Motorcyclist injuries: Analysis of German in-depth crash data to identify priorities for injury assessment and prevention.

Globally there are more than 350,000 PTW fatalities each year. Safety concepts to protect Powered Two-Wheeler (PTW) riders exist and are being developed further, but they need appropriate procedures and test tools (Anthropometric Test Devices (ATDs) for physical testing and Human Body Models (HBMs) for virtual testing) to direct and promote those developments. To aid further development of the tools, we aim to rank the frequency of specific injuries arising from the prevalent impact types, discuss how current ATDs and HBMs are equipped to assess these injuries, and suggest what further development should be prioritized. We analyzed a sample of injured riders from the German In-depth Accident Study (GIDAS) according to the Abbreviated Injury Scale (AIS) 2015 classification, using severity thresholds of at-least-moderate (AIS2+) and at-least-serious (AIS3+). PTW rider injuries were ranked by frequency for all crashes and also for sub-samples of specific impact types (impact with passenger cars, ground, and roadside furniture). The most frequent AIS3+ injuries were: femur fracture (17%), rib cage fracture (13%), lung injury (9%), tibia fracture (7%), and cerebrum injury (7%). In all impacts together and as for impacts with the road surface, injuries to the thorax were most frequent. In impacts with cars and road furniture, thorax injuries were also frequent, but outranked by lower extremity injuries. Considering both AIS2+ and AIS3+ injuries, the priorities for PTW rider safety interventions are: fracture of the rib cage, femur fracture, tibia fracture, radius fracture, cerebrum injury, and cerebral concussion. The ATD currently used most frequently, the Hybrid III, is unlikely to provide adequate rib fracture injury assessments, but HBMs are promising in this area. Rib injury assessment may also reasonably predict other injuries that were correlated or in proximity to rib fractures: clavicle, lung, and upper abdomen organ injury. Lower extremity, upper extremity, and head injuries are likely addressable to some extent with current ATDs while HBMs hold the promise of more detailed and mechanism-specific injury assessments. Both ATDs and HBMs need more validation for use in the PTW environment.

Assessment of Integrated Pedestrian Protection Systems with Autonomous Emergency Braking (AEB) and Passive Safety Components.

OBJECTIVE: Autonomous emergency braking (AEB) systems fitted to cars for pedestrians have been predicted to offer substantial benefit. On this basis, consumer rating programs-for example, the European New Car Assessment Programme (Euro NCAP)-are developing rating schemes to encourage fitment of these systems. One of the questions that needs to be answered to do this fully is how the assessment of the speed reduction offered by the AEB is integrated with the current assessment of the passive safety for mitigation of pedestrian injury. Ideally, this should be done on a benefit-related basis. The objective of this research was to develop a benefit-based methodology for assessment of integrated pedestrian protection systems with AEB and passive safety components. The method should include weighting procedures to ensure that it represents injury patterns from accident data and replicates an independently estimated benefit of AEB. METHODS: A methodology has been developed to calculate the expected societal cost of pedestrian injuries, assuming that all pedestrians in the target population (i.e., pedestrians impacted by the front of a passenger car) are impacted by the car being assessed, taking into account the impact speed reduction offered by the car's AEB (if fitted) and the passive safety protection offered by the car's frontal structure. For rating purposes, the cost for the assessed car is normalized by comparing it to the cost calculated for a reference car. The speed reductions measured in AEB tests are used to determine the speed at which each pedestrian in the target population will be impacted. Injury probabilities for each impact are then calculated using the results from Euro NCAP pedestrian impactor tests and injury risk curves. These injury probabilities are converted into cost using "harm"-type costs for the body regions tested. These costs are weighted and summed. Weighting factors were determined using accident data from Germany and Great Britain and an independently estimated AEB benefit. German and Great Britain versions of the methodology are available. The methodology was used to assess cars with good, average, and poor Euro NCAP pedestrian ratings, in combination with a current AEB system. The fitment of a hypothetical A-pillar airbag was also investigated. RESULTS: It was found that the decrease in casualty injury cost achieved by fitting an AEB system was approximately equivalent to that achieved by increasing the passive safety rating from poor to average. Because the assessment was influenced strongly by the level of head protection offered in the scuttle and windscreen area, a hypothetical A-pillar airbag showed high potential to reduce overall casualty cost. CONCLUSIONS: A benefit-based methodology for assessment of integrated pedestrian protection systems with AEB has been developed and tested. It uses input from AEB tests and Euro NCAP passive safety tests to give an integrated assessment of the system performance, which includes consideration of effects such as the change in head impact location caused by the impact speed reduction given by the AEB.

Evaluation of near-side oblique frontal impacts using THOR with SD3 shoulder.

OBJECTIVE: Within the EC Seventh Framework project THORAX, the Mod-Kit THOR was upgraded with a new thorax and shoulder. The aim of this study was to investigate whether the THOR ATD met a set of prerequisites to a greater extent than Hybrid III and by that measure whether the dummy could serve as a potential tool for future evaluation of serious head and chest injuries in near-side oblique frontal impacts. METHOD: A small-overlap/oblique sled system was used to reflect occupant forces observed in oblique frontal crashes. The head and thoracic response from THOR was evaluated for 3 combinations: belt only with no deformation of the driver's side door (configuration A), belt only in combination with a predeformed door (configuration B), and prepretensioning belt and driver airbag (PPT+DAB) in combination with a predeformed door (configuration C). To evaluate head injury risk, the head injury criterion (HIC) and brain injury criteria (BrIC) were used. For evaluation of the thoracic injury risk, 3 injury criteria proposed by the THORAX project were evaluated: Dmax, DcTHOR, and strain (dummy rib fractures). RESULTS: Unlike Hybrid III, the THOR with SD3 shoulder interacted with the side structure in a near-side oblique frontal impact. HIC values for the 3 test configurations corresponded to a 90% (A) and 100% (B and C) risk of Abbreviated Injury Scale (AIS) 2+ head injury, and BrIC values resulted in a 100% risk of AIS 2+ head injury in configurations A and B. In C the risk was reduced to 75%. The AIS 2+ thoracic injury risks based on Dmax were similar (14-18%) for all tests. Based on DcTHOR, AIS 2+ injury risk increased from 29 to 53% as the predeformed door side was introduced (A to B), and the risk increased, to 64%, as a PPT+DAB was added (C). Considering the AIS 2+ injury risk based on strain, tests in A resulted in an average of 3 dummy rib fractures (17%). Introducing the predeformed door (B) increased the average of dummy fractures to 5 (39%), but in C the average number of dummy rib fractures decreased to 4 (28%). CONCLUSIONS: THOR with an SD3 shoulder should be the preferred ATD rather than the Hybrid III for evaluating head and thorax injuries in oblique frontal impacts. Thoracic interaction with the predeformed door was not well captured by the 3D IR-Traccs; hence, use of deflection as an injury predictor in oblique loading is insufficient for evaluating injury risk in this load case. However, injury risk evaluation may be performed using the strain measurements, which characterize loading from seat belt and airbag as well as the lateral contribution of the structural impact in the loading condition used in this study.

Relationship between types of head injury and age of pedestrian.

This paper explores the relationship between age and the different types of head injury received by pedestrians in traffic accidents with cars. The analysis is based on information collected by hospitals in England, and is supported by in-depth case examples. The principle result is that the risk of intracranial injury increases with age, whilst the risk of fracture to the head or facial bones remains relatively constant. This agrees with previous findings for other groups of casualties, which have reported that that the decrease in brain size leads to an increase in the relative motion of the skull and brain in an impact, with a corresponding increase in the risk of traumatic brain injury. Intracranial injuries have also been found to place the greatest burden on hospitals, which may have implications on automotive design if prevention of these injuries is to be prioritised over fractures of the skull.