GAP insurance is a type of coverage designed to protect you under specific circumstances: when you owe more on a financed or leased car than its current market worth. It bridges the "gap" between what you owe on the car loan and what the car is worth at the time of a total loss event.
If you’re thinking about what to do when your car is totaled, and you still owe money for it with no insurance in place, unfortunately, GAP won’t help. The thing is that this insurance type offers additional settlement and won’t be issued unless you have comprehensive auto insurance.