Illinois Comparative Negligence — How Shared Fault Affects Your Injury Claim

Under 735 ILCS 5/2-1116, contributory fault does not bar recovery as long as the plaintiff's fault is not more than 50% of the proximate cause of the injury or damage. In practical terms: if your fault is 50% or less, you can recover damages. If your fault exceeds 50% — meaning 51% or more — you recover nothing.

The statute uses precise language: recovery is barred when the plaintiff's fault is "more than 50%." At exactly 50% fault, you are not "more than" 50%, so recovery is still permitted. Your award is reduced by your fault percentage. On $200,000 in damages with 50% fault, you take home $100,000. At 51% fault, that drops to zero. That single percentage point can mean the difference between a six-figure recovery and nothing.

Illinois's threshold is a hard rule. There is no judicial discretion to award partial damages to a plaintiff who is more than 50% at fault, regardless of the severity of their injuries. This makes the fault determination — and the evidence supporting it — the most important battleground in most Illinois personal injury cases.

Illinois has not always used this system. Originally, the state followed pure contributory negligence — if you were even 1% at fault, you recovered nothing. In 1981, the Illinois Supreme Court adopted pure comparative negligence in Alvis v. Ribar, allowing recovery regardless of the plaintiff's fault percentage (reduced proportionally).

The Illinois legislature overrode that ruling in 1986 with P.A. 84-1431, establishing the modified comparative negligence system with a "not greater than 50%" bar. The current version of the statute, 735 ILCS 5/2-1116, derives from P.A. 89-7, effective March 9, 1995. The system has been stable since then — Illinois has used modified comparative negligence for nearly 40 years.

Understanding this history matters because you may encounter outdated information online suggesting Illinois uses pure comparative negligence. It does not. Illinois has a firm 50% threshold, and it has been in place since 1986.

The math is straightforward once fault percentages are assigned. If your total damages are $100,000 and you are 0% at fault, you recover the full amount. At 20% fault, you recover $80,000. At 30% fault, $70,000. At 50% fault — the maximum allowed — $50,000. At 51% fault, nothing.

Consider a rear-end collision on I-290 near the Chicago suburbs. You were changing lanes when the driver behind you, who was following too closely and looking at their phone, struck you. A jury might assign you 15% fault (for the lane change without adequate signaling) and the other driver 85% fault (for tailgating and distracted driving). On $150,000 in damages, you recover $127,500 — your $150,000 reduced by 15%.

Now consider a more contested scenario. You entered an intersection as the light turned yellow. The other driver ran the red while speeding. A jury assigns you 40% fault (for entering on yellow when you could have stopped) and the other driver 60% fault (for running the red while speeding). On $100,000 in damages, you recover $60,000. If the jury had assigned you 51% instead, you would recover nothing — which is why the evidence you present about the other driver's behavior is critical.

When multiple defendants are involved, the trier of fact determines each party's percentage of fault — including the plaintiff's. Under 735 ILCS 5/2-1117, a defendant whose fault is less than 25% is generally liable only for their proportionate share of the damages. Defendants at 25% or more fault may face joint and several liability for certain types of damages.

Example: You are 30% at fault. Defendant A is 50% at fault. Defendant B is 20% at fault. Your total damages are $200,000. Your recoverable amount is $200,000 reduced by 30% = $140,000. Defendant A, at 50% fault (25% or more), may be jointly and severally liable. Defendant B, at 20% fault (under 25%), pays only their proportionate share of $40,000.

The allocation of fault among multiple defendants can significantly affect your recovery, especially when one defendant has limited insurance or assets. An experienced attorney can evaluate which defendants to pursue and how fault allocation is likely to play out based on the evidence.

The trier of fact — a jury in most cases, or a judge in a bench trial — determines each party's percentage of fault based on the evidence. During the insurance claims process, adjusters make initial assessments that drive settlement offers. If the case goes to trial, the jury has the final word.

Key evidence includes police reports, witness statements, photographs, dashcam and surveillance video, vehicle damage analysis, electronic data recorder (EDR) data, and expert accident reconstruction. Police reports are important during negotiations but may not be admissible at trial for the truth of the officer's fault conclusions — they can be used to refresh witness memory and document scene conditions.

The statute defines fault broadly. Under 735 ILCS 5/2-1116, "fault" includes negligence, willful and wanton conduct, and any other basis of liability in tort. This means the comparative negligence analysis applies whether the defendant was merely careless or acted with reckless disregard for safety.

Insurance adjusters in Illinois are trained to maximize the fault percentage assigned to you. Every percentage point they add to your fault directly reduces what they pay — and pushing you past 50% eliminates the claim entirely. On a $200,000 claim, shifting your fault from 20% to 40% saves the insurer $40,000. Shifting it to 51% saves $200,000.

Common adjuster arguments include: you were speeding (even 5 mph over the limit), you were not wearing a seatbelt, you were distracted by your phone, you did not seek medical treatment quickly enough (implying your injuries are not serious), or you made a statement at the scene that could be interpreted as admitting fault. Adjusters will review police reports, medical records, and social media for anything that supports a higher fault assignment.

Protect yourself by documenting everything immediately after the accident. Photograph the scene and all vehicles from multiple angles. Get names and phone numbers of independent witnesses. Request the police report. Save any dashcam footage. Seek medical attention the same day — even if you feel okay, because soft tissue injuries and concussions often do not produce symptoms for 24-72 hours. Do not give a recorded statement to the other driver's insurance company without legal counsel.

The strongest fault evidence is objective and created at or near the time of the accident. Scene photographs taken within minutes of the collision, dashcam footage, traffic camera video, and 911 call recordings are difficult for the other side to dispute. Electronic data recorder (EDR) data from modern vehicles provides pre-impact speed, braking force, and steering inputs — hard data that can establish what each driver was doing before the collision.

Medical records play a dual role. Prompt treatment documents the link between the accident and your injuries, while gaps in treatment give the insurer room to argue that your injuries are pre-existing or not accident-related. Follow your doctor's treatment plan completely, attend every appointment, and keep records of every visit, prescription, and therapy session.

In serious or high-dispute cases, expert accident reconstruction can shift fault significantly. A reconstructionist analyzes physical evidence — vehicle damage, road marks, debris patterns, sight lines — to build a physics-based model of what happened. In a system where the difference between 50% and 51% fault determines whether you recover anything at all, even a small shift in the numbers can determine the outcome of your case.

Wondering how fault might affect your case? Get your free Injury Claim Check. You will answer a few questions about your accident and injuries, and we will provide a personalized report that includes how Illinois's comparative negligence rule applies to your situation, what your claim may be worth after any fault reduction, and whether connecting with an Illinois personal injury attorney makes sense for your case.

Insurance companies are already building their case to assign you fault. The sooner you understand where you stand, the better positioned you are to protect your claim. Free, confidential, and takes less time than waiting on hold with an insurance company.