Comparative Negligence Rules in Illinois

In Illinois, being partly at fault doesn't end your car accident claim, but crossing 51% does. Here is how the state's modified comparative negligence rule works, straight from the statute.

ThatCarHitMe.com Editorial
Jul 26, 2026
6 min read

If you were partly to blame for your crash in Illinois, you can still recover money in most cases. The state dropped the old all-or-nothing approach decades ago, so a single mistake by the injured driver no longer wipes out the claim. Illinois runs on modified comparative negligence, and the number that decides everything is 50%.1

The scale of the problem is easy to underestimate. Chicago alone logged 109,112 reported crashes in 2025,2 and the city recorded another 9,461 in January 2026.3 In a large share of those wrecks, both drivers did something wrong, and how Illinois divides the blame is what decides who pays.

The 51% rule

The controlling law is Section 2-1116 of the Illinois Code of Civil Procedure, 735 ILCS 5/2-1116. It says a plaintiff "shall be barred from recovering damages if the trier of fact finds that the contributory fault on the part of the plaintiff is more than 50% of the proximate cause of the injury or damage for which recovery is sought."1 Stay at or below 50% and you can still recover, but "any damages allowed shall be diminished in the proportion to the amount of fault attributable to the plaintiff."1 The Illinois Department of Insurance describes the same standard for drivers: you recover only if you are not more than half at fault, and your payout is reduced by your share.4

That wording matters. Illinois draws the line at "more than 50%," so a driver found exactly 50% at fault still recovers half of their damages. A state that uses a flat 50% bar would hand that same driver nothing. Illinois sits on the more forgiving side of that split.1

The math is where this gets real. Say your losses come to $100,000. If a jury puts you at 30% at fault, you collect $70,000. At an even 50%, you still collect $50,000. Cross to 51% and you get nothing. That single percentage point is the gap between half a recovery and zero, which is why people call it the "51% bar."

How Illinois landed on that line

For most of the last century, Illinois was a contributory negligence state, one of the harshest rules on the books. If you were even 1% at fault, you lost the whole case. The Illinois Supreme Court scrapped that in 1981 in Alvis v. Ribar, 85 Ill. 2d 1, and replaced it with pure comparative negligence, under which a plaintiff who was 90% at fault could still recover the remaining 10%.5 Five years later the General Assembly pulled it partway back. Public Act 84-1431, effective for causes of action accruing on or after November 25, 1986, wrote the modified 51% bar into 735 ILCS 5/2-1116.1 The cutoff was a legislative decision, and it is why Illinois now sits between the pure-comparative states and the handful that still bar any at-fault plaintiff.

Who decides your percentage

Under the statute, the percentage is set by the trier of fact, which means the jury, or the judge in a bench trial.1 Most claims never get that far. They settle, and during settlement the insurance adjusters assign their own fault figures, which is where the real fight usually happens. Illinois is an at-fault state, not a no-fault state,4 so there is no injury threshold you have to clear before going after the other driver. You build the liability case from day one, and the police report and independent witnesses often carry it. If you need the official record, start with your Illinois crash report.

The seat belt exception most drivers miss

Here is a rule that catches people off guard. Illinois requires seat belts, yet not wearing one cannot be used to shrink your recovery. Under 625 ILCS 5/12-603.1, failure to wear a seat safety belt "shall not be considered evidence of negligence, shall not limit the liability of an insurer, and shall not diminish any recovery for damages."6 A defense lawyer cannot point to an unbuckled belt to argue your injuries were partly your own fault and push your percentage higher. Plenty of other states allow exactly that argument. Illinois does not.

Your percentage also controls what you can collect

Fault does more than scale your award. It also decides which defendant you can chase for the full amount. Under 735 ILCS 5/2-1117, a defendant found less than 25% at fault is only severally liable for your non-medical damages, so that party pays just its own slice of things like pain and suffering.7 A defendant at 25% or more is jointly and severally liable, which means you can collect the entire non-medical award from it even if another at-fault driver is broke or uninsured.7 And every liable defendant, whatever its percentage, stays jointly and severally liable for your past and future medical expenses.7 In a multi-car pileup with an underinsured driver, those thresholds can matter as much as the raw split of blame.

The two-year clock still applies

Being partly at fault does not change your filing deadline, but the deadline can end a claim no matter who was to blame. Most Illinois injury lawsuits have to be filed within two years of the crash under 735 ILCS 5/13-202.8 Property damage runs on a longer clock, five years under 735 ILCS 5/13-205.9 If your repaired vehicle is worth less on paper than it was before the wreck, that longer window is what covers a diminished value claim. Sorting out a contested fault percentage takes time, so if your share is in dispute it is worth finding an attorney early.

Why the percentage is worth fighting over

Fault in a real crash is rarely a clean 100 to 0. The other side's insurer has a direct incentive to nudge your number toward 51, because at 51 it owes you nothing. Getting your own read on liability, backed by the report and the physical evidence, is how you keep your percentage in the range where the statute still lets you recover.

This article is general information, not legal advice.

Sources

  1. Illinois General Assembly, 735 ILCS 5/2-1116, Code of Civil Procedure (limitation on recovery in tort actions). https://www.ilga.gov/legislation/ilcs/fulltext?DocName=073500050K2-1116

  2. thatcarhitme.com, Chicago Year-over-Year Crash Report, 2025. https://thatcarhitme.com/crash-data/illinois/chicago/2025-annual-report

  3. thatcarhitme.com, Chicago Crash Report, January 2026. https://thatcarhitme.com/crash-data/illinois/chicago/january-2026-report

  4. Illinois Department of Insurance, Comparative Negligence. https://idoi.illinois.gov/consumers/consumerinsurance/comparative-negligence.html

  5. Alvis v. Ribar, 85 Ill. 2d 1 (Ill. 1981). https://law.justia.com/cases/illinois/supreme-court/1981/52875-5.html

  6. Illinois General Assembly, 625 ILCS 5/12-603.1. https://www.ilga.gov/legislation/ilcs/fulltext?DocName=062500050K12-603.1

  7. Illinois General Assembly, 735 ILCS 5/2-1117. https://www.ilga.gov/legislation/ilcs/fulltext?DocName=073500050K2-1117

  8. Illinois General Assembly, 735 ILCS 5/13-202. https://www.ilga.gov/legislation/ilcs/fulltext?DocName=073500050K13-202

  9. Illinois General Assembly, 735 ILCS 5/13-205. https://www.ilga.gov/legislation/ilcs/fulltext?DocName=073500050K13-205

About This Guide

Written by: ThatCarHitMe.com Editorial

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