Last Updated: April 22, 2026

Yes — Illinois allows you to recover damages even if you were partially at fault for a car accident, as long as your share of fault is 50% or less. Under Illinois modified comparative fault (735 ILCS 5/2-1116), your recovery is reduced by your percentage of fault. At 51% or more, you are barred from recovery entirely. If you were 20% at fault for a $100,000 case, you recover $80,000.

You can sue. Illinois uses modified comparative fault — your damages are reduced by your share of fault, but you are not barred from recovery unless you are more than 50% responsible. If you were 20% at fault for a $100,000 claim, the recovery is $80,000. Most cases where partial fault is alleged settle within that framework with reduced numbers, not at zero.

This article provides general information about Illinois car accident claims and is not legal advice. Every case is fact-specific. If you have questions about your specific situation, call us at (309) 673-0069 for a free consultation.

How Illinois Modified Comparative Fault Works

Illinois adopted modified comparative fault by statute in 1986, codified at 735 ILCS 5/2-1116. The rule has two operative parts:

The damages reduction. If a plaintiff is partially at fault, the damages awarded are reduced by the percentage of fault attributable to the plaintiff.
The 51% bar. If the plaintiff’s percentage of fault is “more than 50% of the proximate cause” of the injury, the plaintiff recovers nothing.

The math is mechanical. A few examples:

10% plaintiff fault on a $50,000 case. Recovery: $45,000.
30% plaintiff fault on a $200,000 case. Recovery: $140,000.
50% plaintiff fault on a $100,000 case. Recovery: $50,000. Still recoverable — 50% is at the bar but not over it.
51% plaintiff fault on a $1,000,000 case. Recovery: $0. The bar is absolute.

The 50%/51% line is unforgiving. A jury that believes the case has merit but assigns the plaintiff 51% of the fault has eliminated the recovery entirely. This is why the percentage allocation in disputed-liability cases often matters more than the gross damages number.

How Fault Is Determined in an Illinois Car Accident

Fault is determined sequentially. The first determination is the insurance adjuster’s, which is informal and based on the police report, recorded statements, and damage photographs. The second is settlement-negotiation determination, where each side argues the percentage. The third — and only legally binding — determination is the jury’s, which is reached only if the case goes to trial.

Evidence that drives the fault determination:

The police crash report. Pulled from the Peoria Police Department, Peoria County Sheriff, Tazewell County Sheriff, or the Illinois State Police, depending on jurisdiction. The reporting officer’s narrative and any traffic citations issued at the scene carry significant weight.
Witness statements. Independent witnesses — passersby, other drivers — are more credible than parties. A consistent witness account that contradicts the at-fault driver’s version often shifts the percentage allocation meaningfully.
Traffic camera footage. Limited in Peoria County compared to larger metros, but available at some controlled intersections.
Accident reconstruction. In disputed-liability cases — particularly intersection collisions and rear-ends with sudden-stop arguments — a reconstruction expert can establish vehicle speeds, angles of impact, and reaction times.
Citations issued at the scene. A traffic citation issued to the at-fault driver under 625 ILCS 5/11 (the rules-of-the-road title) is admissible in some circumstances and creates a strong presumption of fault.

The jury, if the case is tried, is instructed under IPI 11.01 and IPI B45.03 to determine the total damages and then to apportion fault between the parties. The judge applies the comparative-fault math to the verdict before entering judgment.

Common Partial-Fault Scenarios in Peoria County

Several recurring scenarios in our Central Illinois practice generate comparative-fault allegations:

Rear-end with sudden stop. The defense argues the lead driver braked unexpectedly or unnecessarily, or had non-functional brake lights. Even though Illinois follows the rule that a driver must maintain a safe following distance, a documented “phantom stop” or brake-light failure can shift 10–25% of the fault to the lead driver.
Lane change with speeding. The defense concedes the lane change was negligent but argues the rear vehicle was speeding, which contributed to the impact. Speed-of-impact analysis from accident reconstruction can drive these allocations.
Intersection collision with running yellow or marginal red. Both drivers may have been technically at fault — one for running the light, the other for failing to clear the intersection. Signal-phasing analysis matters.
Distracted driving on both sides. A rear-end or merge collision where both drivers were on their phones, eating, or otherwise distracted. Phone records and infotainment logs become evidence.
Failure to wear a seatbelt. Illinois law at 625 ILCS 5/12-603.1 prohibits the failure-to-wear-a-seatbelt defense from being used to reduce damages in personal injury cases. The defense can be raised on the issue of whether seatbelt use would have reduced the injuries, but it does not increase the plaintiff’s percentage of fault for the accident itself.

How Insurance Companies Use Comparative Fault Against You

Adjusters use comparative fault as a negotiation lever. The pattern across the carriers we deal with in Central Illinois:

The “50/50” tactic. Even when liability appears one-sided on the police report, adjusters routinely open at “50/50” on intersection cases or any case where the at-fault driver disputes some part of the narrative. The strategy is to anchor the negotiation at a percentage that, if accepted, halves the recovery.
Inflating fault on unrepresented claimants. Progressive and State Farm both have documented patterns of pushing comparative fault aggressively against claimants without counsel — often citing factors that would not survive cross-examination at trial.
Combining gap arguments with fault arguments. A treatment gap (see our post on refusing medical treatment after a car accident) plus a 30% comparative fault allocation can compound into a 50%+ reduction off a fair value. The two arguments interact.
The 51% threat. In genuinely close cases, the threat of pushing the jury over 51% — and zeroing the recovery — is what drives carriers’ settlement leverage. The threat works because the bar is real.

The defense to all of these is documentation: independent witnesses, the police report’s narrative, expert reconstruction where the case warrants it, and a clear medical record that ties the injuries to the accident. Counsel that anticipates the comparative-fault argument before the carrier raises it negotiates from a stronger position.

Frequently Asked Questions

What does “modified comparative fault” mean in Illinois?

Modified comparative fault is the rule under 735 ILCS 5/2-1116. Your recovery is reduced by your percentage of fault, but you are completely barred from recovery if you are more than 50% at fault. This is different from “pure comparative fault” (which allows recovery at any percentage of fault, even 99%) and from “contributory negligence” (which bars recovery at any percentage of fault). About a dozen states use the modified system at the 51% threshold; Illinois is one of them.

How is the percentage of fault decided?

In settlement, the percentage is negotiated between the parties based on the police report, witness statements, photographs, and expert opinions. In litigation, the jury decides the percentage as part of the verdict — they determine the total damages, then assign a fault percentage to each party, and the judge applies the math before entering judgment. Most cases settle on a negotiated percentage; only the small share that go to trial get a jury allocation.

What if the police report says I was at fault but I don’t think I was?

The police report’s fault determination is not binding in court. Officers respond to a scene with limited information and often make a best-guess fault call that subsequent investigation contradicts. Witness statements, accident reconstruction, traffic-camera footage, and physical evidence of the impact can all support a different conclusion. If your case is otherwise strong, an unfavorable police report is workable — but it raises the cost of the negotiation. Talk to a lawyer before you accept the report’s framing.

Can I still sue if I was speeding?

Yes. Speeding is a contributing factor to fault, but it does not automatically push you over the 51% bar in most cases. The question is the comparative weight of your speeding versus the other driver’s negligence. A driver going 10 mph over the speed limit who was T-boned by a driver running a red light is rarely found more than 50% at fault for the accident.

How does partial fault affect what my case is worth?

Linearly. A 20% finding of fault reduces a $100,000 case to $80,000. A 40% finding reduces it to $60,000. A 50% finding reduces it to $50,000. At 51%, recovery is zero. For more on what determines a case’s gross value before any comparative-fault reduction, see our post on how much your Illinois car accident case is worth.

Worried About Partial Fault? Let’s Talk.

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Can I Sue If I’m Partially at Fault for a Car Accident in Illinois?