You Were Partly at Fault. Here's What You Actually Recover.

The arithmetic is simple once it is laid out with numbers, so here it is.

The math, with a real number

The Negligence Act (s. 3) tells the court to share out the damages by degree of fault when the plaintiff was also found to be at fault for the loss.

As an illustrative example only: if a court found the other driver 80% responsible and the injured person 20% responsible, and total damages were assessed at $100,000, the recovery would be $80,000. The figures are invented to show the arithmetic and are not a prediction.

Section 4 adds that if it is not practicable to determine the respective degree of fault, the parties are deemed equally at fault. The sections below concern how a percentage is reached, which is argued on the evidence rather than assumed.

What actually moves the percentage

Insurers apply the Fault Determination Rules (R.R.O. 1990, Reg. 668) to work out the degree of fault of their insured. The Insurance Act uses those rules in specific places: to set recovery under the direct compensation provision for vehicle damage (s. 263), and to allocate indemnification between insurers for certain statutory accident benefits (s. 275). Regulation 668 also says that the rules are applied without reference to circumstances such as weather, road conditions or visibility (s. 3). Where section 263 applies, subsection (4) lets an insured bring an action if not satisfied that the degree of fault under the rules accurately reflects the actual degree of fault, and the issues are then decided under the ordinary rules of law. In short, the insurer's percentage is a product of the rules, not a finding by a court on the whole evidence.

In a court action, the judge looks at the conduct of each party in the circumstances. Examples of what is commonly argued:

Seatbelt use. The Highway Traffic Act requires drivers and passengers to wear a seat belt assembly, subject to certain exceptions such as a medical certificate (s. 106). Whether not wearing a belt reduces a damages award, and by how much, is decided by the court on the facts of the case. The Negligence Act (s. 3) looks to fault that contributed to the damages, so the link between the belt and the particular injuries is typically part of the argument. No fixed percentage range is stated in the statutes, and a lawyer can advise on how the question applies to a specific collision.

Speed. If a driver was over the limit when another driver made an unsafe turn, both facts can be weighed. As an illustration only, a court could assign most of the fault to the turning driver and some to the speeding driver. The split in any real case depends on the evidence.

Prior knowledge of risk. A defendant may argue that a passenger who knew a driver was impaired, or who stayed in the vehicle after erratic driving began, bears some share of fault. Whether that argument succeeds, and to what extent, depends on the evidence and the court's view of it.

Right-of-way and signal disputes. Cases where two drivers each say they had the right of way turn on the evidence. Items such as traffic camera footage, independent witness accounts and reconstruction evidence may be relevant, depending on what exists in the particular case.

The percentage that isn't final until you challenge it

An insurer's fault percentage under Regulation 668 is a starting point reached under the rules and the information available at that time. If there is insufficient information about an incident, Regulation 668 says fault is determined under the ordinary rules of law (s. 5), and where two rules apply and one would make the insured 100% at fault while the other would make the insured not at fault, the insured is deemed 50% at fault (s. 4(2)).

A 50/50 figure produced early, before a full investigation or a full set of witness statements, may therefore reflect the rules and the limited information rather than a court's assessment. Section 263(4) of the Insurance Act, described above, is the statutory route for an insured who is not satisfied. Whether challenging a percentage makes sense in a particular case is something a lawyer can advise on.

Accident benefits and fault

Statutory accident benefits are a separate stream from the lawsuit against another driver. Under the Statutory Accident Benefits Schedule (O. Reg. 34/10), the insurer's liability for medical, rehabilitation and attendant care benefits (s. 14) is tied to an insured person having an impairment caused by an accident, and attendant care applies only if the impairment is not a minor injury. The test in that provision is the accident and the impairment, not a percentage of fault. The Schedule also contains exclusions that apply to some other benefits, such as income replacement, for example for certain drivers and for persons convicted of certain offences (s. 31(1)), so the answer for a given person depends on the facts and the policy.

From July 1, 2026, the Schedule makes Parts II, IV, V and VI, which include the income replacement, non-earner and caregiver benefits, optional for policies entered into or renewed on or after that date (s. 2). That means which benefits a person has can depend on the policy. Fault can matter to the lawsuit against another driver and to how insurers deal with vehicle damage and with each other, but it is not what the medical, rehabilitation and attendant care provision turns on. See our article on Ontario accident benefits for more.

Points to consider if you think you were partly at fault

1. Written and recorded statements about fault. Statements made early can become part of the file, and a lawyer can advise before one is given.
2. The police report and any collision reconstruction. Documents of this kind can shape how fault is assessed, so lawyers typically ask for them early.
3. Independent witnesses. They can become hard to find, and memories of details such as which car had the green light fade over time.
4. The insurer's fault percentage. It can be disputed in some circumstances: where section 263 of the Insurance Act applies, subsection (4) allows an insured who is not satisfied that it reflects actual fault to bring an action.
5. The accident benefits claim. It is handled separately; its rules are set out in the Schedule and are not driven by a fault percentage.