Michigan has an Owner Liability Statute that makes the owner and negligent driver of a vehicle co-liable for any provable negligence/damages from a crash. Typically if one is not an owner of a vehicle that was negligently operated, and was not the negligent driver thereof, there would be no liability on that person (even if a co-insured of the vehicle). Insurer rate decisions are usually non-transparent and I'm not sure what effect a claim against 1 policy would have on another policy (theoretically none, but you'd best ask your insurer).
Answered on May 20th, 2016 at 10:02 AM