Pre-Crash and In-Crash Car Occupant Safety Assessment

Tens of millions are annually injured in Road Traffic Accidents (RTAs) worldwide, while the estimated number of RTA fatalities amounted to 1.35 million in 2016. In Europe, car occupants hold the largest share (48%) of fatalities among all road users. The high fatality and injury numbers motivate the work of enhancing road traffic safety. A holistic safety assessment approach, considering both the pre- and the in-crash phase of a crash, has the potential to enhance real-world occupant protection evaluation, as well as facilitate the development of effective countermeasures. In standardized car occupant safety assessments, occupant surrogates of standardized anthropometries are employed in standardized postures, with the seat adjusted to a single predefined position. The vehicle is then subjected to predefined crash configurations with meticulously described impact points and angles. In contrast, real-world traffic crashes involve occupants of different shapes and sizes, who adjust the position of the seat and their posture on the seat differently, and the vehicles are subjected to diverse crash configurations (multiple impact locations, impact directions, and speed combinations). The overall aim of this thesis is to develop and apply methods, spanning from the pre-crash to the in-crash phase, capable of evaluating and enhancing the real-world occupant protection of future vehicles.The introduction of crash-avoidance systems has the potential to alter the crash configurations that future vehicles will be exposed to. A method for predicting crash configurations has been developed in this thesis and applied to highway driving, and urban intersection crashes. Performing counterfactual simulations of digitized real-world crashes, with and without the addition of a conceptual Automatic Emergency Braking system, provides a prediction of the remaining crashes. The use of a novel crash configuration definition, along with a purpose-designed clustering method, facilitates the reduction of the number of predicted crash configurations without sacrificing coverage of the diverse real-world situations. Three predicted crash configurations, representative of urban intersection crashes, were further analyzed during the in-crash phase. A Human Body Model was positioned in a wide range of occupant postures identified from the literature. The findings suggest that the lower extremity postures had the largest overall influence on the lower extremities, pelvis, and whole-body responses for all crash configurations. In the evaluated side-impacts, leaning the torso in the coronal plane affected the torso and head kinematics by changing the interaction with the vehicle’s interior. Additionally, in far-side impacts supporting the occupant’s arm on the center console resulted in increased torso excursions. Moreover, the upper extremity responses were consistently sensitive to posture variations of all body regions

The influence of car passengers’ sitting postures in intersection crashes

Car passengers are frequently sitting in non-nominal postures and are able to perform a wide range of activities since they are not limited by tasks related to vehicle control, contrary to drivers. The anticipated introduction of Autonomous Driven vehicles could allow “drivers” to adopt similar postures and being involved in the same activities as passengers, allowing them a similar set of non-nominal postures. Therefore, the need to investigate the effects of non-nominal occupant sitting postures during relevant car crash events is becoming increasingly important. This study aims to investigate the effect of different postures of passengers in the front seat of a car on kinematic and kinetic responses during intersection crashes. A Human Body Model (HBM) was positioned in a numerical model of the front passenger seat of a midsize Sports Utility Vehicle (SUV) in a total of 35 postures, including variations to the lower and upper extremities, torso, and head postures. Three crash configurations, representative of predicted urban intersection crashes, were assessed in a simulation study; two side impacts, a near-side and a far-side, respectively, and a frontal impact. The occupant kinematics and internal loads were analyzed, and any deviation between the nominal and altered posture responses were quantified using cross-correlation of signals to highlight the most notable variations. Posture changes to the lower extremities had the largest overall influence on the lower extremities, pelvis, and whole-body responses for all crash configurations. In the frontal impact, crossing the legs allowed for the highest pelvis excursions and rotations, which affected the whole-body response the most. In the two side-impacts, leaning the torso in the coronal plane affected the torso and head kinematics by changing the interaction with the vehicle\u27s interior. Additionally, in far-side impacts supporting the upper extremity on the center console resulted in increased torso excursions. Moreover, the response of the upper extremities was consistently sensitive to posture variations of all body regions

Occupant Dynamics During Crash Avoidance Maneuvers

Technical Report FinalA test-track study was conducted to assess the effects of initial posture and position on the head motions of front-seat passengers in abrupt vehicle maneuvers. A pilot study with 12 participants was conducted in a sedan, a minivan, and a pickup truck to assess whether head excursions differed across vehicles. Each participant experienced two abrupt braking events, two lane changes, and turn-and-brake maneuvers. Peak vehicle accelerations were about 1 g and 0.7 g in the braking and lane-change events, respectively. Head position was tracked using a custom, semi-automated system that uses a single depth camera. Head center of gravity (CG) location was estimated from landmarks identified on a three-dimensional scan of the participant’s head and face. Forward head excursion was slightly smaller in the passenger car than in the other two vehicles. No explanation for this finding was apparent; the vehicle kinematics were similar. A larger study was then conducted using a passenger sedan and an SUV. A total of 90 men and women with a wide range of age and body size were assigned to test-condition blocks that addressed a variety of initial conditions. The factors investigated were seat position, foot placement, seat back recline angle, retractor locking, vehicle differences, and the effects of leaning inboard on the console armrest or leaning forward while reaching. Each participant experienced two braking events, a right-going lane change, a left-going lane change, and a turn-and-brake maneuver. The two vehicles performed similarly, and the acceleration profiles were similar to both the pilot study and a 2018 study at the same facility. Greater forward head excursion relative to the seat was observed when the seat was further rearward or reclined, or the feet were placed flat rather than resting on the heels. No difference in forward excursion was noted across vehicles. Forward leaning reduced forward head excursion during braking events, but the head position was more forward than when starting from a standard posture. Younger participants exhibited slightly larger forward excursions, but overall anthropometric effects were small. Forward lean produced much larger lateral excursions than the standard posture. Recline reduced lateral excursions, as did resting the feet on the heels rather than flat on the soles. Greater outboard excursion was observed in the SUV during the left lane change, possibly because greater space was available than in the sedan. Higher BMI and younger age were associated with slightly larger lateral excursions in some conditions, but anthropometric effects were small compared with the effects of test conditions. A functional regression analysis of head CG trajectories on the primary axes of motion was conducted. The results provide insight into the effects of test and occupant variables on head motion. Parametric corridors were developed that can be used to tune and validate computational models of occupant responses in pre-crash maneuvers. Overall, the results suggest that a wide range of occupant head locations can be produced by abrupt vehicle maneuvers. More research is needed to assess the robustness of occupant protection systems to this wide range of postures.National Highway Traffic Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/168421/1/UMTRI-2020-10 final.pdfDescription of UMTRI-2020-10 final.pdf : Technical Report Fina

Measuring the Effectiveness of Vietnam’s National Action Plan to Increase Helmet Use among Child Motorcycle Passengers in Three Major Cities.

Motorcyclists account for 75% of the estimated 22,000 fatalities caused by road injury each year in Vietnam. Helmets, widely worn by adult motorcyclists, are a cost-effective and proven intervention. Despite legislation mandating that children 6 years and above must wear helmets, child helmet use rates in Vietnam were low. In response, AIP Foundation leveraged evidence from its previous communications campaign to advocate Vietnam’s National Traffic Safety Committee (NTSC) to issue a National Child Helmet Action Plan for all 63 provinces during 2015. As part of the action plan, AIP Foundation adapted and expanded its communications campaign design from three target cities (Hanoi, Ho Chi Minh City, and Danang) to nationwide, focusing on 12 other provinces in Vietnam. The objective of this study was to evaluate the progress of the action plan toward its aim to a transformational increase in child helmet use in the 15 target cities and provinces by the end of 2015. Helmet observations at systematically sampled schools in the target provinces before and after the first phase of the action plan. The results from the final evaluation of the previous communications campaign are serving as the baseline for three target cities and post-observations will take place in April and November 2015. AIP Foundation measured baselines at the remaining 12 target provinces in March 2015 and will conduct a post-observation in November 2015. If funding is available, an additional post-observation will take place in all 15 target cities/provinces in November 2016 to assess the sustainability of the action plan. Average helmet wearing rates increased from 38% across the three target cities in March 2014 to 69% in April 2015. Hanoi experienced the greatest increase: from 23% in 2014 to 69% in 2015. In Danang, child helmet use increased from 37% to 75%, and in Ho Chi Minh City, the rate increased from 48% to 68%. An integrated campaign with national government leadership can bring about a substantial change in child helmet use. The adaptations applied to the action plan implementation have had a greater effect than the previous communications campaign

Vehicle and Traffic Safety

The book is devoted to contemporary issues regarding the safety of motor vehicles and road traffic. It presents the achievements of scientists, specialists, and industry representatives in the following selected areas of road transport safety and automotive engineering: active and passive vehicle safety, vehicle dynamics and stability, testing of vehicles (and their assemblies), including electric cars as well as autonomous vehicles. Selected issues from the area of accident analysis and reconstruction are discussed. The impact on road safety of aspects such as traffic control systems, road infrastructure, and human factors is also considered

Development of Guidance for a Vehicle Occupancy Rate Data Collection Program

118055Transportation planning practices increasingly require knowing the number of occupants per vehicle. Except for manual observations, Virginia has two data sources for obtaining occupancy: the American Community Survey and the National Household Travel Survey, neither of which provides corridor-specific values. This study developed an approach for estimating occupancy based on crash records data\u2014now feasible because Virginia routinely collects, for each crash, the total number of occupants regardless of injury status. This occupancy is not widely available because of privacy concerns but can be obtained through a special tabulation performed by VDOT\u2019s Traffic Engineering Division. Having crash data is not a panacea: as the area of interest shrinks from a district to a roadway segment, the likelihood that crashes alone provide a biased estimate of occupancy increases. Accordingly, the recommended approach for detecting occupancy contains two additional steps beyond extracting crash data: (1) at the jurisdiction level, test whether this bias exists by performing an eta-squared test; if appropriate, perform Type 1 bias correction by ensuring all occupancy groups (e.g., three occupants per vehicle) are synthesized in the crash data set; and (2) at the corridor level, perform Type 2 bias correction by building a correction model incorporating field observations. Yet bias is not necessarily a fatal flaw. At the corridor level, the mean average absolute difference between occupancy based on uncorrected crash data and occupancy collected from field observations was 0.06; use of the Type 2 bias correction model showed a difference of 0.05 between field observations and corrected data when the model was used on a set of data not used to build the model. At the jurisdiction level, the difference between uncorrected occupancies and Type 1 bias correction was never above 0.02 as long as at least 200 vehicles are observed in crashes. This method allows Virginia to estimate occupancies by time period, day type, and functional class. Crash data for VDOT\u2019s Hampton Roads District showed statistically significant differences in occupancies ranging from 1.18 to 1.30 (midweek vs. weekend); 1.15 to 1.22 (AM peak vs. off-peak); and 1.16 to 1.26 (variation among seven functional classes). The study recommends that VDOT establish an occupancy data collection program in one district based on two elements: (1) the extraction of occupancies from crash reports, and (2) an adjustment of these occupancies based on the two bias correction methods studied. These two recommendations need not preclude the possibility of using new technologies, some of which were examined in this study, but the approaches highlighted in this report have been successfully tested on a case study basis in Virginia

Commercial jet transport crashworthiness

The results of a study to identify areas of research and approaches that may result in improved occupant survivability and crashworthiness of transport aircraft are given. The study defines areas of structural crashworthiness for transport aircraft which might form the basis for a research program. A 10-year research and development program to improve the structural impact resistance of general aviation and commercial jet transport aircraft is planned. As part of this program parallel studies were conducted to review the accident experience of commercial transport aircraft, assess the accident performance of structural components and the status of impact resistance technology, and recommend areas of research and development for that 10-year plan. The results of that study are also given

The future of the urban street in the united states: visions of alternative mobilities in the twenty-first century

This dissertation is concerned with the present and future of urban streets in the United States. The goal is to document and analyze current visions, policies, and strategies related to the form and use of American urban streets. The dissertation examines current mobility trends and offers a framework for organizing visions of the future of urban streets, evaluating them through three lenses: safety, comfort, and delight: assessing physical conditions in accordance with livability standards toward sustainable development. At the same time, it demonstrates the way 12 scenarios (NACTO Blueprint for Autonomous Urbanism, Sidewalk Labs: Quayside Project, Public Square by FXCollaborative, AIANY Future Street, The National Complete Street Coalition, Vision Zero, Smart Columbus, Waymo by Alphabet, The Hyperloop, Tesla “Autopilot,” Ford City of Tomorrow, SOM City of Tomorrow) have intentionally or unintentionally influenced contemporary use of American urban streets. Ultimately, the study shows that while sustainable alternative mobilities continue to emerge, the dominance of the automobility system has led to a stagnation of sustainable urban street development in the United States

Scientific, Technical, and Forensic Evidence

Materials from the conference on Scientific, Technical, and Forensic Evidence held by UK/CLE in February 2002