Fault determination is regulated. Auto Insurance Tips.

With auto accidents, someone is always determined to be “at-fault”, either partially or fully. Here’s why:
Insurance companies—guided by provincial law called theInsurance Act and its Fault Determination Rules—must assess the degree of fault to be assigned to each driver, to determine the type of property damage coverage that applies to the accident.Fault is also used by insurance companies to determine future rates for the at-fault driver(s).
To get a better understanding of fault assessment, take a look at the most frequently asked questions on the subject, answered by the Financial Services Commission of Ontario (FSCO), the regulator of the auto insurance industry in Ontario:

Q: Can fault in an auto accident be shared?
A: Yes. The circumstances may show that more than one driver was partially at-fault for insurance purposes.
Q: How does an at-fault accident affect me?
A: It’s a matter of degree. A driver can be anywhere from 100 percent to zero percent at-fault, but if it’s anything more than zero percent, it will put an “at-fault accident” on your insurance record, and your rates will likely go up.
Important: Did you know that when you lend your vehicle to someone, you are also lending your insurance? If that person has an at-fault accident, it will go on your insurance record, and it will be your insurance rates that will go up.
Q: How do police charges or convictions affect an insurance company’s decisions?
A: Police charges are a significant factor, but if you are charged with an offence, you will not necessarily be found at-fault for insurance purposes. Similarly, if the police don’t file charges, it does not necessarily mean that the insurance company review won’t find one or more of the drivers at-fault. Drivers are individually assessed under the Fault Determination Rules.

Q: What should I do if I disagree with the decision of my insurer?
A: Speak to the claims adjuster handling your file and ask which Fault Determination Rule has been applied to your case. Generally, an insurance company will only revise or reconsider its decision on fault if new and relevant information is provided. If you still disagree with your insurance company, contact the company’s complaint officer, who will guide you through the complaint-handling procedures.

More information on auto insurance and the Fault Determination Rulesis available online at www.fsco.gov.on.ca where you can download the brochure After an Auto Accident: Understanding the Claims Process.
-- News Canada