How an insurance company determines fault depends on state laws and the details of the accident.

State laws: Negligence

At-fault vs. no-fault state laws affect how auto insurance claims are paid out. In addition, how state laws define negligence affects how fault is determined and how claims are paid out.

Many times, a car accident may not be solely one driver's fault. An insurer may assign a percentage of blame to each party involved in the accident, based on the details of the accident.

For example, say a speeding driver rear-ends your car after you suddenly changed lanes. It may be determined that both of you are partially at fault for the accident. The other driver may be found 60 percent responsible and you may be 40 percent responsible.

The degree to which you're found negligent affects how you recoup your claim settlement after a car accident. And each state's laws vary when it comes to negligence.

Here are some terms you may encounter during a third-party car insurance claim, depending on where you live:

Comparative negligence

If your state uses pure comparative negligence, you may recoup accident-related expenses from the other driver based on their degree of responsibility for an accident.

For example, if the other driver is 60 percent at fault, their insurance company may pay up to 60 percent of your medical expenses and repair bills. You (or your insurance) would pay the remaining 40 percent.

The states that use pure comparative negligence are:

Alaska
Arizona
California
Florida
Kentucky
Louisiana

Mississippi
Missouri
New Mexico
New York
Rhode Island
Washington

Modified comparative negligence

If your state uses modified comparative negligence, you may not recoup expenses from the other driver if you're more than 50 or 51 percent at fault for an accident.

In those states, you would have to pay for your own medical expenses or repair bills, even if the other driver was partially at fault.

The states that use modified comparative negligence are:

Arkansas
Colorado
Connecticut
Delaware
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Maine
Massachusetts
Michigan
Minnesota
Montana
North Dakota

Nebraska
Nevada
New Hampshire
New Jersey
Ohio
Oklahoma
Oregon
Pennsylvania
South Carolina
Tennessee
Texas
Utah
Vermont
West Virginia
Wisconsin
Wyoming

Contributory negligence (Or pure negligence)

If your state uses contributory negligence, you may not recoup expenses if you bear any responsibility for an accident.

For instance, even if you were only 5 percent responsible for the accident, you would not get paid from the other party's insurance.

The states that use contributory negligence are:

Alabama
District of Columbia
Maryland

North Carolina
South Dakota
Virginia

Remember that recouping your costs after an accident depends on state laws and the car insurance coverage on your and the other driver's policies.

Accident details

Typically, when you file a claim, an insurance adjuster is assigned to your claim. The adjuster will gather details about the accident. This may include reviewing the police report, interviewing involved parties and assessing photos of damage. Based on their review, the adjuster works with the insurer to determine who's at fault for the accident.

Your car accident claim may be paid by your own insurer or by the other party's insurer, depending on who is at fault. Your insurer may pay part of your claim, based on the coverage you have on your own auto insurance policy. Or you may get a claim payment from the other driver's insurer.