The short answer
After a car crash, fault is generally determined by who was negligent, meaning they failed to act with reasonable care; an insurance adjuster will try to figure this out, but only a judge or jury can make the final decision.
Understanding Negligence
Negligence is when someone fails to act with the level of care that a reasonable person would have used in the same situation. This can be due to a person’s actions or because they failed to act when they had a duty to do so. The Legal Information Institute at Cornell Law School explains that to prove negligence, five elements may typically be required:
- A legal duty that the defendant owed to the plaintiff.
- The defendant’s breach, or breaking, of that duty.
- Harm to the plaintiff.
- The defendant’s actions being the direct cause (proximate cause) of the harm.
- The defendant’s actions being the actual cause (cause-in-fact) of the harm.
When a jury decides if someone’s actions were reasonable, they compare it to what a reasonable person would have done in the same situation. The North Carolina Department of Insurance states that an insurance adjuster investigating a crash will attempt to determine who is negligent or at fault. However, the Illinois Department of Insurance points out that only a judge or jury can ultimately decide who was at fault in an accident or how much another person owes you for your damages.
When More Than One Person Is at Fault
Sometimes, more than one person involved in a crash might be at fault. The Legal Information Institute at Cornell Law School explains that courts use a principle called comparative negligence to reduce the money an injured person can recover. This happens when the injured person was partially at fault due to their own negligence. The court may assign a percentage of fault to both the injured person and the defendant.
For example, the Legal Information Institute explains that if a court assigns 60% fault to the defendant and the injured person (plaintiff) was 40% at fault, the plaintiff may only recover 60% of the damages, rather than the full amount. The rules for how damages are awarded can vary greatly from state to state.
The Legal Information Institute describes two main types of comparative negligence:
- Pure Comparative Negligence: Under this rule, an injured person can still claim damages even if they were mostly at fault. For instance, they could claim damages for the 1% they are not at fault, even if they were 99% at fault.
- Modified Comparative Negligence: The Legal Information Institute states that the majority of states follow this rule. It has two common versions:
- 50 Percent Bar Rule: If the injured person is found to be 50% or more at fault, they may not recover any damages.
- 51 Percent Bar Rule: If the injured person is found to be 51% or more at fault, they may not recover any damages.
Contributory Negligence
Some states use a different rule called contributory negligence. The Legal Information Institute at Cornell Law School explains that under this rule, if an injured person contributed in any way to the incident, they cannot recover any damages. This applies even if they were found to be only 1% negligent. The Legal Information Institute states that only four states and the District of Columbia recognize the contributory negligence rule: Alabama, Maryland, North Carolina, and Virginia.
How States Apply Fault Rules
Laws about fault in car crashes vary by state. It is important to understand the specific rules in your state.
Illinois (Illinois Department of Insurance)
The Illinois Department of Insurance says that Illinois has a comparative negligence law. This means that more than one person can be at fault in an accident. Under this Illinois law, you can generally collect damages if you are 50.00% or less at fault for the accident, and the settlement can then be reduced by your percentage of fault. For example, if the other driver was 80% at fault and you were 20% at fault, you can collect for your damages, but the other driver’s insurance company might only offer to pay for 80% of your damages.
North Carolina (North Carolina Department of Insurance)
The North Carolina Department of Insurance explains that North Carolina has a contributory negligence law. This law bars a driver from collecting damages if determined to be partially at fault. In essence, in North Carolina, if you contribute to an accident, you may not be able to collect on a liability claim. Any disagreement over negligence may ultimately have to be resolved in a court of law.
Keeping Records
If you are involved in a car crash, keeping good records can be helpful. Here are some general actions you can take:
- Keep copies of all papers you receive or send.
- Write down the dates and times of any phone calls or meetings you have about the crash.
- Note the names of everyone you speak with.
- Write down what was said during your conversations.
What to Know About Hiring a Lawyer
If you decide to seek legal help, it is important to understand how lawyers typically charge for their services and how they are regulated. Lawyers in the United States are licensed by each state, and rules can vary.
Contingency Fees
The Legal Information Institute at Cornell Law School explains that in a contingent fee arrangement, lawyers receive a percentage of the money their client receives when they win or settle the case. Generally, the lawyer is paid only if the lawyer has successfully represented the client. The amount the lawyer receives often depends on the final result and on the phase of litigation in which the dispute settles. The Legal Information Institute says contingency fees are particularly common in personal injury cases, where the successful lawyer is awarded between 20% to 50% of the recovery amount.
Contingent Fee Agreements
ABA Model Rule 1.5© says a contingent fee agreement shall be in a writing signed by the client. It must state how the fee is determined, including the percentage the lawyer receives in the event of settlement, trial, or appeal. It must also state the expenses deducted from the recovery, and whether expenses are deducted before or after the fee is calculated. The agreement must also tell the client about expenses the client owes whether or not they win. At the end, the lawyer must give a written statement of the outcome.
The American Bar Association (ABA) Model Rules of Professional Conduct serve as models for the ethics rules of most U.S. jurisdictions. Each state adopts its own version, and the rules vary from state to state.
Lawyer Licensing
The National Conference of Bar Examiners explains that in the United States, lawyer admissions, professional conduct rules, and lawyer discipline are regulated jurisdiction by jurisdiction. A law license from one U.S. jurisdiction is not automatically transferable to or recognized by another. To provide legal services in a jurisdiction, a lawyer must be licensed by that jurisdiction or be otherwise authorized.
When to get legal help
If you have been in a car crash and have questions about fault, negligence, or your legal options, you may want to talk to a licensed attorney in your state. A lawyer can explain the specific laws that apply to your situation. You can also contact your state bar association or a legal aid office for more information about legal assistance.
Sources
- Legal Information Institute (Cornell Law School), Negligence (checked 2026-09-29)
- Legal Information Institute (Cornell Law School), Comparative negligence (checked 2026-09-29)
- Illinois Department of Insurance, Filing a Claim with Another Driver's Insurance Company (checked 2026-09-29)
- North Carolina Department of Insurance, After an Accident (checked 2026-09-29)
- Legal Information Institute (Cornell Law School), Contingency fee (checked 2026-09-29)
- American Bar Association, Model Rules of Professional Conduct, Rule 1.5: Fees (checked 2026-09-25)
- American Bar Association, Model Rules of Professional Conduct (checked 2026-09-25)
- National Conference of Bar Examiners, The Bar Examiner: Background Information About the U.S. System for Regulating Legal Services (checked 2026-09-25)
How this guide was made: it was written with the help of AI and automatically checked against the sources above before publishing. It is general legal information, not legal advice. Laws vary by state. For advice about your situation, talk to a licensed attorney in your state or a legal aid office.

