Pick two vehicles and send them head-on into each other. Watch what happens to the forces, and what happens to the accelerations.
Now a single car hits a fixed barrier at 35 mph — the standard frontal test. The car must stop. The person must stop too. You decide over what distance each of them does it.
Longer crumple zone means the car takes more time to stop. It also makes the car longer and costs more to build.
The car stopping is not the same as the person stopping. A restraint decides how far the person travels before they are stopped too.
This is what an accelerometer records. The area under the curve is the same every time — the car always goes from 35 mph to zero. All you are changing is whether that happens over a short, tall spike or a long, low hill.
A model is only useful if it behaves like the thing it represents. Compare your numbers to what engineers actually measure in these tests.
| Measured in real barrier tests | Value |
|---|---|
| Standard frontal test speed | 56 km/h (35 mph) |
| Typical peak deceleration, passenger car | ~25 g |
| Typical crash pulse duration | 65–130 ms |
| Peak deceleration spread across vehicle classes | ~11 g |
Figures from published analyses of NHTSA and Transport Canada full-frontal rigid barrier tests — one study analysed 1,094 crash tests using 2,795 accelerometers mounted in the occupant compartment. Your simulation is a simplified model built to match these conditions. It is not itself measured data.
You are recommending one design to a manufacturer. Defend it with your test log.
State the crumple zone length and restraint system, and give the peak g and duration it produced.
The car and the barrier always push on each other with equal and opposite forces. So what is your design actually changing, if it is not the size of the force?
Every design trades something. Which criterion was hardest to meet, and what did you sacrifice to meet it?