Prospective assessment of the effectiveness of autonomous emergency braking in car-to-cyclist accidents in France.

Objective: This study aimed to assess the effectiveness of autonomous emergency braking (AEB) systems in car-to-cyclist frontal collisions by simulating their effects, in terms of crash avoidance and injury mitigation, on a representative target population of real-world accidents. Identifying effectiveness-critical AEB-cyclist design parameters through a sensitivity analysis was also targeted.Methods: The analysis is based on a representative set of real-world car-to-cyclist frontal collisions gathered from French police reports. AEB-cyclist-relevant accident cases were first selected and used to build injury risk curves for fatal, severe, and slight cyclist injuries. The effect of AEB-cyclist on these cases was then simulated by means of a car kinematic model involving sensor detection strategies and actuator actions. Combining the resulting simulated impact speed distributions with the injury risk curves allowed to assess AEB-cyclist's effectiveness in terms of lives saved and mitigated injuries. Using design of experiments methods, the sensitivity of this effectiveness with regards to AEB-cyclist design parameters could be assessed.Results: Cyclist injury risks curves were built, along with their confidence intervals, for fatal, severe, and slight injuries using a polytomous complementary log-log regression model, with squared impact speed as an independent variable. A sensitivity analysis on an ideal bisensor AEB-cyclist setting highlighted influential design parameters such as maximal braking intensity or crucial decision algorithm parameters such as maximal time and distance to collision thresholds. AEB-cyclist effectiveness was nevertheless shown to range from 35% to 59% in fatalities, 14% to 54% in severe injuries, and 11% to 42% in slight injuries, depending on field of view parameters alone, once reference values of decision algorithm parameters had been set.Conclusions: This study illustrates the potential benefits and limits of AEB-cyclist systems. High-end systems show acceptable effectiveness rates, but road safety performance strongly depends on external factors such as road surface conditions or has to be tuned in order to avoid unnecessary activations and driver discomfort. Limits of the system's everyday use (lack of maintenance, driver reaction time to collision warnings, etc.) were not taken into account, thus resulting in optimistic evaluations of AEB-cyclist effectiveness.

Comparing motor-vehicle crash risk of EU and US vehicles.

OBJECTIVE: This study examined the hypotheses that passenger vehicles meeting European Union (EU) safety standards have similar crashworthiness to United States (US) -regulated vehicles in the US driving environment, and vice versa. METHODS: The first step involved identifying appropriate databases of US and EU crashes that include in-depth crash information, such as estimation of crash severity using Delta-V and injury outcome based on medical records. The next step was to harmonize variable definitions and sampling criteria so that the EU data could be combined and compared to the US data using the same or equivalent parameters. Logistic regression models of the risk of a Maximum injury according to the Abbreviated Injury Scale of 3 or greater, or fatality (MAIS3+F) in EU-regulated and US-regulated vehicles were constructed. The injury risk predictions of the EU model and the US model were each applied to both the US and EU standard crash populations. Frontal, near-side, and far-side crashes were analyzed together (termed "front/side crashes") and a separate model was developed for rollover crashes. RESULTS: For the front/side model applied to the US standard population, the mean estimated risk for the US-vehicle model is 0.035 (sd = 0.012), and the mean estimated risk for the EU-vehicle model is 0.023 (sd = 0.016). When applied to the EU front/side population, the US model predicted a 0.065 risk (sd = 0.027), and the EU model predicted a 0.052 risk (sd = 0.025). For the rollover model applied to the US standard population, the US model predicted a risk of 0.071 (sd = 0.024), and the EU model predicted 0.128 risk (sd = 0.057). When applied to the EU rollover standard population, the US model predicted a 0.067 risk (sd = 0.024), and the EU model predicted 0.103 risk (sd = 0.040). CONCLUSIONS: The results based on these methods indicate that EU vehicles most likely have a lower risk of MAIS3+F injury in front/side impacts, while US vehicles most likely have a lower risk of MAIS3+F injury in llroovers. These results should be interpreted with an understanding of the uncertainty of the estimates, the study limitations, and our recommendations for further study detailed in the report.

Relation Between Sacroilium and Other Pelvic Fractures Based on Real-World Automotive Accidents.

The study firstly aimed at looking whether sacroilium (SI) fractures could be sustained as unique pelvic injuries in side impact real world automotive accidents. Secondarily, the sacroilium fractures observed in conjunction with other pelvic fractures were analyzed to investigate the existence of injury association patterns. Two real world accident databases were searched for SI fractures. The occupants selected were front car passengers older than 16, involved in side, oblique or frontal impact, with AIS2+ pelvic injuries. In frontal impact, only the belted occupants were selected. The cases were sorted by the principal direction of force (dof) and the type of pelvic injury, namely SI, pubic rami, iliac wing, acetabulum, pubic symphysis, and sacrum injuries. The relation between SI and pubic rami injuries were investigated first. The first database is an accident database composed of cases collected in France by car manufacturers over a period of approximately 40 years. In total it contains approximately 28 000 occupants involved in all types of accident configurations. The occupant injuries, as well as the vehicle deformations, are described in detail. The second database gathered accident cases from 7 zones monitored in Great Britain over a period ranging from 1998 to 2005. All the cases collected include at least one towed away vehicle with at least one injured occupant. In total the database contains approximately 15 000 occupants. The occupant injuries are described in details and autopsy reports were screened when available. Results - In the French database, 39 occupants sustained SI fractures. Out of 39 SI fractures, 32 were associated with pubic rami fractures and 5 additional were associated with other pelvis ring fractures. In the UK database, 46 occupants sustained SI fractures. Out of 46 SI fractures, 34 were associated with pubic rami fractures and 8 additional were associated with other pelvis ring fractures. In side impact (dof 2, 3, 4, 8, 9 or 10 o'clock), in the cases where the side is known for both the SI fractures and pelvic ring injuries, both injuries were on the same side in 70% of the cases. Overall, out of 85 SI fractures cases, only one was clearly identified as occurring with no other pelvic injury and 3 with pelvic injuries other than pelvic ring injury. Conclusions - Overall, from the real world automotive accidents selected at any dof, SI fractures were observed to be associated with other pelvic ring fractures in 96% of the cases. On the reverse, in side impact (dof 2, 3, 4, 8, 9 or 10 o'clock in the LAB database), 89% of the pubic rami fractures occurred without any SI fractures. From a mechanical standing point, it suggests that the SI fractures is a structure more resistant than the rest of the pelvic ring. Overall, 70% of SI fractures were observed in various types of side impacts and 30% in frontal impacts.

A comprehensive overview of the frequency and the severity of injuries sustained by car occupants and subsequent implications in terms of injury prevention.

The objective of the paper is to give an overview of the road injuries issues in France in the 2010's by determining the frequency and the severity of injuries sustained by car occupants, and to infer the implications in terms of vehicule safety. Three types of analysis are conducted. First, we present a time series analysis at a macro statistical level showing a dramatic decrease of injured and fatally injured occupants in passenger cars compared to other modes of road transport. Secondly, we propose a descriptive statistical analysis of the injuries (frequency and severity) sustained by car occupants, by body regions, using the AIS. Finally we propose some insights into the effectiveness of some safety features. French National crash census (BAAC) is used for a general overview of injury frequencies and raw severity scores (fatal, hospitalized, slighty injured) in car crashes. In-depth crash investigations data are used to specify the body regions and the severity of the injuries sustained by car occupants. Data show that car occupants mortality and morbidity decreased more over the last decade than other road modes: -58 % fatalities and -64 % hospitalized (compared to -39% and -55% for pedestrians, and -21% and -44% for motorcyclists for example). In crashes for which at least one person has been injured, 19 % of occupants are uninjured, 49 % of occupants sustain MAIS 1 injuries, 15 % MAIS2, 8% MAIS 3, and 9 % MAIS 4+. Regardless of seat belt use, the body regions most often injured are head, upper and lower extremities and thorax. However, at least two third up to 92% of involved persons sustain no injury at each of these body regions. The frequency of severe injuries is low, often less than 10 % and concern head and thorax mainly. Finally, the frequency and severity of injuries decrease for belted occupants in newer cars compared to older cars, whatever body regions. The frequency of severe injuries decreased by almost 50 % in these newer cars.

How Safe is Vehicle Safety? The Contribution of Vehicle Technologies to the Reduction in Road Casualties in France from 2000 to 2010.

In France, over the last 10 years, road fatalities have decreased dramatically by 48%. This reduction is somewhat close to the target fixed by the European Commision in 2001 for the whole of Europe (-50 %). According to the French govnerment, 75% of this reduction was due to the implementation of automatic speed cameras on the roadsides from 2003 onwards. Yet, during this period, there was also a significantly increase in safety technology, new regulations in front and side impacts, and developments in Euro NCAP to improve passive safety in the vehicles. This paper set out to estimate the extent that vehicle safety technologies contributed to the road safety benefits over this decade. Using a combination of databases and fitment rates, the number of fatalities and hospitalized injuries saved in passenger car crashes was estimated for a number of safety technologies, individually and as a package including a 5 star EuroNCAP rating. The additional benefits from other public safety measures were also similarly estimated. The results showed that overall safety measures during this decade saved 240,676 fatalities + serious injuries, of which 173,663 were car occupants. Of these, 27,365 car occupants and 1,083 pedestrian savings could be attributed directly to vehicle safety improvements (11% overall). It was concluded that while public safety measures were responsible for the majority of the savings, enhanced vehicle safety technologies also made a significant improvement in the road toll in France during the last decade. As the take-up rate for these technologies improves, is expected to continue to provide even more benefits in the next 10-year period.

The evaluation of the safety benefits of combined passive and on-board active safety applications.

One of the objectives of the European TRACE project (TRaffic Accident Causation in Europe, 2006-2008) was to estimate the proportion of injury accidents that could be avoided and/or the proportion of injury accidents where the severity could be mitigated for on-the-market safety applications, if 100 % of the car fleet would be equipped with them. We have selected for evaluation the Electronic Stability Control (ESC) and the Emergency Brake Assist (EBA) applications. As for passive safety systems, recent cars are designed to offer overall safety protection. Car structure, load limiters, front airbags, side airbags, knee airbags, pretensioners, padding and non aggressive structures in the door panel, the dashboard, the windshield, the seats, and the head rest also contribute to applying more protection. The whole safety package is very difficult to evaluate separately, one element independently segmented from the others. We decided to consider evaluating the effectiveness of the whole passive safety package, This package,, for the sake of simplicity, was the number of stars awarded at the Euro NCAP testing. The challenges were to compare the effectiveness of some safety configuration SC I, with the effectiveness of a different safety configuration SC II. A safety configuration is understood as a package of safety functions. Ten comparisons have been carried out such as the evaluation of the safety benefit of a fifth star given that the car has four stars and an EBA. The main outcome of this analysis is that any addition of a passive or active safety function selected in this analysis is producing increased safety benefits. For example, if all cars were five stars fitted with EBA and ESC, instead of four stars without ESC and EBA, injury accidents would be reduced by 47.2% for severe injuries and 69.5% for fatal injuries.

Traumatic rupture of thoracic aorta in real-world motor vehicle crashes.

OBJECTIVE: Traumatic rupture of thoracic aorta (TRA) was reported in the literature to be a major cause of death in motor vehicle crashes. This study aims at evaluating the most relevant risk factors of TRA. It also aims at analyzing the types of TRA as a function of car crash conditions and rib cage fractures. METHODS: In-depth crash data collected from 1998 to 2006 as part of the Co-operative Crash Injury Study (CCIS) were retrospectively investigated to assess frontal, near-side, and far-side injury risks. This database includes 15,074 occupants with individual detailed autopsy reports. Multivariate statistical analyses were performed. The influence of the following variables on TRA occurrence was studied: gender and age of the involved occupant, ETS, compartment intrusion, and restraint system. Features of TRA and rib cage fractures were described thanks to autopsy data. RESULTS: Although TRA occurred in only 1.2% of all occupants, TRA victims accounted for 21.4% of all fatalities. The incidence of TRA was found twice higher in side impacts (2.4%) than in frontal ones (1.1%). TRA injury risk increased with ETS, intrusion, and age and decreased with the absence of intrusion regardless of the impact direction. It also decreased for belted occupants in frontal impacts. Except for the site of injury, the TRA features were similar whatever the crash conditions. The multiple ribs fractures were the most common injuries associated with TRA (79.1%) and TRA victims with uninjured or slightly injured (AIS 1) rib cage were significantly younger (p < 0.0001) than other TRA victims. Whatever the impact type, the TRA victims sustained mostly bilateral rib fractures (68%). Results also emphasized a close relationship between the principal direction of force and the body side with more fractured ribs. However, whatever the impact type, the aortic injury site or the side of the thorax, fractures concerned mainly the 2nd up to the 7th ribs of TRA victims. CONCLUSIONS: This study emphasized four main variables influencing the TRA occurrence: ETS, compartment intrusion, age, and seat belt use. The results suggested that the injury site may be different depending on the occupant or the impact type. However, the typical TRA, i.e., a partial or complete aorta transection within the peri-isthmic region, affected any occupant independently of age and impact type. The high frequency of bilateral rib cage fractures observed in TRA victims and the significant influence of intrusion on TRA occurrence emphasized that the aortic injury mechanism mainly involves a severe direct chest impact or compression.

Misuse of child restraint systems in crash situations - danger and possible consequences.

Based on real-world crash data and recent field studies, an ad-hoc group was set up in order to have a better comprehension of the effects of misuse of Child Restraint Systems (CRS) on child protection. A testing programme of 60 single misuse situations was conducted. Test results confirmed that, in frontal impact, children have higher risk of being injured on a number of different body regions when CRS's are misused. This work provides material for educational and training purposes to help parents understand that child restraints need to be correctly fitted in order to provide the level of protection they are designed for.

Is electronic stability program effective on French roads?

This paper proposes an evaluation of the effectiveness of the electronic stability program (ESP) in terms of reduction of injury accidents in France. The method consists of 3 steps: The identification, in the French National injury accident census, of accident-involved cars for which the determination of whether or not the car was fitted with ESP is possible. A sampler of 136 cars involved in injury accidents occurred in 2000, 2001, 2002 and 2003 was then selected. But we had to restrict the analysis to only 588 Renalut Laguna's. The identification of accident situations for which we can determine whether or not ESP is pertinent ( for example ESP is pertinent for loss of control accidents whilst it is not for cars pulling out of a junction). The calculation, via a logistic regression, of the relative risk of being involved in an ESP-pertinent accident for ESP equipped cars versus unequipped cars, divided by the relative risk of being involved in a non-ESP-pertinent accident for ESP equipped cars versus unequipped cars. This relative risk is assumed to be the best estimator of ESP effectiveness. The arguments for such a method, effectiveness indicator and implicit hypothesis are presented and discussed in the paper. Based on a few assumptions, ESP is proved to be likely effective. Currently, the relative risk of being involved in an ESP-pertinent accident for ESP-equipped cars is lower (-44%, although not statistically significant) than for other cars.

An evaluation of the effectiveness of the supervised driver-training system in France.

This paper presents an evaluation of the effectiveness of the French Apprentissage Anticipé de la Conduite (AAC), which is an optional initial driver training that seeks to reduce accident risk by novice drivers. The effectiveness of the AAC is estimated using a Case-Control study (521 Cases and 624 Controls) and the adjusted Odds ratio (AAC versus regular) from a multivariate logistic regression. Thirteen risk factors are retained as explanatory variables in the regression. An Odds ratio of 0.9 indicates a non-significant reduction in accident involvement of AAC participants in the two years following the acquisition of their driver's license. The discussion addresses the possible reasons underlying the lack of result, e.g. an absence of varied experience during the AAC period and possible undesirable effects under supervision such as a partial delegation of responsibility for driving tasks by the young driver to the supervisor. Our recommendations include that AAC be integrated into a gradual licensing scheme, and should focus on the gradual acquisition of various driving experiences (in terms of variety of driving situations).