In May 2013, the World Health Organization (WHO) reported that more than 270,000 pedestrians lost their lives on world roads each year, accounting for 22% of a total of 1.24 million road traffic deaths [1] . Despite the magnitude of the problem, most attempts to reduce pedestrian deaths have historically focused solely on education and traffic regulations. Since the 1970s, crash engineers have begun using design principles that have proven successful in protecting car occupants to develop vehicle design concepts that reduce the likelihood of injury to pedestrians in the event of a pedestrian car accident. This involves redesigning bumpers, hoods (bonnets), and windshields and pillars to absorb energy (softer) without compromising the car's structural integrity.
Video Pedestrian safety through vehicle design
Anatomy of pedestrian accident
Most pedestrian accidents involve moving cars (compared to buses and other vehicles with vertical hood/bonnet). In such accidents, pedestrians who are standing or walking are hit and accelerated to the speed of the car and then continue to the front when the car brakes stop. Although pedestrians were impacted twice, first by car and then by land, most of the fatal injuries occurred due to interaction with the car. Vehicle designers typically focus their attention on the understanding of car-pedestrian interactions, characterized by the following sequence of events: a vehicle bumper that first contacts the lower limbs of the pedestrian, the front edge of the hood touches the upper thigh or pelvis, and the head and torso top is hit by the top surface of the hood and/or windscreen [2] .
Maps Pedestrian safety through vehicle design
Reduce pedestrian injuries
Pedestrian death is mostly due to a traumatic brain injury resulting from a stubborn collision against a stiff hood or windscreen. In addition, although usually non-fatal, injury to the lower extremities (usually to the knee joint and long bone) is the most common cause of disability due to pedestrian accidents. The Frontal Protection System (FPS) is a device mounted on the front end of a vehicle to protect pedestrians and cyclists involved in front-end collisions with vehicles. The design of the car has been shown to have a major impact on the scope and severity of pedestrian injuries in car crashes.
Volvo has created an ADA for pedestrians and cycles with automatic braking designed to reduce pedestrian collision. With pedestrian injuries and casualties rising dramatically in the US by 2017, perhaps due to the increasingly disrupted driving with entertainment and communication systems in cars, pedestrian pedestrian safety support systems may become widespread.
Protect your head
The vessels of most vehicles are usually made of sheet metal, which is the corresponding energy absorbing structure and thus poses a relatively small threat. The most serious head injury occurs when there is not enough space between the hood and the rigid underlying machine components. A distance of approximately 10 cm is usually sufficient to allow the pedestrian head to have controlled decelerations and a significant reduction in risk of death [3] . Making space under the hood is not always easy as there are usually other design constraints, such as aerodynamics and styling. In some areas the hood is impossible. These include along the edges where the hood is installed and the cover, where the hood meets the windshield. Engineers have attempted to address this problem by using a formable stand, and by developing more ambitious solutions such as airbags that were activated during accidents and covering the rigid area of ​​the bonnet [4] . Some models, such as the CitroÃÆ'¡n C6 and Jaguar XK, feature a new bonnet pop-up design, which adds an additional 6.5 cm (2.5 ", C6) slot above the engine block if the bumper feels a punch.In 2012 and 2015, Volvo V40 and Land Rover Discovery Sport has an air bag under the hood that operates if the hood feels a bang. The airbag also covers the windshield pillars to provide better protection in all areas hit by the pedestrian head.
Protect limbs
Most of the limb injuries occur because of a direct blow from the bumper and the front edge of the hood. This results in contact of the femoral and tibia/fibula fractures and damage to the knee ligaments due to bending of the joints. Thus, efforts to reduce these injuries involve reducing peak contact power by making the bumpers softer and increasing the area of ​​contact and by limiting the number of bending knees by modifying the front end of the car's geometry. Computer simulations and experiments with corpses show that when the car has a lower bumper, the thighs and legs rotate together causing the knee to bend less and thus reduce the ligament injury probability. Deeper bumper profiles and structures beneath the bumper (such as an air dam) can also help limit foot rotation [5] .
Tram
Source of the article : Wikipedia
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