Liability is assigned to the person who is negligent. The person potentially liable for an accident is the one who was driving and caused it due to negligence. Even if your grandfather carried the insurance on the car, he could not be liable for your actions, but his insurance company would be obligated to cover any damages. The potential negligence for your grandfather would be negligent entrustment. If you have a bad driving record or other issues that would alert him to know not to loan you the car he owns, he could be liable. But, in order to relieve your helpful grandfather of his worries, you should just change title on the car as soon as possible.
Answered on Jan 09th, 2014 at 12:26 PM