Impact on the leg

A new device will be used to assess contact sensor technology that will be employed in active safety pedestrian systems.


After 12 months of  design and engineering work, the UK’s Transport Research Laboratory TRL, the wholly owned research arm of the Transport Research Foundation (TRF), has unveiled a new “biofidelic legform impactor” for testing and assessing contact sensor technology that will be employed in active safety pedestrian systems.


The new legform will enable vehicle and component manufacturers to accurately test and evaluate new pop-up bonnet systems which are designed to reduce head injury in the event of a pedestrian impact.


Based on research data, the legform resembles as far as is possible a human leg in terms of flesh density, whilst the bone material has properties that will enable fractures to occur should the loads upon the pedestrian leg be sufficient.  This has been achieved by using new materials which allow the device to closely imitate a human response.


The aim of the new impactor is to replicate a vehicle impact with a pedestrian in order to ensure the vehicle active safety system deploys to reduce the risk of injury to the pedestrian.  Conversely, the system needs to differentiate between pedestrians and other objects, such as animals or road debris, so that unwarranted deployments do not occur.


‘This new TRL biofidelic legform impactor will allow vehicle and component manufacturers to set accurate levels for active safety systems, preventing the bumper contact threshold being set too high, which could cause late deployment or even prevent the active system being deployed altogether,’ said James Manning,  the developer of the device.


The Active Safety Legform Impactor complements TRL’s existing pedestrian legform (WG17) which was not designed to test sensors but to evaluate the risk of lower leg injuries in a pedestrian impact.