About half of the states in the country will allow you to stack auto insurance coverage. Stacking auto insurance coverage usually refers to increasing the limits for your uninsured motorists and underinsured motorist coverage policies. Usually, limits can be increased by insuring multiple cars; however, stacking limits can raise your insurance premium considerably.
For example, you own 2 vehicles with which you have car insurance on. Your uninsured motorist bodily injury coverage of is $100,000 per person and $300,000 per accident respectively. You have the same type of coverage on both vehicles, and if you choose to stack your uninsured motorists or underinsured motorist coverage, you would effectively double your limits to $200,000 per person and $600,000 per accident — regardless of which vehicle was involved in the accident.
Generally speaking, you can only stack coverage when you have policies on two or more vehicles, and stacking coverage would not be an option if you only own one vehicle. With a single car auto insurance policy, there is usually not any type of multiple coverage to stack.
While you generally cannot stack coverage if you only own one vehicle, there may be other ways to stack liability coverage for injuries to others. If you’re a homeowner, you may have the option of purchasing an umbrella liability policy which will also offer bodily injury coverage to people involved in an accident you are found to be at fault in. This can be considered stacking your liability coverage on your vehicle.