Effects of pre-impact swerving/steering on physical motion of the volunteer in the low-speed side-impact sled test

In order to simulate the actual pre-crash condition of a car that occurs when the drivers avoid an accident in an emergency situation, low-speed lateral sled tests on human volunteers were conducted using a sled-mounted rigid seat. It was observed that when the subject's muscles were initially relaxed, Sternoclaidomastoid and Rectus Abdominis started activation at around 100ms after the onset of acceleration and reached its maximum value at around 200-400ms. During this time period, most of the individual body region acceleration responses and restraint system reaction forces also peaked. Furthermore, the lateral flexion of head-neck-torso kinematics was strongly influenced by the muscle activity in the muscle tensed case and the posture-control effect of the lateral flexion due to the muscle tension was around 20-40%. This experiment indicates that muscles can control the occupant's behavior significantly during the low-speed impact, relating to the occupant's posture at the pre-crash phase.