Illinois Comparative Negligence Law Explained [2026 Guide]

How Illinois Comparative Negligence Law Affects a Personal Injury Case

Illinois follows a modified comparative negligence rule under 735 ILCS 5/2-1116.

In cases involving bodily injury, death, or property damage based on negligence, a plaintiff can generally recover damages as long as the plaintiff’s contributory negligence is not more than 50% of the cause of the injury.

When the injured person shares fault, the total amount of recoverable damages is reduced in proportion to that percentage.

For example, if a verdict awards $200,000 after a car accident and the injured person is found 30% at fault, the recovery would generally be reduced to $140,000.

Shared fault can arise from disputed conduct on both sides.

In a crash involving a left-hand turn, for example, one driver might be accused of failing to yield while the other is accused of running a red light or speeding.

A judge or jury may assign each party a percentage based on the evidence and determine how that allocation affects the final award.

The key dividing line in Illinois is 50% versus 51%:

• 50% or less at fault: The injured person may still recover, but the award is reduced by their percentage of responsibility.
• Exactly 50% at fault: Recovery is still permitted, but the award is reduced by half.
• More than 50% at fault: The injured person is generally barred from recovering damages.

In Illinois, this 51% bar rule is critical to personal injury recovery because even a small change in the assigned percentage can determine whether compensation remains available.

The statute also now provides that contributory fault cannot be attributed to a plaintiff bringing a personal injury claim based on childhood sexual abuse, creating a specific exception to the general comparative negligence rule.

Burden of Proof in an Illinois Comparative Negligence Case

In an Illinois negligence case, the injured person and the defendant have different burdens of proof.

The plaintiff generally must prove by a preponderance of the evidence that the other party was negligent and that the negligence caused the harm suffered.

A plaintiff generally must establish the following elements:

• Duty: The other party owed the plaintiff a legal duty under the circumstances.
• Breach: The defendant failed to meet the applicable standard of care.
• Causation: The defendant’s conduct was a proximate cause of the injury.
• Damages: The plaintiff suffered compensable losses, which may include medical expenses, lost wages, pain and suffering, and other recoverable damages.

When a defendant claims that the injured person also contributed to the accident, Illinois law places a separate burden on the defendant.

Under 735 ILCS 5/2-613, the facts supporting contributory negligence must be plainly stated as part of the defense.

Illinois pattern jury instructions require the defendant to prove both that the plaintiff acted negligently and that the plaintiff’s conduct was a proximate cause of the injury.

The percentage assigned to the plaintiff reflects that conduct as part of the total proximate cause of the harm.

A traffic violation or mistake does not automatically establish comparative fault.

For example, evidence that an injured driver was speeding may be relevant, but the defendant must still connect that speed to how the collision occurred before it can support a reduction in damages.

Police reports, witness statements, photographs, video, vehicle data, and other information may influence how fault is evaluated, while the admissibility and weight of particular evidence can depend on the circumstances of the case.

How Insurance Companies Assign Fault Percentages in Illinois

Insurance companies often assign fault percentages while evaluating an Illinois injury claim, sometimes before all available evidence has been collected.

Adjusters may review statements from the people involved, witness accounts, photographs, video, accident reports, vehicle damage, and other information when deciding how much responsibility to attribute to each party.

That percentage can directly affect a settlement offer. Insurance adjusters leverage fault assignments to reduce settlement offers when they believe the injured person shares responsibility for causing the accident.

For example, an insurer that assigns 25% of the fault to the injured person may offer compensation reflecting only the remaining 75% of the claimed damages.

An insurer’s percentage is not a final legal determination.

The Illinois Department of Insurance explains that the parties may negotiate over comparative negligence and that, when no settlement is reached, the courts make the final determination.

Additional evidence, including witness statements, video, physical evidence, or reconstruction analysis, may also cause an insurer to revise its initial assessment of fault.

Who Determines Fault in an Illinois Comparative Negligence Claim?

Fault may be evaluated by several people during an Illinois injury claim, but those assessments do not all carry the same legal weight.

An insurer may propose a percentage during settlement negotiations, and a police report may contain observations about the accident, but neither automatically determines the final percentage of comparative negligence.

The role of each party differs:

• Insurance adjuster: An adjuster may assign a percentage of fault when evaluating a claim and use that assessment to calculate a settlement offer. The Illinois Department of Insurance explains that an insurer’s assessment can be disputed and negotiated rather than treated as a binding legal finding.
• Responding police officer: A crash report may document statements, citations, diagrams, witnesses, and observations from the scene. That information can affect how insurers and attorneys evaluate the accident, but the report itself does not establish the final percentage of legal fault, and its admissibility in court depends on the circumstances.
• Judge or jury: If the parties cannot resolve the dispute and the case proceeds through litigation, a judge or jury may determine fault based on the admissible evidence and applicable Illinois law. In a jury trial, the jury assigns the percentages of responsibility and determines total damages before the court applies the comparative negligence reduction.

Photographs, surveillance or traffic-camera footage, witness testimony, vehicle damage, electronic data, and accident reconstruction may change an earlier assessment of fault as additional information becomes available.

A percentage proposed by an insurer early in the claim should therefore not be confused with a final legal determination.

Conduct That Does Not Establish Comparative Fault Under Illinois Law

Not every allegation made against an injured person can be used to assign comparative fault.

Illinois law places specific limits on certain conduct, while other issues may affect damages without changing responsibility for causing the original accident.

Not Wearing a Seat Belt

Under 625 ILCS 5/12-603.1, Illinois generally requires drivers and passengers to wear properly fastened seat belts, subject to statutory exceptions.

The same law expressly provides that failure to wear a seat belt is not evidence of negligence, does not limit an insurer’s liability, and cannot be used to reduce damages arising from the operation of a motor vehicle.

An injured person therefore should not receive a comparative-fault percentage simply because they were not wearing a seat belt.

Not Wearing a Motorcycle Helmet

Illinois does not currently impose a general motorcycle helmet requirement, although state law does require motorcycle riders to use specified forms of eye protection under 625 ILCS 5/11-1404.

Illinois appellate courts have also rejected the argument that failure to wear a motorcycle helmet should be treated as comparative negligence or used to reduce damages.

A rider’s failure to wear a helmet therefore does not, by itself, establish fault for causing or worsening a motorcycle accident claim.

Delays in Getting Medical Treatment

A delay in seeking medical treatment is generally different from conduct that contributed to causing the original accident.

It may instead raise a separate question about whether the injured person used reasonable care to limit or mitigate later damages.

Illinois jury instructions recognize that damages caused by a failure to exercise ordinary care in obtaining treatment may be excluded when the resulting harm can be separated from the original injuries.

The effect of delayed treatment therefore depends on the medical circumstances and whether the delay actually caused additional harm, rather than automatically creating comparative fault for the accident itself.

Injured Children and the Illinois Standard of Care

Illinois does not always judge an injured child’s conduct by the same standard that applies to an adult.

The Illinois Pattern Jury Instructions generally consider the child’s age, mental capacity, experience, and the circumstances surrounding the accident when evaluating contributory negligence.

The applicable standards include:

• Children under 7: Illinois treats a child under seven as incapable of contributory negligence, so the child cannot be assigned a percentage of fault.
• Children age 7 and older: A child is generally compared with a reasonably careful child of the same age, mental capacity, and experience rather than with an ordinary adult.
• Minors engaged in adult activities: A minor operating a motor vehicle or participating in certain other activities normally undertaken by adults may be held to the same standard of care as an adult.

A defendant may still argue that an older child’s conduct contributed to an accident, but the child’s actions must be evaluated under the appropriate standard rather than automatically applying the rules used for adults.

Fault can also be shared among multiple parties involved in an accident when the evidence supports assigning responsibility to more than one person.

The percentage attributed to the injured child, if any, can then affect recovery under Illinois comparative negligence law.

Evidence Used to Dispute Fault Under Illinois Comparative Negligence Law

When fault is disputed, the available evidence can help establish how an accident occurred, whether the injured person acted negligently, and whether that conduct contributed to the resulting harm.

The same evidence may support, reduce, or contradict a percentage of comparative fault proposed by an insurance company or another party.

Relevant evidence may include:

• Photographs of the scene: Images can document vehicle positions, road conditions, debris, visibility, property hazards, or other conditions present when the accident occurred.
• Vehicle or property damage: Impact points, damage patterns, or physical defects may help explain how an accident happened.
• Witness statements: Independent witnesses may support or contradict the accounts given by the people involved.
• Video footage: Traffic cameras, security systems, dashcams, or nearby businesses may have recorded the accident or events leading up to it.
• Electronic data: Event data recorders and other available electronic information may provide details about speed, braking, vehicle movement, or other activity.
• Phone records: In appropriate cases, records may help address allegations of distraction.
• Expert analysis: Accident reconstruction or other qualified experts may analyze disputed questions involving speed, movement, visibility, timing, or causation.

Some information can disappear quickly after an accident.

Surveillance footage may be overwritten, vehicles may be repaired or sold, and physical conditions at the scene may change.

When important evidence is controlled by another person or business, an early preservation request may help prevent relevant material from being routinely deleted or destroyed.

Steps to Take When an Insurer Says You Were Partly at Fault

An insurance company’s allegation that you share responsibility does not determine the final outcome of an Illinois injury claim.

When two parties dispute how an accident occurred, photographs, witness accounts, video, physical evidence, and other records may affect the percentage ultimately assigned to each person.

Because your damages may be reduced by your percentage of fault, it is important to understand what supports the insurer’s position and protect information that may contradict it.

Steps to consider when fault is disputed include:

• Preserve available evidence: Keep photographs, videos, dashcam files, damaged property, repair records, and other materials related to the accident in their original form.
• Identify witnesses and video sources: Witness accounts and footage from nearby businesses, homes, traffic cameras, or other sources may help establish what happened before important information disappears.
• Review the accident report: A report may identify witnesses, statements, citations, or factual details that should be compared with photographs, video, and other available information.
• Continue appropriate medical care: Treatment records can document the injuries suffered and whether they are consistent with the accident.
• Be careful with recorded statements: Illinois does not prescribe a specific set of information that must be provided to the other driver’s insurance company, and a third-party claimant does not have the same contractual duties owed to their own insurer. Before providing a recorded statement, understand who is requesting it and how it may be used.
• Preserve insurance communications: Keep letters, emails, settlement offers, and explanations showing how the insurer calculated or justified its proposed percentage of fault.
• Consider legal advice when liability is disputed: A lawyer can review the basis for the insurer’s position, identify additional information that may be available, and explain the filing deadline that applies to the claim.

Illinois generally provides two years to file an action for personal injuries under 735 ILCS 5/13-202, but exceptions can apply.

For example, many claims against an Illinois local public entity or employee are subject to a one-year filing period under 745 ILCS 10/8-101.

An injured person should therefore confirm the applicable deadline rather than assuming every Illinois personal injury claim follows the general two-year period.

TorHoerman Law: Contact an Experienced Illinois Accident Lawyer Today

When an insurance company argues that you were partly responsible for an accident, the percentage of fault assigned can directly affect whether you recover compensation and how much may be available.

TorHoerman Law represents injured people throughout Illinois in personal injury claims involving disputed liability, comparative negligence, and insurance-company fault allegations.

Our law firm can review the circumstances of the accident, the basis for the insurer’s position, and the available evidence before explaining the legal options that may be available under Illinois law.

Eligible cases are handled on a contingency fee basis, so there are no attorney fees unless compensation is recovered.

If you or a loved one were injured in Illinois and another party or insurer is trying to place some of the blame on you, contact TorHoerman Law for a free consultation.

You can also use the chat feature on this page to discuss your situation and learn whether you may have a claim.