When you're involved in a car accident, having sufficient insurance coverage is important. When an uninsured or underinsured motorist crashes into your car, that's doubly true, because he or she doesn't have enough to cover your medical bills and property damage. "Stacking" your uninsured/underinsured motorist (UM/UIM) coverage can be a lifesaver — if your state allows it.

Stacking UM/UIM coverages means you are able to collect from more than one car insurance policy.

Stacking UM/UIM coverages means you are able to collect from more than one car insurance policy to receive full payment for your injuries and property damage. Not every state allows this, so check the chart at end of this story. Here's how you can stack your coverages.

Example 1
You own an auto insurance policy under which two or more cars are insured with UM/UIM coverage. When you're hit by an uninsured or underinsured driver, you collect the limits of your UM/UIM coverage under as many vehicles as necessary to receive full payment for your damages. For example, if you have a two-car policy with $50,000 worth of bodily injury UM/UIM coverage per person on each car, you can collect up to $100,000.

Example 2
You own more than one auto insurance policy with UM/UIM coverage. (The policies could be with the same insurer or two different insurers.) To collect all of the damages, you could make a claim under the UM/UIM coverage of each of the insurance policies you own. For example, if you have one policy with $50,000 worth of UM/UIM bodily injury coverage per person and another policy with $25,000 worth of UM/UIM bodily injury coverage, you can collect up to $75,000 for any injury you suffer as a result of a collision with an uninsured or underinsured motorist.

States split on stacking

Some state laws prohibit stacking of UM/UIM coverage, but many allow it in one form or another. As of September 2008, 29 states have statutes, rules or case law that either specifically allows stacking or does not address it. However, Robert Passmore, spokesperson for the Property Casualty Insurers Association of America, cautions that the details of your situation can effect your ability to stack coverage and that state laws, rules and codes change often as courts issue new decisions.

Also, in many of the states that allow stacking, auto insurers nonetheless permitted to insert policy language that prevents policyholders from stacking UM/UIM coverage. So while your state might permit stacking, if your policy expressly forbids it, you won't be able to stack your benefits.

Another wrinkle: The states that expressly forbid stacking of your UM/UIM benefits when you're the driver of a vehicle hit by an uninsured motorist might allow you to stack coverage if you are injured as a passenger in a vehicle or as a pedestrian that has been struck by an uninsured driver. For example, if you're a passenger in a car struck by an uninsured driver, you could collect benefits from the insurance policy of the driver of the car in which you are a passenger, as well as from your own policy if the driver's UM/UIM benefits were not enough to pay for your injuries.

There's also the possibility that you can collect from your own UM and UIM coverage more than once because many states regard these as separate coverages. For example, if you're a pedestrian who's hit by an uninsured driver, your UM coverage would kick in first and, theoretically, you could collect from your UIM coverage if your UM coverage is not enough to pay for your injuries.

However, the laws in each state vary widely with each situation and often depend on previous cases that have been decided in court. The bottom line is that there is often no easy answer to finding out if you can stack your UM/UIM benefits.

State	UM/UIM stacking allowed?	Citation
Alabama	Yes	§32-7-23 Alabama Revised Statutes
Alaska	No	§28.20.445 Alaska Statutes
Arizona	Yes	§20-259.1 Arizona Revised Statutes(1)
Arkansas	Yes	No citation(2)
California	No	§11580.2(q) California Insurance Code
Colorado	Yes	§10-4-609 Colorado Revised Statutes
Connecticut	No	§38A-336 Connecticut Insurance Code
Delaware	Yes	Title 18 §3902 Delaware Code (3)
Florida	Yes	§627.727 Florida Statutes(4)
Georgia	Yes	Georgia Insurance Law §33-7-11
Hawaii	Yes	§431:10c-301 Hawaii Statutes
Idaho	No	No citation(5)
Illinois	No	§215 ILCS 5/143a
Indiana	Yes	Indiana Code §27-7-5-5 (6)
Iowa	Yes	Iowa Code §516A.2
Kansas	No	Kansas Statute No. 40-284
Kentucky	Yes	No citation(7)
Louisiana	No	§22:1406 Louisiana Revised Statutes
Maine	No	No citation
Maryland	No	No citation(8)
Massachusetts	No	Ch. 175 §113L Massachusetts General Laws
Michigan	No	No citation
Minnesota	No	§65B.49 Minnesota Statutes
Mississippi	Yes	No citation(9)
Missouri	Yes	§379.203 Missouri Revised Statutes
Montana	Yes	§33-23-203 Montana Code
Nebraska	No	§44-6401 Nebraska Revised Statutes
Nevada	Yes	§687b.145 Nevada Revised Statutes(10)
New Hampshire	No	No citation(11)
New Jersey	Yes	§17:28-1.1 New Jersey Revised Statutes (12)
New Mexico	Yes	New Mexico Administrative Code Title 13 §12.3.17.6
New York	Yes	Ch. 35d §60-2.3e(iii) New York Administrative Rules (13)
North Carolina	Yes	§20-279.21 North Carolina Statutes (14)
North Dakota	No	§26.1-1-40-15.3 North Dakota Statutes
Ohio	Yes	§3937.18 Ohio Revised Statutes (15)
Oklahoma	No	No citation
Oregon	Yes	No citation(16)
Pennsylvania	Yes	Title 75 §1738 Pennsylvania Consolidated Statutes
Rhode Island	Yes	§27-7-2.1 Rhode Island Statutes
South Carolina	Yes	No citation(17)
South Dakota	No	§58-11-9 South Dakota Code
Tennessee	No	§56-7-1201 Tennessee Code
Texas	Yes	Texas Statutes 1952.101-170 (18)
Utah	Yes	Title 31A §22-305 Utah Insurance Code (19)
Vermont	Yes	No citation(20)
Virginia	Yes	§38.2-2206 Code of Virginia (21)
Washington	No	§48.22.030 Revised Code of Washington
West Virginia	Yes	No citation(22)
Wisconsin	Yes	§632.32 Wisconsin Revised Statutes (23)
Wyoming	No	No citation(24)
Statutes as of September 2008 Source: Property Casualty Insurers Association of America

(1) Insurers are permitted to add anti-stacking language to auto insurance policies.

(2) According to the Arkansas Department of Insurance, if the insurance policy language is ambiguous, courts allow stacking as long as the policyholder does not receive a windfall from the insurance settlement. However, courts in more recent cases have held that stacking benefits is not allowed, according to the department.

(3) Stacking is allowed but only among multiple policies.

(4) Insurers are permitted to add anti-stacking language to auto insurance policies.

(5) According to the Idaho Department of Insurance, courts have ruled stacking UM/UIM benefits is not permitted.

(6) Stacking is allowed but only within one policy.

(7) According to the Kentucky Department of Insurance, courts have ruled that stacking is permitted.

(8) Generally speaking, stacking of coverages under the same policy is not allowed, but stacking of coverages under different policies is permitted. However, courts in Maryland are divided on the matter, making their rulings based on the individual facts of the case.

(9) According to the Mississippi Department of Insurance, stacking is allowed based on Allstate Insurance Co. vs. Randall 753 F.2d 441 (5th Cir. 1985).

(10) Insurers that give a multicar discount are permitted to insert anti-stacking language into the insurance policy.

(11) Generally speaking, stacking benefits under the same policy is not permitted, but stacking benefits under different policies is allowed, according to the New Hampshire Department of Insurance.

(12) Stacking is allowed but only among multiple policies.

(13) Stacking is allowed but only among multiple policies.

(14) Stacking is allowed but only among multiple private passenger auto policies.

(15) Stacking is allowed but insurers are permitted to exclude it in the policy.

(16) Stacking is allowed but only among multiple policies.

(17) Stacking is allowed unless the policy has an anti-stacking clause that confirms with case law.

(18) Stacking is allowed but only among multiple policies.

(19) Stacking is allowed but only among multiple policies.

(20) According to the Vermont Department of Insurance, courts have ruled that stacking is permitted.

(21) Stacking is allowed but only among multiple policies.

(22) According to the West Virginia Insurance Commission, courts permit stacking of UM/UIM benefits, but if an insurer offers a multicar discount on an insurance policy, courts have ruled that the insurer can insert anti-stacking language into the policy.

(23) Stacking is allowed but insurers are permitted to exclude it in the policy.

(24) According to the Wyoming Department of Insurance, courts have ruled that state law does not require insurers to allow stacking of UM benefits. Courts have not ruled on the stacking of UIM benefits.