlington, MA2020: 261-275 Google Scholar Thus, caring for this special population is a clinical challenge for emergency nurses. 5 Emergency Nurses AssociationSpecial populations: the geriatric trauma patient. in: Denke N. Trauma Nursing Core Course Provider Manual. 8th ed. Jones and Bartlett Learning, Burlington, MA2020: 261-275 Google Scholar Thelma C. Kuska, Member, IL ENA, is Chair, Injury Prevention Committee and Government Affairs Committee, Emergency Nurses Association Illinois State Council, Palos Heights, IL.

Modeling Impacts of Speed Reduction on Traffic Efficiency on Expressway Uphill Sections

Road geometric design is a key factor impacting driving safety and efficiency. In highway profile design, speed reduction is used to determine critical length of grade. Previous research generally concentrated on the relationship between speed reduction and crash involvement rate to establish the recommended value. Limited research results have been reported at this point concerning speed reduction and traffic efficiency. This study aims to fill the gap by investigating tolerable speed reduction with different vertical slopes considering traffic efficiency. Firstly, appropriate experimental sections were determined after field survey. Traffic data including vehicle count, timely speed, vehicle type, and headway time were then collected on an expressway in Shaanxi Province. The associated traffic efficiency was derived from traffic volume and average speed. After this, the modeling between speed reduction and traffic efficiency was processed with different slopes. The correlation between speed reduction and traffic efficiency was therefore verified. Finally, the prediction model of optimum speed reduction concerning traffic efficiency under different vertical slopes was introduced. It was found that the critical length of grade can be longer with traffic efficiency as the major design control incorporated with slopes of 3–3.5%. The existing regulation in critical length of grade at 3.5–5% can benefit both safety and efficiency. The findings can provide a reference for vertical alignment design, leading to high-efficiency road systems.

An investigation of the relationship between demographic variables, driving behaviour and crash involvement risk of bus drivers: a case study from Iran

The aim of this study was to model bus drivers’ crash involvement risk as a function of their demographic factors and driving behaviour. 177 bus drivers completed the bus driver risk index questionnaire. 19.2% of respondents had been involved in at least one at-fault crash during the past 3 years. In addition, age group and having a second job were found to affect the crash involvement rate. Smoker drivers reported significantly lower scores in patient driving and anxious driving factors. Results also indicated that vehicle ownership could improve hazard monitoring and thrill-seeking behaviours of bus drivers. Logistic regression suggested that drivers ≥55 years old are 5.4 times more likely to be involved in crashes, compared with drivers <35 years old. Model results also implied that the odds of crash involvement would decrease by 39% for each one-unit improvement in the scores of hazard monitoring behaviour. Implications are further discussed.

Crash Involvement and Risky Riding Behaviors among Delivery Riders in China: The Role of Working Conditions

Delivery riders (usually e-bike riders employed in the delivery industry), an emerging occupation as a result of the booming of online commerce in China, have attracted social controversies for the prevalence of unsafe riding and high rates of crash involvement. Given their ever-increasing number and stressful working conditions, more attention should be paid to safety issues involving delivery riders. To illuminate the role of working conditions in influencing safety-related risks of delivery riders, this cross-sectional study was conducted among 824 delivery riders, who answered a self-administered questionnaire gathering information about their demographics, working conditions, riding behaviors, and crash involvement. A mixed probit model of the number of crashes involving riders that allowed for hierarchical relationships between the latent variables identified (i.e., time pressure, fatigue, risky riding behaviors) was employed to determine the underlying association between factors surveyed. The results portrayed a picture of worrisome working conditions for delivery riders. Respondents reported an average of 9.1 daily working hours with insufficient rest. Frequent stair climbing, route planning, and disputes with customers also added to their physical and mental workload. The tested model indicated that a heavy workload, feelings of fatigue, as well as risk-taking behaviors all exerted direct and significant impacts on the involvement in crashes, and time pressure as well as several work-related traits affected crash involvement indirectly, through influencing riders’ feeling of fatigue and riding behaviors. Findings of this study may provide an empirical basis for road safety interventions for delivery riders in China.

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.

Real-world effects of rear automatic braking and other backing assistance systems

Objective: To evaluate the effects of rearview cameras, rear parking sensors, and rear automatic braking systems on backing crashes. Method: Negative binomial regression was used to compare police-reported backing crash involvements per insured vehicle year in 23 US states during 2012–2015 among General Motors vehicles with Rear Vision Camera alone; Rear Parking Assist alone (rear parking sensors); Rear Vision Camera and Rear Parking Assist; or the Rear Vision Camera, Rear Parking Assist, and Rear Automatic Braking to vehicles with none of these systems. Modeling controlled for other backing assistance systems on vehicles and factors that may affect crash risk. Results: The combination of Rear Vision Camera and Rear Parking Assist reduced backing crash involvement rates by 42%. When Rear Automatic Braking was added to the Rear Vision Camera and Rear Parking Assist, vehicles with all three systems had backing crash involvement rates that were 78% lower than vehicles with none of the systems. On vehicles with Rear Parking Assist alone or Rear Vision Camera alone, backing crash involvement rates were reduced 28% and 5%, respectively, but these reductions were not statistically significant. Conclusions: Rearview cameras and rear parking sensors are preventing some backing crashes, but their effectiveness may be constrained in part by drivers not using or responding to the systems appropriately. Rear automatic braking adds to the effectiveness of these systems because it does not rely entirely on appropriate driver response. Practical applications: Rear parking sensors and rearview cameras are available on most new vehicles, but availability of rear automatic braking is limited. If more vehicles were equipped with rear automatic braking that performed like the system evaluated in the current study, many backing crashes that still occur among vehicles with rearview cameras and rear parking sensors could be prevented.

Field effectiveness evaluation of advanced driver assistance systems

Objective: Advanced driver assistance systems (ADAS) are a class of vehicle technologies designed to increase safety by providing drivers with timely warnings and autonomously intervening to avoid hazardous situations. Though laboratory testing suggests that ADAS technologies will greatly impact crash involvement rates, real-world evidence that characterizes their effectiveness is still limited. This study evaluates and quantifies the association of ADAS technologies with the likelihood of a moderate or severe crash for new-model BMWs in the United States.Methods: Vehicle ADAS option information for the cohort of model year 2014 and later BMW passenger vehicles sold after January 1, 2014 (n = 1,063,503), was coded using VIN-identified options data. ADAS technologies of interest include frontal collision warning with autonomous emergency braking, lane departure warning, and blind spot detection. BMW Automated Crash Notification system data (from January 2014 to November 2017) were merged with vehicle data by VIN to identify crashed vehicles (n = 15,507), including date, crash severity (delta V), and area of impact. Using Cox proportional hazards regression modeling, the study calculates the adjusted hazard ratio for crashing among BMW passenger vehicles with versus without ADAS technologies. The adjusted percentage reduction in moderate and severe crashes associated with ADAS is interpreted as one minus the hazard ratio.Results: Vehicles equipped with both autonomous emergency braking and lane departure warning were 23% less likely to crash than those not equipped (hazard ratio [HR] = 0.77; 95% confidence interval [CI], 0.73–0.81), controlling for model year, vehicle size and body type. Autonomous emergency braking and lane departure warning generally occur together, making it difficult to tease apart their individual effects. Blind spot detection was associated with a 14% reduction in crashes after controlling for the presence of autonomous emergency braking and lane departure warning (HR =0.86; 95% CI, 0.744–0.99). Differences were observed by vehicle type and crash type. The combined effect of autonomous emergency braking and lane departure warning was greater in newer model vehicles: Equipped vehicles were 13% less likely to crash (HR =0.87; 95% CI, 0.79–0.95) among 2014 model year vehicles versus 34% less likely to crash (HR =0.66; 95% CI, 0.57–0.77) among 2017 model year vehicles.Conclusion: This robust cohort study contributes to the growing evidence on the effectiveness of ADAS technologies.

Effects of blind spot monitoring systems on police-reported lane-change crashes

Objective: The objective of this study was to examine the effectiveness of blind spot monitoring systems in preventing police-reported lane-change crashes.Methods: Poisson regression was used to compare crash involvement rates per insured vehicle year in police-reported lane-change crashes in 26 U.S. states during 2009–2015 between vehicles with blind spot monitoring and the same vehicle models without the optional system, controlling for other factors that can affect crash risk.Results: Crash involvement rates in lane-change crashes were 14% lower (95% confidence limits −24% to −2%) among vehicles with blind spot monitoring than those without.Discussion: Blind spot monitoring systems are effective in preventing police-reported lane-change crashes when considering crashes of all severities. If every U.S. vehicle in 2015 were equipped with blind spot monitoring that performed like the study systems, it is estimated that about 50,000 crashes could have been prevented.

How does intersection field of view influence driving safety in an emergent situation?

Restricted intersection field of view (IFOV) can influence drivers’ hazard detection abilities and driving safety in an emergent traffic event. However, no field studies or crash-data analyses have been conducted to prove the adequateness of the current intersection sight-distance design standards, which are adopted to ensure that the approaching-intersection drivers have a sufficient field of view to detect traffic hazards and travel safely at intersections. In this study, we conducted a driving simulator experiment to compare drivers’ behavioral and eye-movement measures between different IFOV conditions that met the current intersection sight distance design standards. We examined the influencing mechanism of IFOV on the drivers' collision avoidance process being composed of three consequential stages, respectively in terms of search stage, decision stage and action stage. Our experiment results showed that restricted IFOV impacts the three-stage driving performance interlockingly. Enlarging IFOV can significantly improve drivers' performance in detecting a conflicting vehicle more timely, having a longer perception-reaction time in monitoring the hazard, spending more time on observing intersection surroundings, and taking brake actions earlier and more smoothly so that drivers were more likely to successfully avoid colliding with the conflicting vehicle. In addition, we found that compared with female drivers, male drivers were less likely to take brake actions to avoid a potential collision and had a lower deceleration rate in the braking stage of collision avoidance while there was no significant gender difference in crash involvement rates. The findings indicated that male drivers were more skillful in vehicle control than female drivers. Nevertheless, male drivers had less traffic-crash expectation, which degraded their overall crash avoidance effect. Considering the traffic safety that more than five million intersection-related crashes occur in American each year, these experimental findings have implications for public safety and health.