What is a side-impact protection system?

A side-impact protection system aims to shield a car's occupants from a side-on collision. While side-impact collisions are less common than head-on or rear-end collisions, they are typically more dangerous to the people inside the car that has been hit. A side-impact protection system typically uses a honeycomb structure in the doors to dissipate some of the force of the collision away from the occupants. Volvo was one of the first carmakers to feature a side-impact protection system, although most modern cars come with some sort of side protection.