Rust is never a good thing on a car. Though many simply see rust as a cosmetic issue or an eyesore, the problems go much deeper.
Swedish insurance company Folksam and the homeowner organization Villaägarnas Riksförbund published a video showing how much rust compromises a car's crashworthiness. The subject vehicle is a first-generation Mazda 6, a car that is known to rust out in salty road conditions. When crashed, the 6 shows numerous signs that rust has hurt its crashworthiness.
Specifically, the chassis rail separates from the floor, the footwell ruptures, and the sill gives out. Additionally, the seat mountings move and the crash dummy's head actually hits the B-pillar. All of these compromises show that the occupant driving would have a 20-percent higher risk of death. However, both Swedish firms actually expected worse results and were surprised the Mazda performed better than predicted.
A second video shows what better rust protection can do for crashworthiness. A fifth-generation Volkswagen Golf lines up for its own crash test, and despite some rust, it performs much better than the rust-infected Mazda.
According to the Swedish companies, the vehicles were not tested based on today's crash standards. Instead, both the Mazda and VW were judged based on the regulations in place when they first debuted in 2003. All the essential safety components still performed as they should, but the various compromised structures of the Mazda 6 shows that rust is nothing to mess around with when it comes to safety.