There are well over 275 million registered motor vehicles in the U.S. – a significant 100 million increase since 1990 – most of which are insured, which is no wonder considering that auto insurance is mandatory in most states. But there are always exceptions that prove the rule.
Not only do some states – for example, Virginia, New Hampshire, and Mississippi – not require car insurance or establish peculiar rules, but some drivers always show unimaginable negligence. As a result, around 13% of motorists in the U.S. are uninsured, and the percentage climbs to 20% and more in some states:
- Alabama – 21.8%.
- Florida – 23.5%.
- Oklahoma – 23.9%.
- Tennessee – 23.9%.
- New Mexico – 25.7%.
- Mississippi – 28%.
The United States can ‘boast’ one of the busiest roads in the world – over 227.5 million drivers operate 275 million vehicles – which, of course, results in higher and ever-growing accident and traffic-related fatalities rates. In 2020, over 38,500 people died on the road, and many more were injured. It goes without saying, no one wants to be one of them – as well as you don’t want to be financially unprotected when the disaster strikes.
Why Do You Need Uninsured Motorist Coverage (UM)?
While a typical case would still be that the at-fault driver’s liability insurance covers all the accident-related expenses, there may be – and the statistics above prove that – unwanted deviations from the rule.
If the at-fault driver
- doesn’t have insurance;
- doesn’t have enough coverage to cover all related expenses;
- have payment issues (if the insurer is unable to pay or denies the claim);
then you will likely have you pay tons of money out of pocket – dozens of thousands of dollars!
Luckily, though, there are two types of coverages that allow you to safeguard against uninsured drivers: uninsured motorist coverage (UM) and underinsured motorist coverage (UIM). If owned together, these coverages will help you cover both bodily injuries and property damage if the at-fault driver is unable to pay or cannot pay the full amount.
What Is UM Coverage?
Just like the title goes, uninsured motorist coverage helps you mitigate the risk of other drivers not having liability car insurance at all. Whether you live in a state with a high rate of uninsured drivers, or you want to find peace of mind and inner calm, not worrying about financial consequences of possible road accidents – and provided that the other coverages you may have are not enough – purchasing UM coverage may be a wise decision.
UM coverage will help you cover:
- Medical and funeral expenses.
- Lost income due to your disability to work resulting from the accident.
- Moral compensation.
What Is UIM Coverage?
Just like UM coverage, UIM coverage helps you mitigate the risks of – attention – other drivers not having enough liability insurance to compensate you for the damage done. UIM coverage will come in handy either if the other driver doesn’t have enough coverage or the liability limits of his or her coverage is less or equal to those of your UIM coverage.
Just like UM coverage, UIM will help you cover (up to the limits of the UIM policy) medical expenses, funeral expenses, lost income, as well as it will provide compensation for suffering and pain.
What Is the Difference Between UM and UIM Coverages?
The only difference is that UM coverage starts working instantly (because the at-fault driver is not covered whatsoever), whereas UIM coverage only covers the amount that is not covered by the other driver’s liability insurance. From the standpoint of the driver that carries UM or UIM, though, there’s no difference.
Types of UM and UIM Coverages
The good news is, not only can UM and UIM coverages help you protect against bodily injuries, but also the damage done to your car (property damage), if you choose the right types of coverage:
- UM (also known as UMBI) – bodily injuries.
- UMPD – damage to your car (in some states, also hit-and-runs).
- UIMBI – bodily injuries (the amount that exceeds the limit of the at-fault driver’s policy).
- UIMPD – damage to your car (the amount that exceeds the limit of the at-fault driver’s policy).
UM Coverage and Hit-And-Runs
If the driver escapes without leaving his or her contact information, then UM coverage may help in some states. Hit-and-runs are covered by both UMBI and UMPD, but UPMD may not be available in some states, or there may be a deductible. In the states where UMPD is unavailable – Colorado, California, Georgia, Louisiana, Ohio, and Illinois – you can use your collision coverage.
Coverage Stacking
In some states, you can stack your UMBI and UIMBI coverages to add the limits of these two policies and thereby get a higher overall limit. There are two types of stacking: vertical, or stacking multiple policies, and horizontal, or stacking the coverage limits of different vehicles within the same policy.
Example of vertical stacking: your own UMBI policy has a $10,000 coverage limit, and you’re also mentioned on your spouse’s insurance policy, which has a UMBI limit of $15,000. Then, at the expense of a higher premium, you can stack these two policies for a higher limit of $25,000.
Example of horizontal stacking: If you own three vehicles, while the first one has a coverage limit of, say, $5,000, the second one – $8,000, and the third one – $15,000, then, at the expense of a higher premium, you can stack those limits for a higher limit of $28,000.
- Both vertical and horizontal stackings are allowed in 22 states: Arkansas, Alabama, Colorado, Florida, Hawaii, Indiana, Kentucky, Montana, Missouri, Mississippi, New Mexico, New Hampshire, Nevada, Ohio, Pennsylvania, Rhode Island, South Carolina, Virginia, Vermont, Wyoming, Wisconsin, and West Virginia.
- Only vertical stacking is allowed in 10 states: Delaware, Georgia, North Carolina, New York, New Jersey, Oregon, Oklahoma, Texas, Tennessee, and Utah.
Is UM and UIM Obligatory In All States?
As being said, the rules vary by the state:
- UM or/and UMPD coverage is required in 22 states: Connecticut, Illinois, Kansas, Massachusetts, Missouri, Minnesota, Maryland, Maine, North Dakota, North Carolina, New York, New Jersey, New Hampshire, Nebraska, Oregon, South Dakota, South Carolina, Virginia, Vermont, Washington, Wisconsin, and West Virginia.
- UIMBI or/and UIMPD coverage is required in 14 states: Connecticut, Minnesota, Maryland, Massachusetts, Maine, New Jersey, Nebraska, North Dakota, North Carolina, Oregon, South Dakota, Virginia, Vermont, and Wisconsin.
Note: the mentioned states may require one to four types of coverage. Also, the minimum liability limits are different for different types of coverage.
Here’s an example so that you can understand how to read the coverage limits in different states:
- Coverage in Arizona: 15/30/10.
Now, 10 is the liability limit for one person injured in an accident, or bodily injury ($10,000), 30 is the liability limit for all people injured in an accident ($30,000), and 10 is the property damage coverage ($10,000).
UM Coverage in Florida
Here are Florida’s mandatory coverage limits:
- Bodily injury for one person/all people (passengers)/property damage – $10,000/$20,000/$10,000.
Besides, Florida has obligatory personal injury protection (PIP) coverage. PIP is mandatory in all no-fault states, which are the states in which a driver can file an insurance claim with his or her own insurance company regardless of whether he or she is responsible for the accident.
UM Coverage in California
Here are California’s mandatory coverage limits:
- Bodily injury for one person/all people/– $15,000/$30,000/$5,000.
For low-income drivers qualifies for California’s Low-Cost Auto Insurance Program:
- Bodily injury person/all people/property damage – $10,000/$20,000/$3,000
What if You Already Have Full Coverage?
You may or may not need UM coverage depending on:
- Your other insurance to cover bodily injuries. The purpose of UM coverage is to help you cover the medical bills that the in-fault driver cannot cover, which means, if your health insurance provides you with extensive coverage, you may not need UM coverage. But you may still need it if the deductible on your health insurance policy is high.
- Your other insurance to cover property damage. As you may know, collision insurance can be pretty effective in covering damage to your auto along with many other claims. Therefore, you have to proceed from whether you think your collision coverage is enough to safeguard you against financial troubles.
What Will Happen If You Don’t Have UM Coverage?
If you don’t own UM coverage, then you’re putting yourself at significant risk. Even in the safest states, at least 5% of drivers have no auto policy, so there’s always a possibility of the unexpected and unwanted happening. If you’re not covered by UM, you may have to face exorbitant medical or/and repair costs on your own.
How Much Does It Cost To Add UM and UIM Coverages To Your Insurance?
Since both UM and UIM coverages are extras, they are much cheaper than your regular bodily injury and property damage insurance. The actual price depends on the state, the insurer, and the specificities of the policy, but the general price range would be $10 to $80 a year.

Oleksandr is an expert in deep research. He covers insurance topics across four major insurance verticals – auto, health, life, and home insurance – while taking into account the legal landscape of the state in question. Come rain or shine, you can expect regular quality blogs and timely updates from Oleksandr.