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From an automotive safety occupant protection standpoint, effective occupant restraint requires a system capable of providing non-injurious occupant ride down of anticipated crash forces. This is not only the case for frontal collisions, where occupant restraint is provided primarily by seatbelts and airbags, but is also critical for other crash modes such as side impacts, rear impacts, rollovers, as well as multiple impact events. In the rear impact crash mode, occupant restraint is provided primarily by the seatbacks and to some extent the seatbelts. Foundationally, therefore, what becomes fundamental to the seatback's role in rear occupant protection is its ability to contain the occupant within the seat, preventing occupant ramping, as well as preventing the seat's, and/or its occupant's, dangerous intrusion into the rear occupant's survival space where contact with rear compartment components and/ or rear seated occupants can present a significant injury risk. An analysis is presented of a series of rear impact sled testing conducted by the authors that evaluates the timing, position and extent of the front seatback's reward displacement toward and into the rear occupant compartment as well as consideration of the front seat occupant' ramping potential and its injury potential relative to the rear compartment. Additionally, three other series of testing are presented which assess various seat designs occupant retention capabilities. Lastly, a matched-pair comparison test series is presented which evaluates occupant motion in rear impact with and without use of a typical vehicle body mounted 3-point seatbelt. Discussion of restraint system performance observed in all the testing is included along with ATD biofidelity and thigh-gap considerations. The data collected and presented includes accelerometer instrumentation and high speed video analysis.
Although the bus belongs to the safest traffic means, single accidents can be particularly severe and concern many passengers. Especially in case of fires a high number of injured and killed persons can be the outcome. Fire safety of buses therefore is of high importance. With the increase of plastic materials as a material for the interior equipment of buses and coaches due to their good mechanical properties combined with low weight, the question arises whether the safety level has decreased in case of a fire during the last years " also compared to other means of transport. Because of the combustible plastics and their ability to release a high amount of heat the main fire load in buses is no longer the fuel but the plastic materials which are also often easy to ignite. Besides the flammability of the equipments, also the production of smoke, the smoke development and propagation as well as its toxicity are of interest. That counts for the passengers as well as for the test methods and its limit values. The severe fire in Germany near Hanover in 2008 with 20 fatalities showed how disastrous such fires can be. For those reasons several research projects were initiated on behalf of the German Federal Highway Research Institute. At the one hand the fire behaviour of coach interiors was examined in general focusing on fire propagation as well as fire detection and signalling. As result, recommendations with regard to early fire detection systems for the engine compartments and onboard extinguishing equipment were elaborated. On the other hand research was carried out to examine heat release, smoke, smoke propagation and its toxicity due to burning bus interior materials. In this project small and real scale experiments on material specimens, interior parts and vehicles were performed. Trains and buses often have very similar operation conditions. Consequently, bus interior material was tested according to the regulations for rail vehicles, i.e. DIN EN 45545 as well as DIN 5510. None of the tested bus interior materials would have been allowed to use in a train. The fire safety regulations for bus materials are on a low level compared to other transport sectors, i.e. railway, ship and aircraft. Also numerical investigations with the Fire Dynamics Simulator (FDS) were performed. The very rapid fire development during the severe bus fire from 2008 could be predicted with the numerical model. The model was then used to investigate the influence of different materials, ventilation conditions and ignition sources. The bus materials contribute significantly to a very rapid fire development in bus fires. Especially, the flammable ceiling and the passenger seats were identified to be key issues of the fire propagation in a bus and can be explained by the rapid fire spread along the ceiling and the high fire load of passenger seats. As conclusion of the project effective and economically reasonable fire safety requirements for interiors of buses are recommended which would improve the current situation. Proposals for amendments of current requirements are recommended including the specification of appropriate limit values. In particular, it is taken into consideration which reasonable fire safety standards from other transport sectors, especially the rail sector, should be transferred to buses
Past European collaborative research involving government bodies, vehicle manufacturers and test laboratories has resulted in a prototype barrier face called the Advanced European Mobile Deformable Barrier (AE-MDB) for use in a new side impact test procedure . This procedure offers a better representation of the current accident situation and, in particular, the barrier concept is a better reflection of front-end stiffness seen in today- passenger car fleet compared to that of the current legislative barrier face. Based on the preliminary performance corridors of the prototype AE-MDB, a refined AE-MDB specification has been developed. A programme of barrier to load cell wall testing was undertaken to complete and standardise the AE-MDB specification. Barrier faces were supplied by the four leading manufacturers to demonstrate that the specification could be met by all. This paper includes background, specification and proof of compliance.
In road traffic accidents, a car-seat and its occupant can be subjected to various crash pulses in the case of a rear impact. This study investigates the influence of crash pulse shape on seat-occupant response and evaluates the corresponding risk of whiplash injury. For this purpose, a rigorously validated seat-occupant system model is used to study different carseat designs and crash pulses. Two different car-seat concepts are also presented which can effectively mitigate whiplash injury for a wide range of crash severity. It is shown that for crash pulses of similar severity, the level of whiplash-risk depends strongly on the combined effects of seat design and crash pulse shape.
Although the statistics show a decreasing rate of child injuries and fatalities in German road accidents more efforts can be made to protect children in cars e.g. by developing appropriate child restraint systems. An important part in of this work can be achieved with the help of crash tests using child dummies. However these crash tests cannot completely reflect the situation of real world crashes as factors like children moving out of the optimal position or children incorrectly fastened by their parents are difficult to predict. Therefore this study gives an overview over the current accident and injury situation of child occupants in cars in German road accidents.
Females sustain Cervical Spine Distortion injury (CSD) more often than males. Most work dealing with the biomechanics background (e.g. injury mechanism/criteria) as well as the application in seat design/testing, focuses on the occupant model of an average male. Therefore the EU-Project ADSEAT (Adaptive Seat to Reduce Neck Injuries for Female and Male Occupants) is aimed at adding a female model for gender balanced research of CSD and improving seat design. An extensive literature review, searching for risk factors and injury criteria for males and females, was accompanied by the evaluation of different databases containing CSD cases. The database evaluations suggests that an anthropometry quite close to the 50%ile female anthropometry as known from crash test dummy design is appropriate. The results presented here form the basis for the future development of a computational female model and the improvement of seat design for better protection of both males and females in the frame of the ADSEAT-Project.
The so-called "seat-belt injuries" or "seat-belt syndromes", described as 2-point seat-belt injuries, contain heavy inflection injuries of the lumbal spinal column, combined with heavy abdominal injuries as rupture of the upper intestinal bold or heavy injuries of the upper entrails. With "playing" children in the font of the car, with inappropriate plant of 3-point belts, identical injuries can occur.
Nowadays airbags are part of the standard equipment in almost all new cars. While airbags are saving an increasing number of people from severe injuries and death in moderate and high speed crashes, they do not completely prevent dashboard injuries. The most common mechanism in dashboard injuries is a posteriorly directed force to the proximal tibia with the knee flexed. This may occur during a motor vehicle frontal impact accident when a knee of the driver or the front-seat passenger strikes the dashboard. The posterior force can be combined with a abducting or rotational force leading to concomitant lateral or posterolateral injury. Car and airbag manufacturers therefore develop special inflatable systems to reduce the impact force in dashboard injuries. Every new inflatable system, however, has to be evaluated in out of position situations in which the system might cause injuries to certain body areas. Therefore, we investigated a new kneebag system in different critical seating positions of post mortem test subjects (PMTS). The tested knee airbag module is a folded airbag (18 litre volume) which is installed below the lower section of the instrument panel of a passenger car. Using four PMTS (2 male, 2 female, age 36"67) the following positions were tested: normal seating position, knee flexed >90 degrees and knee flexed <60 degrees in static deployment tests with direct contact. In addition a dynamic test (48.8kph, AAMA-pulse) was carried out with the PMTS belted in a normal seating position. The inflation phase and the impact of the system on the knee/lower leg were analysed by high speed videos. After the test the lower legs of the PMTS were examined by Xray and autopsy. All soft tissue injuries and bone fractures were recorded. All the tests could be evaluated. Except some superficial skin lesions in the impact area no fracture of the bones around the knee and no knee ligament and tendon injuries were observed. Neither video analysis nor autopsy of the PMTS showed any critical contact injuries caused by the inflation process of the bag. Therefore, it can be concluded that in the tested seating positions which are the most critical for the knee area the knee bag system is safe.
Sedan type vehicles in which adult rear seat passengers were present and which were involved in frontal collisions were investigated, and the influence of unbelted rear seat passengers on the injuries of front seat occupants was studied. Unbelted rear seat passengers move forward during impact. It was observed that there were not only cases in which front seat occupants sustained injuries caused by direct contact with rear seat passengers, but also cases where front seat occupants received severe injuries due to additional force from rear seat passengers, either impacting directly or indirectly as a result of deformation of the front seat. Severe injuries of front seat occupants were observed in the latter cases. This research validates the importance of seat-belt use for rear seat passengers, not only to protect themselves but also to mitigate injuries of front seat occupants.
Since the compulsory use of child restraints for children up to 5 years of age was introduced in 2000, restraint use among younger children has increased significantly. However, the observed rate of child restraint use plateaus at around 50%, and apparently little spillover effect has been found for older children who are not covered by the law. This report examines the restraint use patterns for children who were injured in cars in relation to driver and child passenger characteristics. Univariate and multivariate analyses were conducted to describe the association between the outcome measure (the proper use of restraints for children) and relevant variables. Better ways for parents and caregivers to improve the use of restraints for children are also discussed.