Pedestrian Protection Systems: Issues, Survey, and Challenges <s> B. Passive Safety Systems Involving Vehicle Design <s> Collisions between pedestrians and road vehicles present a major challenge for public health, trauma medicine, and traffic safety professionals. More than a third of the 1.2 million people killed and the 10 million injured annually in road traffic crashes worldwide are pedestrians.1 Compared with injured vehicle occupants, pedestrians sustain more multisystem injuries, with concomitantly higher injury severity scores and mortality.2 Although a disproportionately large number of these crashes occur in developing and transitional countries, pedestrian casualties also represent a huge societal cost in industrialised nations. In Britain pedestrian injuries are more than twice as likely to be fatal as injuries to vehicle occupants3 and result in an average cost to society of £57 400, nearly twice that of injuries to vehicle occupants.4 ::: ::: #### Summary points ::: ::: Pedestrian-vehicle crashes are responsible for more than a third of all traffic related fatalities and injuries worldwide ::: ::: Lower limb trauma is the commonest pedestrian injury, while head injury is responsible for most pedestrian fatalities ::: ::: Standardised tests that simulate the most common pedestrian-vehicle crashes are being used to evaluate vehicle countermeasures to reduce pedestrian injury ::: ::: Energy absorbing components such as compliant bumpers, dynamically raised bonnets, and windscreen airbags are being developed for improved pedestrian protection ::: ::: Despite the size of the pedestrian injury problem, research to reduce traffic related injuries has concentrated almost exclusively on increasing the survival rates for vehicle occupants. Most attempts made to reduce pedestrian injuries have focused solely on isolation techniques such as pedestrian bridges, public education, and traffic regulations and have not included changes to vehicle design. The lack of effort devoted to vehicle modifications for pedestrian safety has stemmed primarily from a societal view that the injury caused by a large, rigid vehicle hitting a small, fragile pedestrian cannot be significantly reduced by alterations to the vehicle structure. Crash engineers, … <s> BIB001 </s> Pedestrian Protection Systems: Issues, Survey, and Challenges <s> B. Passive Safety Systems Involving Vehicle Design <s> At the Ford Forschungszentrum Aachen a finite element pedestrian humanoid model for use in pedestrian accident simulations was constructed that is capable of being used as vehicle engineering development tool. To further improve the understanding of the kinematics of pedestrian accidents and to optimise the computer simulation program it is necessary to collect a set of highly detailed real world data. At present that data is either unavailable, or not sufficiently accurate for this purpose. To meet these targets an interdisciplinary study has been established. In parallel a demonstrator vehicle has been build to show future technologies in pedestrian safety. <s> BIB002 </s> Pedestrian Protection Systems: Issues, Survey, and Challenges <s> B. Passive Safety Systems Involving Vehicle Design <s> Future legislation for pedestrian protection in Europe and Japan considers standardized test methods and test requirements relevant for a type approval. The first phase of legal introduction starts in 2005 and a more stringent second phase will follow in 2010. This paper consists of three main chapters. The chapter “Requirements” starts with a summary of the pedestrian protection-related requirements for head impact and its conflicting requirements for the vehicle handling and driving. The second chapter “Hood Concepts” discusses how the hood design could become compatible with the pedestrian protection requirements. Concepts for the hood design fulfilling both, the European as well as the Japanese requirements are described. The impact of the hood design parameters on the head impact performance are shown and different concept solutions are presented. The third chapter “Hood Hinge Concepts” examines the hinge performance for pedestrian protection in detail. The mounting points of the hood, such as hinges, latches and bumper stops, are the most critical points for head impact. Different hinge concepts and their impact on the head impact performance are shown. The influence of the hinge parameters on the acceleration curves and the HPC values is discussed and conclusions for the hinge design as well as for the vehicle structure are drawn. <s> BIB003
The design of the vehicle has great impact on the extent of injury that a pedestrian sustains in case of a collision. In BIB001 , the anatomy of a collision between a pedestrian and a vehicle is described in detail. In the case of small vehicles where the impact takes place below the pedestrian's center of gravity, the person falls and slides over the bumper, possibly with the head hitting the windshield or the windshield frame. Most of the injuries take place in lower limbs, whereas most of the fatal injuries are head injuries. In order to minimize the effect of these injuries, various collision-absorbing components such as compliant bumpers, pop-up bonnets, and windscreen airbags are suggested. Ford and Volvo research laboratories have developed the use a finite element model of a pedestrian to simulate accidents BIB002 . Such models help in predicting the effects of collision and in improving the vehicle design to minimize these effects. In BIB003 , the concepts of structural hood design are described to make it compatible with pedestrian safety. It shows the effect of hood and hinge design parameters on head impact and acceleration in order to optimize the parameters. The EU has recently mandated the incorporation of pedestrian safety systems in cars in two phases (2005 and 2010) . In [40] , an active hood has been designed, which automatically rises in case of collision with pedestrian, so that the surface that comes in contact with the head is deformable and flexible instead of hard and rigid. They have also developed a pair of airbags at the windshield pillar to prevent impact of windshield on the head. It is claimed that their pedestrian protection system can reduce risk of life-threatening injuries to 15% from nearly 100% for a collision at 40 km/h, which is enough to satisfy the EU requirement. According to the study in [20] , pedestrian airbags can reduce head injuries by 90% and upper body injuries by 50%. In India and other developing nations, collisions with heavy vehicles such as buses and trucks are the major cause of pedestrian fatalities. The differences between the kinematics of collision due to light and heavy vehicles are described in  . It is observed that collisions with heavy vehicles result in more serious chest, arm, and head injuries but less serious pelvic and leg injuries. In order to reduce these injuries, design changes for the fronts of bus and truck bodies are proposed. It is also proposed that truck bodies should be integrated with the chassis, and manufacturing should also be shifted from the local body builders to manufacturers where safety standards can be more effectively imposed.