Factors influencing injury severity to belted drivers in car crashes in India.

OBJECTIVE: The 2019 revised Indian seat belt regulation resulted in a significant increase in driver belt use. This study examines the factors influencing Maximum Abbreviated Injury Scale (MAIS) 2+ injuries to belted car drivers using Indian crash data. METHODS: Crash data obtained from Road Accident Sampling System-India (RASSI; 2011 to 2020) were used. Analysis was performed on a sample of 662 belted car drivers, representing 1.7 million drivers nationally. Survey logistic regression was used to identify factors influencing the odds of MAIS 2+ injuries to belted car drivers. Factors including delta-V, mass ratio (striking vehicle/struck vehicle), crash type, and driver age and gender were examined. The model fits and the statistical significance of each factor included in the models were examined. In addition, clinical review of crashes with belted drivers sustaining MAIS 3+ injury is presented. RESULTS: Delta-V was the most significant factor (odds ratio = 12%; 95% confidence interval 6%-19%) influencing belted driver injuries. Older drivers (55+ years) have a higher odds of MAIS 2+ injury. By adding mass ratio to the model, the odds ratio for delta-V increased to 1.16. If the mass ratio is 2.5 (striking vehicle weight = 2.5 times struck vehicle weight), then the odds of MAIS 2+ injury for the struck vehicle driver doubles. The average Delta-V for MAIS 2+ crashes is 34 mph and injury risk increases significantly when delta-V approaches 30 mph. Seventy percent of crashes with injured drivers had a mass ratio >2. For drivers with minor/no injuries, 88% of crashes had a mass ratio <2. Review of MAIS 3+ injury crashes showed that these crashes had a high delta-V (38 mph) and high mass ratio (5). Sixty percent of belted drivers sustained MAIS 3+ head or chest injury resulting from reduction in survival space. About 37% of AIS 3+ head injuries were subdural hemorrhages and 20% were crush injury to head. AIS 3+ chest injuries were rib fractures (40%) and lung lacerations/ruptures (27%). CONCLUSION: Delta-V and mass ratio are significant factors of belted driver injuries in India. Serious injuries are mainly to the head and chest. Increased rear underrun protection device (RUPD) fitment rate, improved airbag and RUPD design, safe speed enforcement, and improved road infrastructure will reduce injury severity.

Characteristics of pedestrian injuries caused due to impacts with powered 2-wheelers in India.

Objective: This study aims to understand the nature, severity, and sources of injuries sustained by pedestrians involved in crashes with powered 2-wheelers (PTWs) in India. Further, it aims to understand the pedestrian injury pattern and injury mechanism based on the pedestrian contact location on the PTW. Methods: Eight years of field data from the Road Accident Sampling System-India (RASSI) database were considered for the study. Analyses were performed using both weighted and unweighted RASSI data. A sample of 57 crashes between pedestrians and PTWs was analyzed to determine the pedestrian injury characteristics, pedestrian orientation with PTW, and PTW contact zone (PCZ) or the pedestrian contact location on PTW. The PCZs were classified into 3 types. The risk of sustaining a Maximum Abbreviated Injury Scale (MAIS) injury to the head and pedestrian injury mechanism across the 3 PCZs was analyzed. Results: The results of both weighted and unweighted RASSI data were consistent. About 67% of pedestrians who were killed sustained MAIS 3+ head injuries and 52% of pedestrians with nonfatal injuries sustained MAIS 2+ lower extremity injuries. The risk of MAIS 3+/fatal head injury is notably higher (86%) for pedestrians struck from behind compared to pedestrians struck from the side (36%). Of the 3 PCZs, about 80% of the pedestrians contacting PCZ-1 (corner of the PTW front end) sustained fatal head injuries and only 5% contacting PCZ-2 (center of the PTW front end) sustained fatal head injuries. About 40% contacting PCZ-3 (combination of PCZ-1 and PCZ-2) sustained fatal head injuries. Of all AIS 3+ head injuries, 88% were associated with ground impacts. Of all AIS 2+ lower extremity injuries, 96% were associated with impacts to PTW front-end parts. Conclusions: The results show that head injuries account for most pedestrian fatalities in crashes with PTWs and lower extremity injuries account for most nonfatal injuries. Head injuries are associated with ground contacts and lower extremity injuries are associated with contacting PTW front-end parts. Pedestrians contacting the corner of the PTW are highly prone to MAIS 3+ head injuries, whereas pedestrians contacting the center of the PTW are less prone to MAIS 3+ head injuries. This difference is predominantly because of the varied injury mechanisms seen across PCZs.

Estimating side underride fatalities using field data.

There is evidence that underride events are undercounted by the Fatality Analysis Reporting System (FARS), a census of fatal crashes on public roads in the United States. This study's principal objective was to develop accurate fatality estimates for side underride crashes involving "combination trucks" and light vehicles. Police reports from 29 states were used to estimate the incidence of fatal crashes in which light vehicles underrode the sides of large combination trucks. A protocol was developed to judge the presence of underride with passenger compartment intrusion (PCI), and an in-depth manual review of police reports was performed using scene diagrams, narratives, vehicle and occupant data. The incidence of fatal underride was then compared to that reported in FARS to determine the extent of underreporting in FARS. Further, a comprehensive review of side underride crashes resulting in fatalities and injuries was made using the Large Truck Crash Causation Study (LTCCS) data, the most comprehensive database on large truck crashes. Results show that only a small proportion of the light vehicle occupant fatalities resulting from collisions with combination trucks involve a side underride, and an even smaller proportion involve a side underride with PCI. An in-depth review shows the ratio of underreporting of side underride crashes in FARS is a factor of 3.1 (CI: 2.9-3.3); thus, the annual number of light vehicle side underride fatalities with PCI is estimated to be 202 (CI: 189-215). Comparison of FARS / LTCCS data shows results consistent with this underreporting estimate. LTCCS data also shows that non-fatal serious injuries to light vehicle occupants in side underride crashes involving combination trucks are extremely rare.

A comprehensive review of rollover accidents involving vehicles equipped with Electronic Stability Control (ESC) systems.

This study investigated 478 police accident reports from 9 states to examine and characterize rollover crashes involving ESC-equipped vehicles. The focus was on the sequence of critical events leading to loss of control and rollover, and the interactions between the accident, driver, and environment. Results show that, while ESC is effective in reducing loss of control leading to certain rollover crashes, its effectiveness is diminished in others, particularly when the vehicle departs the roadway or when environmental factors such as slick road conditions or driver factors such as speeding, distraction, fatigue, impairment, or overcorrection are present.

Seat integrated and conventional restraints: a study of crash injury/fatality rates in rollovers.

This study used police-reported motor vehicle crash data from eleven states to determine ejection, fatality, and fatal/serious injury risks for belted drivers in vehicles with conventional seatbelts compared to belted drivers in vehicles with seat integrated restraint systems (SIRS). Risks were compared for 11,159 belted drivers involved in single- or multiple-vehicle rollover crashes. Simple driver ejection (partial and complete), fatality, and injury rates were derived, and logistic regression analyses were used to determine relative contribution of factors (including event calendar year, vehicle age, driver age/gender/alcohol use) that significantly influence the likelihood of fatality and fatal/serious injury to belted drivers in rollovers. Results show no statistically significant difference in driver ejection, fatality, or fatal/serious injury rates between vehicles with conventional belts and vehicles with SIRS.

Kid in the middle: a discussion of effectiveness of center rear-seat restraint systems.

This paper examines effectiveness of rear seat restraint systems in reducing injury in frontal and side impacts. Results indicate effectiveness varies by crash configuration and occupant age, with age being the most important factor influencing odds of fatality/serious injury to belted, rear seated occupants in frontal and side crashes. There is no significant difference between center lap and outboard lap/shoulder belts effectiveness; however, field data shows a high percentage of misuse (wearing belts improperly or using age-inappropriate belts) associated with fatalities and serious injuries. Review of NASS/CDS cases on seriously injured belted children shows belt misuse and injury patterns that might be mitigated by booster seats or proper use of adult belts.

Occupant injury experience in rollover crashes: an in-depth review of NASS/CDS data.

National Automotive Sampling System (NASS) crash statistics were examined to understand injury patterns of belted occupants in rollover crashes and determine accuracy / completeness of selected NASS-coded variables. A comprehensive statistical study, followed by detailed engineering reviews of 278 NASS cases, is in progress. The primary objective is to understand rollover crash characteristics and their influence on rollover injury severity. Focus was on cases with "roof contact" as the injury source. Two groups- significant roof deformation with no injury, and significant injury with minimal roof deformation-are discussed, as are crash characteristics such as "arrested roll." Also, based on evaluation of existing NASS codes, recommendations are made to enhance NASS coding of rollover-related variables.

Influences of vehicle size and mass and selected driver factors on odds of driver fatality.

Research was undertaken to determine vehicle size parameters influencing driver fatality odds, independent of mass, in two-vehicle collisions. Forty vehicle parameters were evaluated for 1,500 vehicle groupings. Logistic regression analyses show driver factors (belt use, age, drinking) collectively contribute more to fatality odds than vehicle factors, and that mass is the most important vehicular parameter influencing fatality odds for all crash configurations. In car crashes, other vehicle parameters with statistical significance had a second order effect compared to mass. In light truck-to-car crashes, "vehicle type-striking vehicle is light truck" was the most important parameter after mass, followed by vehicle height and bumper height, with second order effect. To understand the importance of "vehicle type" variable, further investigation of vehicle "stiffness" and other passenger car/light truck differentiating parameters is warranted.