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How Comparative Fault Works in Illinois Personal Injury Cases

You were rear-ended at a stop light, but the insurance adjuster says you share some fault because your brake lights were out. Or you slipped on ice in a store parking lot, but the defense argues you should have seen the ice and walked around it. In Illinois, the fact that you may bear some responsibility for your own injuries does not automatically bar you from recovering compensation. But it does affect how much you can recover, and in some cases, it can eliminate your claim entirely.

Illinois’s Modified Comparative Fault Rule

Illinois follows a modified comparative fault system, codified at 735 ILCS 5/2-1116. Under this rule, your damages are reduced by your percentage of fault. If a jury finds that your total damages are $200,000 and you were 20 percent at fault, your recovery is reduced to $160,000. The critical threshold is 50 percent: if you are found to be 50 percent or more at fault, you recover nothing.

This is different from a pure comparative fault system, where a plaintiff can recover something even if they are 99 percent at fault. It is also different from the old contributory negligence rule, which some states still follow, where any fault on the plaintiff’s part bars recovery entirely. Illinois’s approach is a middle ground, but the 50 percent bar makes fault allocation one of the most consequential issues in any personal injury trial.

How Fault Is Allocated

In a case that goes to trial, the jury decides each party’s percentage of fault based on the evidence. Illinois Pattern Jury Instruction B45.01 instructs the jury to compare the plaintiff’s fault with the fault of each defendant and to reduce the plaintiff’s damages accordingly. The jury considers the conduct of all parties: the plaintiff, the defendant or defendants, and any third parties whose fault contributed to the injury.

In practice, fault allocation begins well before trial. The insurance adjuster’s initial evaluation of the claim includes an assessment of comparative fault. If the adjuster believes the plaintiff bears 30 percent fault, that assessment influences the settlement offer. Your attorney’s job is to challenge the adjuster’s fault allocation with evidence: the police report, witness statements, physical evidence from the scene, and expert testimony where appropriate. A strong factual presentation can shift the adjuster’s fault assessment and significantly increase the settlement value.

Common Comparative Fault Arguments

Insurance companies raise comparative fault in nearly every personal injury case. In car accident cases, common arguments include speeding, distracted driving, failure to wear a seatbelt, and failure to maintain a safe following distance. In premises liability cases, the defense may argue that the hazard was open and obvious, that the plaintiff was not paying attention, or that the plaintiff was wearing inappropriate footwear. In workplace injury cases brought against third parties, the defense may allege that the plaintiff failed to follow safety procedures.

The seatbelt defense deserves specific mention. Illinois law at 625 ILCS 5/12-603.1 limits the use of seatbelt non-use as evidence. A defendant can argue that the plaintiff’s failure to wear a seatbelt contributed to the severity of injuries, but the maximum reduction for seatbelt non-use is capped at 5 percent of the total fault. This is a statutory exception to the general comparative fault framework. Learn more about how fault affects car accident claims on our car accident practice area page.

Multiple Defendants and Joint Liability

When more than one defendant is at fault, Illinois law determines whether they are jointly and severally liable or only severally liable. Under 735 ILCS 5/2-1117, a defendant who is found to be less than 25 percent at fault is only severally liable, meaning they pay only their own share. A defendant found 25 percent or more at fault can be held jointly and severally liable for all of the plaintiff’s damages, minus the plaintiff’s own fault percentage. This distinction matters in cases involving an insolvent or uninsured defendant: if one defendant cannot pay, the remaining defendants who are 25 percent or more at fault may be required to cover the shortfall.

Protecting Your Claim Against Comparative Fault Arguments

The best defense against a comparative fault argument is evidence. Dashcam footage, security camera footage, witness testimony, and physical evidence from the scene can all help establish what actually happened. In car accident cases, cell phone records can rebut a distracted driving allegation. In slip-and-fall cases, photographs of the hazard and the surrounding area can show that the condition was not as obvious as the defense claims. Testimony from the plaintiff about their own conduct, presented honestly and consistently, is important. Juries can tell when someone is being straightforward, and credibility affects fault allocation.

Injured? Get the Help You Deserve.

The attorneys at Parker & Parker offer free, no-obligation consultations. Call (309) 692-8900 or schedule online to discuss your case today.

Frequently Asked Questions

Can I still recover compensation if I was partially at fault?

Yes, as long as your fault is less than 50 percent. Your damages will be reduced by your percentage of fault. For example, if your damages are $100,000 and you are found 25 percent at fault, you would recover $75,000. If your fault reaches 50 percent or more, you recover nothing under Illinois law.

Who decides the percentage of fault?

If the case goes to trial, the jury makes that determination based on the evidence and the jury instructions. In settlement negotiations, fault allocation is a point of negotiation between your attorney and the insurance adjuster. The adjuster will assert a fault percentage that reduces the claim value, and your attorney will present evidence to challenge or reduce that percentage.

Does comparative fault apply to all types of injury cases?

Comparative fault applies to negligence-based claims, which covers the majority of personal injury cases in Illinois. It does not apply the same way to intentional tort claims or strict liability claims, although the defense may still raise the plaintiff’s conduct in those contexts under different legal theories. Workers’ compensation claims operate under an entirely separate system that does not use comparative fault.

If you have been injured due to someone else’s negligence, the experienced personal injury lawyers in Peoria are ready to fight for the compensation you deserve.

How Comparative Fault Works in Illinois Personal Injury Cases