Illinois’ Modified Comparative Negligence Laws and Vehicle Claims


Illinois follows a modified comparative negligence system when determining liability and compensation in vehicle accident claims involving negligent parties. Under this system, a plaintiff’s own negligence does not automatically bar recovery of damages, but it may reduce the amount of damages the plaintiff can recover in a Chicago personal injury case.

Comparative Negligence Overview

Comparative negligence laws determine how responsibility for damages is allocated between multiple negligent parties in an accident. It involves comparing the fault of each party and assigning percentages of responsibility based on their relative degrees of negligence.

Traditional contributory negligence rules completely barred a plaintiff from recovering any damages if they were even slightly at fault for causing the accident. Comparative negligence modifies this harsh doctrine to allow plaintiffs to recover damages reduced by their percentage of fault, as long as their negligence is not greater than the defendant’s.

There are two comparative negligence systems:

  • Pure comparative negligence: Plaintiffs can recover reduced damages even if they are more than 50% at fault. Damages are reduced by the plaintiff’s percentage of fault.
  • Modified comparative negligence: Plaintiffs whose negligence exceeds a specified threshold cannot recover anything. Most states set this bar at 50% – plaintiffs more than 50% at fault cannot recover. A minority use a 51% threshold, barring recovery only if the plaintiff’s negligence is greater than the combined fault of all other parties.

Illinois applies modified comparative negligence with a 50% rule. Plaintiffs more than 50% at fault are completely barred from recovery. If the plaintiff’s fault is 50% or less, their damages are reduced by their percentage of negligence.

Determining Fault in Vehicle Accident Claims

To determine comparative fault, courts examine the negligent actions of each party that contributed to the accident and injuries. Key factors include:

  • Traffic law violations – e.g., speeding, illegal turns, running stop signs
  • Inattentive, careless, or reckless driving
  • Failure to use headlights, signals, or brake lights properly
  • Distracted driving due to cell phone use, eating, passengers, etc.
  • Intoxication from alcohol or drugs
  • Faulty vehicle maintenance and equipment malfunctions
  • Ignoring hazardous weather and road conditions

In auto accident lawsuits, both the plaintiff(s) and defendant(s) often make allegations of comparative negligence against each other. The court or jury must then decide the relative fault percentages to assign to each party based on the evidence.

Sometimes the negligence of a non-party, such as a manufacturer, mechanic, or government entity responsible for road design and maintenance, may also contribute to an accident. Illinois allows defendants to assert a “non-party defense” to have the non-party’s negligence considered in allocation of fault, even if they are not actually a defendant in the lawsuit.

Effects of Comparative Negligence on Damages

If the plaintiff is partially at fault for the accident, their recovered damages are reduced proportionately by their percentage of fault.

For example, if the plaintiff’s damages are assessed at $100,000 and they are found 25% responsible, their recoverable damages are lowered to $75,000 (100% – 25% = 75% of $100,000).

Damage categories that may be reduced due to the plaintiff’s comparative negligence include:

  • Medical expenses cover the present and future costs of reasonable and necessary medical treatment, rehabilitation services, medications, assistive devices, and in-home care required due to accident injuries. Economic analyses are used to project life expectancy and future medical needs.
  • Lost income and reduced earning capacity accounting for both past and future wage losses and diminished ability to earn income over one’s career due to disability or disfigurement. Work-life expectancy, promotions, and fringe benefits are considered in calculating losses.
  • Property loss/damage to vehicles involves the repair or replacement cost for the plaintiff’s damaged vehicle. Evaluating property damage to other personal property requires considering original value, age, used value, and replacement costs.
  • Pain and suffering compensation covers physical discomfort and distress resulting from injuries like broken bones, burns, trauma, or loss of limb. The severity and duration are important when placing a monetary value on the pain.
  • Disability and disfigurement damages account for permanent limitation, loss of mobility, disability ratings, and impact on quality of life, as well as cosmetic scarring from burns, lacerations, or amputations that affect personal body image and self-esteem.
  • Mental anguish includes fright, nervousness, grief, anxiety, worry, and PTSD-type symptoms like insomnia, nightmares, and flashbacks arising from a traumatic accident and injuries.
  • Loss of consortium addresses loss of affection, companionship, intimacy, moral support, guidance, services, and assistance when an injured spouse suffers reduced ability to fulfill their marital duties and roles.

Punitive damages are not reduced by comparative negligence in Illinois. Courts reason that reducing punitive damages would improperly allow a plaintiff’s negligence to frustrate the policy goals of punishment and deterrence that punitive damages are designed to promote.

Defenses in Vehicle Injury Claims

In addition to asserting comparative negligence, defendants also frequently raise other defenses in efforts to defeat or limit their liability, including:

  • Failure to mitigate damages – Plaintiffs must take reasonable steps to minimize the extent of their injuries and losses after an accident. Failure to follow medical advice, seek prompt treatment, or avoid aggravating activities may reduce recoverable damages.
  • Failure to preserve evidence – Plaintiffs must preserve important evidence such as photos of vehicle damage, accident site conditions, and medical records. Discarding or altering evidence may result in spoliation sanctions negatively impacting the plaintiff’s case.
  • Statute of limitations – Lawsuits must be filed within the statutory time limits, which are two years for personal injury and five years for property damage in Illinois. Exceeding the statute of limitations will completely bar recovery.

Illinois applies a modified comparative fault system that allows vehicle accident plaintiffs to recover damages reduced by their percentage of negligence unless they are more than 50% at fault. Defendants frequently assert comparative negligence and other defenses to limit their liability exposure in such cases. The factfinder must determine relative fault based on the contributing negligent actions of each party.

If you need advice on a car accident lawsuit where both parties are liable, speak to one of your experienced attorneys. We have offices in 32 locations and 19 states, including Chicago.

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