system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Does acceleration matter in a car crash?

Scenario 1: A vehicle is simply maintaining speed and crashes at 40.

Scenario 2: A driver is accelerating fast in a high-performance vehicle from zero and crashes at 40.

Are they the same thing?
gpt
As far as the energy involved and the impact is concerned they are exactly the same. However the car will twist and pitch under acceleration and braking. So the crash might turn out differently. If you accelerates then it is possible for the crash structures of the cars to miss each other and the accelerating car climbs over the other car and can get launched into the air. This will often lead to rollovers and secondary collisions which can be far more fatal. But if the car is braking then the oppsoite might happen, the crash structure of the braking car might go under the crash structure on the other car. The car may therefore slide under the other car and the majority of the impact will be to the cabin of the car and not the front crash structure. This too is more fatal then if the crash structures hit each other. The dangers of these types of accidents is why modern cars and trucks comes with multiple bumbers at different heights that is designed to catch each other and prevent any one of the cars from sliding over the other. These bumpers are often covered by aerodynamic panels but you can often see how modern cars have a taller front then they did a few decades ago when they had more pointy front. You can also see this in trailers as they have gotten stronger and more numerous crash protection so cars will not be able to go under the trailer in the case of a crash.