| I’m not a crash test dummy, but…. If the object is completely fixed and effectively inelastic, the main determinant in survival is the distance over which the deceleration of the occupant occurs, assuming a lack of cabin intrusion. So the mass of the vehicle is ideally fixed in relation to its rigidity, and it’s not better to have less, or more, mass except as the ideal ratio to the rigidity of the vehicle. What you want is a vehicle that decelerates as slowly as possible over the greatest possible time/distance. A light vehicle that is very rigid is equally terrible as a heavy vehicle that is very rigid. What matters is how many millimeters it takes for each vehicle to come to a complete stop after colliding with the immovable object. There are a lot of combinations of vehicle mass and rigidity that meet the ideal here, and it is not sensible to assert that a massive or a lightweight vehicle will be ideal in this case. What you want is a vehicle that, at the speed of the collision, deforms the most completely and to the longest distance possible without incursions into the passenger compartment. Ideally, the vehicle would have a very long and well engineered crumple zone in front of the occupants. Here, assuming similar material engineering of the impact absorbing structure, length is king. All things being equal, a car with a stubby front profile will expose its occupants to twice the acceleration as one with a 2x longer hood. Still, the vehicle must have enough mass that the crumple zone is fully compressed at the speed of the collision. If it’s too light, it will decelerate before the impact absorbing distance if fully used. If it’s to heavy, it will still be moving when the crumple zone is fully exhausted, and either a sudden peak of acceleration or a cabin intrusion will occur when the passenger cage becomes involved in the deformation zone. I’m going to guess that on average, you’re still better off in a full sized SUV than In a more sensibly sized vehicle, hitting an unmovable object at speed. You say you have a background in vehicle safety, so maybe you know something I don’t. Please explain where I’m going wrong here? |