A series of tests are carried out to replicateaccidents involving child and adult pedestrians where impacts occur at 40kph (25mph). Impact sites are then assessed and the protection offered is rated as fair, marginal or poor.
It is very difficult to assess pedestrian protection using a full dummy. Although it is possible to control the point of impact of the bumper against the pedestrian’s leg, it is impossible to control where the dummy’s head will subsequently strike. To overcome this problem, individual component tests are used. A Legform test assesses the protection afforded to the lower leg by the bumper, an Upper Legform assesses the leading edge of the bonnet and child and adult Headforms are used to assess the bonnet top area.
|Lower Leg Form
||Upper Leg Form
Protection can be improved with pedestrian friendly bumpers, which deform when they hit a pedestrian’s leg. Protection is improved if the leg is impacted low down, away from the knee, and if the forces are spread over a longer length of leg. For the leading edge of the bonnet, improvements can result from the removal of unnecessarily stiff structures. To protect the head, the bonnet top area needs to be able to deflect. It is important that sufficient clearance is provided above the stiff structures beneath, which would stop this deflection. On some types of vehicles the packaging in the engine compartment can be altered to create this clearance, other vehicles will use technology, such as deployable protection systems, to achieve the space.
Deployable protection systems
A deployable or ‘pop-up’ bonnet is designed to lift in a crash involving a pedestrian to create more space to absorb the head impact energy and reduce the severity of the injury. Most systems on the market comprise contact sensors in the front bumper area of the car in combination with bonnet lifters such as springs, a pyrotechnic charge or an external airbag. On vehicles equipped with a deployable protection system, Euro NCAP carries out headform tests on the fully deployed or deploying bonnet if the manufacturers can show that the sensors are able to trigger the system for the pedestrian stature which is hardest to detect (often a young child) and that the system response time is fast enough to provide full protection before the head would contact the bonnet. In addition, the design must provide adequate levels of protection just below trigger thresholds and at higher speeds.