Posted on April 21, 2012 at 14:14You need to find someone qualified to answer/develop the solution. Random people on the internet should not be relied upon for life critical design parameters.
You need to know the initial speed/velocity, and the time/distance required to come to rest.
You might be able to get some number from local insurance/government labs about the forces in crashes from vehicle crash testing. The results from USA might not be applicable to vehicles in other markets with more lax safety requirements.
The G forces of hitting a concrete wall at speed are going to be very high, it's going to stop very quickly and the distance travelled will be the deformation of the vehicle. Hitting a pedestrian at similar speeds will have significantly less impact. Many accidents are considered insufficient to deploy an air bag, and depend on the direction of the impact.
http://www.hwycom.com/safetyCrashTest60.php
