Raising the amount of auto insurance coverage above the minimum level won't result in substantially higher premiums for drivers.

It is both affordable and practical to go above and beyond the minimum legal requirements for liability coverage on a car insurance policy. Adding $10,000 of bodily injury liability (BIL) coverage costs nearly $18 per year on average across the 50 states.

Because of the low cost of adding more BIL coverage, a driver who is at fault in a car accident could pay the average cost of adding $10,000 in BIL 556 times before the expense equaled a $10,000 out-of-pocket payment after an accident. In this sense, purchasing more BIL coverage is worthwhile, especially in states where the cost of expanding coverage is even lower.

If a driver is determined to obtain complete coverage, the most effective add-on — particularly in states with high rates of uninsured drivers, such as Michigan, Louisiana, and Florida — is more uninsured motorist bodily injury (UMBI) coverage. This coverage costs just 0.01 percent of the median household income for an additional $10,000 of protection.

$10,000 in additional bodily injury and property damage liability coverage amounts to less than 1% of the median household income in every state

The average cost of adding $10,000 of liability car insurance coverage to a policy across the 50 states represents a small portion of the median income. Adding $10,000 in bodily injury liability and $10,000 in property damage liability equals 0.03 percent of median household income. Purchasing $10,000 more in both types of liability coverage in Louisiana, the most expensive state for adding coverage, amounts to only 0.15 percent of the median household income.

In terms of dollars, the average cost to add $10,000 in both types of liability coverage across the 50 states is $20.70. While less expensive, adding BIL is more expensive than purchasing larger amounts of property damage liability coverage. The average cost of adding $10,000 of BIL is $17.99, while property damage liability is only $2.71.

Adding coverage may be more expensive in some states than others. Louisiana is the most expensive state for this type of coverage, with a cost of $69.64 per $10,000 of BIL.

Depending on the state, purchasing more uninsured motorist bodily injury (UMBI) liability coverage may be a better value. UMBI pays for medical expenses incurred by uninsured drivers, those who flee the scene of an accident, and those who do not have enough liability insurance to cover the costs of a car accident. Nationally, the average cost of UMBI coverage is $7.79 per $10,000 of coverage.

In states with a high percentage of uninsured drivers, it's worthwhile to buy more UMBI to avoid a potentially costly encounter with someone who can't afford to pay for the medical expenses caused by a car accident. UMBI rates can be higher than the national average in states where many drivers are uninsured, such as Mississippi, Florida, and New Mexico. However, when compared to the cost of paying for these medical expenses out of pocket or pursuing legal action, the cost is much more affordable.

The amount of UMBI a driver carries is typically limited to the same amount or less than the amount of BIL contained in a policy. As a result, any increase in UMBI results in higher costs for both UMBI and BIL. The cost of adding bodily injury, property damage, and UMBI is higher in the states with the most uninsured drivers, but it is still less than 0.1 percent of median income in these states.

Washington and District of Columbia excluded due to technical limitations

Increasing a deductible from $500 to $1,000 may not elicit significant savings — depending on the state

Insurance against physical damage to your vehicle is more expensive than liability coverage. The cost of comprehensive and collision coverage is likely to be a significant portion of the overall cost of insurance, depending on the deductible.

Raising the deductibles for comprehensive and collision coverage is an effective way to reduce overall car insurance costs. A $500 comprehensive deductible results in an average cost of $323 per policy across the 50 states, while a $1,000 deductible results in a cost of $238. Collision coverage, on the other hand, costs $827 with a $500 deductible and $653 with a $1,000 deductible.

 This means that for every $100 increase in the deductible, drivers with comprehensive coverage will see an increase in the cost of their policies of $16.90. It's much more expensive for collision — $34.91, on average. However, when average payouts are considered, it is worthwhile to carry both types of coverage.

 In 2019, the average cost of a collision claim was $3,750. This means that adding collision coverage with a $500 deductible costs five times less than the typical out-of-pocket cost for repairing this type of damage without collision coverage. A $1,000 deductible reduces the cost of coverage to six times that of a typical out-of-pocket expense.

While comprehensive coverage is less expensive, it still saves its users roughly the same amount in terms of potential accidents as collision coverage. The cost of comprehensive coverage with a $500 deductible is six times less than the average claim settlement of $1,780, while coverage with a $1,000 deductible is seven times less.

In general, because the costs of comprehensive and collision coverage represent similar percentages of the average claim payout, they're both equally valuable additions to a standard policy — though the best deductible level varies by state.

States ordered by the most prominent drop in collision costs after increasing the deductible from $500 to $1,000.

Massachusetts is the best state in which to increase one's collision deductible. Drivers who increase their deductibles can save up to 32% on their insurance premiums. Collision coverage premiums in Massachusetts are among the lowest in the country, at $574. In contrast, in states such as Tennessee, where the cost only decreases by 10% afterward, the decision to raise one's deductible is less important. In these states, keeping a lower deductible allows drivers to make smaller claims while still paying relatively low rates.

What about adding other forms of coverage?

Most people will find it worthwhile to purchase additional types of car insurance that aren't included in the cost of a full coverage policy. Gap coverage (for leased or loaned vehicles) and towing services, in particular, are inexpensive ways to increase the coverage of one's insurance policy.

In an analysis of all 50 states, LowCostInsurance discovered that the average cost of adding unlimited towing coverage only increases car insurance costs by $16. Similarly, drivers who finance their vehicles with a loan can get gap insurance for $63 per policy, which covers the value owed on a lease or loan after a total loss. Both types of coverage are effective methods of avoiding large out-of-pocket expenses if one's vehicle is totaled.

Towing coverage is cheapest in Maine, where services cost an average of $9 per year. Gap insurance is also the least expensive in Maine, where it costs $29.

Table is ordered by the lowest cost of towing services.

Keeping PIP to a minimum, even while adding more liability coverage, is an effective way to lower the overall cost of car insurance

Increasing the amount of liability coverage above the statewide required limits necessitates an increase in coverage costs. However, each $10,000 increase in BIL coverage costs an average of $17.99, or 0.03 percent of the median household income.

Personal injury protection (PIP), which is required in 16 states and available for purchase in a few others, has the greatest impact on car insurance costs. The average cost of PIP in the ten states where it is required and data is available is $7.01 per $1,000 of coverage. While this figure is lower than the average BIL rate of increase, it is a greater financial burden in the majority of cases than BIL.

One reason for this is that the options for customizing PIP coverage are limited. Companies frequently offer it in accordance with statewide laws and regulations, and users seeking more coverage may be locked into higher rates.

For example, in Michigan, where car insurance is already expensive, drivers must carry a minimum of $250,000 in PIP coverage, but if they want more protection, they can increase the limit to $500,000 or choose unlimited coverage. Although the cost of PIP in Michigan is only 44 cents per $1,000, multiplying that by 250 results in a significant cost increase.

Depending on a driver's risk tolerance, it's a good idea to consider the financial cost of purchasing more PIP than is required, especially since it may be more cost effective to get more BIL and UMBI coverage instead.

Methodology

 LowCostInsurance collected two sets of 12-month, full coverage car insurance rates from across the country and then calculated the cost per dollar of increasing one's insurance limits. The researchers collected two sets of quotes with the following constraints:

 Allstate only allowed researchers to gather rates in most cases for $100,000/$300,000 of bodily injury liability protection instead of $100,000/$200,000.

 Researchers also gathered personal injury protection quotes in states where they were available, with the exception of Massachusetts, Minnesota, New Jersey, New York, and Pennsylvania, where technical difficulties arose. In each case, researchers gathered quotes that met the bare minimum and calculated the cost of increasing each by $1,000.

 The insurance rate data used in LowCostInsurance analysis came from Quadrant Information Services. These rates were obtained publicly from insurer filings and should only be used for comparison purposes, as your quotes may differ.