A vehicle collision is commonly described as being made up of 3 distinct parts.

The three parts of a vehicle collision

  1. The vehicle collision
    The vehicle itself hits something (another car, a wall, a tree, a pedestrian, etc.), and its forward motion rapidly slows or stops.

Metal crumples, glass breaks, and the car’s structure absorbs as much energy as possible.

  1. The human collision
    Even after the car stops, the people inside keep moving at the original speed until they hit something: seat belt, airbag, steering wheel, dashboard, or window.

This is why seat belts and airbags are so critical—they spread out forces and slow the body more gently.

  1. The internal collision
    Inside the body, organs (like the brain, heart, and lungs) keep moving and can collide with bones or other organs, causing internal injuries such as brain trauma, organ bruising, or internal bleeding.

You can imagine it as three “waves” of impact: first the car , then the person , then the organs —all happening in fractions of a second.

Why this concept is often taught

  • It helps explain why low-looking damage can still mean serious injury (because the dangerous collisions happen inside).
  • It’s widely used by injury lawyers, safety educators, and driver’s ed materials to teach the importance of seat belts, airbags, and modern crash protection.

TL;DR: When people ask “how many distinct parts is a vehicle collision made up of?”, the standard answer is 3: the vehicle collision, the human collision, and the internal collision.

Information gathered from public forums or data available on the internet and portrayed here.