The Influence of Vehicle Low Impact Velocity over the Helmet Airbag Deployment and Cyclist Injuries

Abstract

The aim of this paper is to assess the influence of the vehicle impact velocity over the deployment of cyclist helmet airbags, as well as the resulting head and neck injury severity. Two crash-tests were carried out in a longitudinal impact configuration (bicycle hit from the rear) using the same vehicle-bicycle-dummy assembly: Test 1 (6.86 m/s impact velocity, 0.4 m offset) and Test 2 (11.1 m/s impact velocity, 0.4 m offset). The head and thorax of the dummy cyclist were instrumented with tri-axial accelerometers. An activated helmet airbag was positioned onto the neck of the dummy for both tests, which did not deploy during the Test 1, but deployed during Test 2 due to the higher head acceleration. A discussion about the causes of the airbag non-deployment during Test 1 is provided. HIC and NIC values were calculated using the recorded head and thorax accelerations and are presented in this paper. Although skull fracture risks were neglectable for Test 1, the NIC value obtained was 56\% higher (61 m(2)/s(2)) than the NIC value obtained for Test 2 (41 m(2)/s(2)), which shows that helmet airbags do have a potential in mitigating cyclist neck injuries.