Some insurance companies treat +30km/h as major offences, but most treat up to +49 as minor. You have to look at your insurance policy, you'll have "conviction free discounts" that will get removed; on top of that, they'll add surcharges per conviction.
I believe with SF on the first minor conviction you're already at +20%, because you lose +10% discount for no longer being conviction free, and +10% per conviction:
http://s982.photobucket.com/user/vifferfun/media/MajorRatingVariables.jpg.html
State Farm will cancel your policy on the third minor conviction; most may cancel your policy if you have a major/serious conviction:
http://assets.ibc.ca/Documents/Brochures/Ontario-Auto-Insurance-FAQ-ON.pdf (Page 11 & 12)
If you have had a clean driving record for the better part of a decade, they won't spend money running your abstract on every renewal. They've been wasting money on that with no return, so they'll stop doing it after a while and focus it more on the 16yr old M1 with a Busa.
If you're getting a new policy from a new insurance provider, they'll see it and will consider it.
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In general, it's not going to be the difference between taking transit and riding/driving; but it will make you think twice about the real consequences of traffic convictions; the buck doesn't stop with the $45 conviction.
Just imagine if you're already paying $2000/yr for SF; on a first minor conviction of +15km/h you'll be paying at least +$1200 in additional premiums for the next three years. How insane is that? Imagine if the prosecutor told you this when you plea-bargained?
Investing in a $300 paralegal to fight that ticket, doesn't seem so bad anymore.
Insurance companies give zero ****s about demerit points; they'll only be interested if as a result of accumulating demerit points (ie. 15pts) you're license was suspended, during which time... you're no longer insurable.