How fault is decided after an accident
In plain English: fault is legal responsibility for causing an accident. The person or business at fault, or in practice their insurer, usually has to pay for the harm. Fault can be shared, and the split often matters as much as who was mainly to blame.
Who actually decides
People often assume the police decide fault. They don't, at least not for a civil claim. A police report is strong evidence, and a traffic ticket can help, but insurers and courts make their own decisions. In practice:
- Insurance adjusters make the first call, based on statements, photos, damage patterns and the police report.
- Negotiation between insurers, or between your lawyer and the insurer, settles most disputes.
- A judge or jury decides only if the claim goes to trial.
In Ontario, insurers apply the province's Fault Determination Rules, a regulation with set diagrams for common crash types, to decide fault for insurance purposes. That can be different from fault in a lawsuit.
Fault when blame is shared
Many accidents are partly both drivers' fault. What happens next depends on where you are:
- Most US states reduce your award by your percentage of fault, either without limit or with a cut-off, usually around 50%.
- Alabama, Maryland, North Carolina, Virginia and Washington DC can bar your claim if you're at fault at all.
- The UK and Canada reduce your damages by your share of responsibility.
Fault and no-fault systems
In no-fault US states and some Canadian provinces, your own insurer pays certain benefits, such as medical costs and some lost income, regardless of fault. Fault still matters for suing the other driver for pain and suffering, which is often allowed only above an injury threshold, and it can affect your premiums.
You're rear-ended at a junction. The other driver says you braked suddenly for no reason. Dashcam footage showing a pedestrian stepping out in front of you turns a disputed claim into a straightforward one.
Evidence that settles fault arguments
- Photos of the scene, vehicle positions and damage.
- Dashcam, doorbell or shop CCTV, which is often deleted within days.
- Names and numbers of independent witnesses.
- The police report or incident number.
- Vehicle data in more serious crashes.
Adjusters sometimes suggest a 50/50 split early because it's quick. Once you agree, it's hard to reverse. Ask what evidence supports their view and take time before responding.
Next: fault vs no-fault insurance · police report · car accident claims.
Related terms
General information, not legal or medical advice. Rules differ between US states, the UK and Canadian provinces, so check the law where your accident happened. How we write and check · Legal disclaimer