31 Oct, 2023

How Does Illinois Determine Fault in Car Accidents?

Author Todd A. Strong
People talking with the police in road accident area. determine fault in car accident
People talking with the police in road accident area. determine fault in car accident

In Illinois, the rules of negligence help determine fault in car accidents. These rules revolve around the duty of care, breach of duty, cause in fact, proximate cause, and damages. Factors such as the nature of the incident, actions of the party involved, and applicable laws and regulations are considered when determining fault in a car accident.

Illinois uses a modified comparative negligence rule when handling personal injury cases. Under this system, injured parties can only receive compensation if they are below 50% liable for the injuries. What’s more, the recoverable compensation gets slashed by the degree that the injured party was at fault.

The Elements of Negligence

Personal injury cases, where plaintiffs claim damages caused by someone else's failure to act reasonably, stem from negligence. You must prove the defendant owed you a duty of care and did not fulfill it, you were injured, and the defendant's negligence caused your injury to recover compensation in a person injury claim. Discussed below are these elements of negligence in detail:

Duty of Care

A duty of care arises when the applicable law acknowledges a relationship between the plaintiff and the defendant that requires the defendant to behave in a certain way. In a car accident case, every driver must obey traffic laws and keep other road users safe. You must prove that the other driver owed you this duty of care before the accident.

Breach of Duty of Care

On top of proving a duty of care, you must show that the other party breached that duty. The defendant may be considered to have breached such a duty if he or she failed to exercise reasonable care. In car accident cases, this breach of duty of care can take the form of negligent driving behaviors, such as reckless, distracted, or intoxicated driving.

Insurers also have their responsibilities and duties. The law requires them to fairly and promptly investigate accident claims and adhere to the insurance policy's contractual obligations. If they unjustly deny your claim or fail to investigate the claim, that's a breach of duty. You may bring an insurance bad faith claim against such an insurance company.

Cause in Fact of the Injury

The injured party must prove that the defendant's action caused his or her injury. In personal injury cases, the cause in fact of the injury suggests that the plaintiff would not have suffered an injury if the defendant did not act negligently. You must provide evidence, such as police reports that give the police's assessment of the accident, footage of the accident scene, and medical records, to support your claim.

Proximate Cause of Harm

Also known as legal cause, the proximate cause of harm is an underlying cause of an accident. As such, the action of the entity or person who owes you a duty of care should be adequately related to your injuries. If someone else's actions are not a direct influence on the accident and your injury, they do not qualify as a proximate cause.

In the case of a car accident where a car hits a pedestrian who is jaywalking, the driver may be held liable if he or she ignored traffic laws. The injured party's medical expenses, lost wages, and other losses are a direct, foreseeable result of the negligent driver's actions. The injured party can claim these expenses through a car accident claim or lawsuit.


As the injured party, you must prove that someone else's failure to act reasonably resulted in actual damages. Actual damages help reimburse you for expenses directly linked to the accident. They include medical bills, lost wages, property damage, and non-economic damages like pain and suffering.

The Comparative Fault System in Illinois

Comparative negligence laws help determine how the parties directly involved in an accident will share responsibility for damages. A case that follows the comparative fault system will often have an insured party as the first party and the claimant as the third party.

If both parties are at fault for the accident, the comparative negligence rule will help determine who will claim compensation for the losses. It also dictates how much will be pursued as compensation. Illinois is among the few states with modified comparative negligence rules.

Under the Illinois modified comparative negligence rule, you can only claim damages if your fault is 50% or less. You will not receive compensation if the court finds you 51% or more at fault.

How Comparative Fault Impacts a Settlement

The at-fault party's insurer is responsible for settling the claim brought by the injured party. The insurer will consider the degree of the insured driver's negligence to propose a settlement offer. The company will interview those involved in the accident (witnesses included) and review the accident report to determine fault.

If the insurance company finds that you were more than 50% at fault for the incident, it will not offer to settle your damages. In this scenario, you can start a car accident lawsuit in the appropriate court.

The company would deduct your share of liability from the final compensation if it finds that you were less than 50% liable for the accident. However, the value of your settlement will be reduced by the percent of fault you hold.

Factors Considered in Fault Determination

Determining legal responsibility in any personal injury case is based on whether someone else acted carelessly. The following are factors considered when determining who is at fault in an Illinois car accident:

The Nature of the Incident

Understanding the nature of the incident helps you know what caused the accident and resulting injuries. This might involve reviewing physical evidence from the accident scene, witness statements, and the police report. These pieces of evidence help determine if the accident arose from poor road conditions, drunken driving, driver distractions, speeding, or red light jumping.

The Actions of the Parties Involved

The actions of the involved parties, and how those actions contributed to the crash, can help determine fault after a car accident. If one party acted negligently or recklessly, or broke traffic laws, and subsequently caused the crash, he or she may carry sole liability for resulting damages. If both parties acted negligently, they may share fault to some degree.

The Applicable Laws and Regulations

Personal injury cases involving car accidents are usually resolved based on laws and regulations. In particular, car accident victims can claim compensation for their losses or injuries under the Illinois comparative fault system. Illinois law also requires motorists to report car accidents resulting in property damage worth $1,500 or more or bodily injury.

Your case must meet the rules of negligence defined under Illinois law to claim compensation. If your case meets these rules, the court will determine the percentage of negligent actions and fault of each party involved in the crash. It will refer to the relevant regulations and look for negligent actions, such as reckless driving, intoxication, disregard of traffic signals, distraction, and speeding.

The Standards of Care That Were Expected

If an individual breaches the duty of care and his or her actions harm someone else, that individual will be liable for the resulting injuries. A court will consider the standards of care expected by the parties involved in an accident. The standard of care is the level of care a reasonable individual would exercise in a similar situation.

How to Prove Fault in an Accident Case

Proving fault in an accident case helps determine whether you will get compensated for your injuries or losses. It can also help estimate the compensation you can claim under Illinois law.

To prove fault in your accident case, you must show that someone else was negligent.

Negligence means that that person or entity failed to act reasonably. You can prove negligence by gathering the following pieces of evidence:

  • Police report, containing details about the accident, names and contact information of the motorists, and the officer’s assessment of the party at fault.
  • Photographs and videos of the accident scene showing your injuries and damage to the vehicles.
  • Witness statements
  • Medical records documenting the injuries sustained and the type of treatment you sought

The sooner you collect evidence, the higher the likelihood of building a strong accident case. Evidence can get destroyed or lost, making it challenging to prove that you suffered losses from an accident. As such, consult an experienced car accident attorney to discuss your case and determine which evidence can help prove fault.

About The Author

Photo of Todd A. Strong
Illinois workers’ compensation and personal injury lawyer Todd A. Strong is the founder of Strong Law Offices in Peoria, Illinois. Todd brings considerable legal knowledge, experience, and skill to the table to ensure injured victims throughout the state are treated with respect, dignity, and fairness.