I've contested several traffic tickets, and have won completely every time I've bothered to contest it in court. However, I've just been lucky. One time, the cop had to leave court early so I won by default. Another time I got dinged for not having a valid licence renewal sticker on my plate or my registration, and didn't have my insurance chit with me. Bam! Three tickets. I got the renewal stickers right away and got my insurance document and showed everything to the prosecutor on my court date and they just cancelled all those charges.
In all those situations I was guilty. So, I lucked out for the first ticket, and I guess they considered the other situations pretty minor so they just figured it wasn't worth dealing with in court. Actually I'm surprised they cancelled the ticket for not having my renewal sticker, because I essentially was driving without valid plates for a month or so, but maybe they took it easy on me because it was a first time offence in that regard, and it wasn't for that long. As for the insurance documentation, I already had insurance, but I just didn't have the latest paperwork in the car. In that situation, they routinely cancel the charge once the proper documentation is presented.
I now have another speeding ticket in the courts (going 70 kph in a 50 zone, caught me right where it transitioned from 60 to 50 with a strategically placed radar) so I'm contesting that too. I'll probably lose, but I'm giving it a shot.
I contest some of these tickets not because of the cost of the tickets, but because they can potentially affect insurance rates, as they are moving violations. It actually costs me much more to contest these than paying the fine though, because I use a paralegal to attend court, etc. ie. I'm paying like $500 to contest a $150 ticket.
BTW, for the licence and registration and insurance tickets, funnily enough the cop actually told me how to fight the tickets. He handed me the tickets and then spent a couple of minutes telling me about the process and that I could probably get them cancelled if I showed up in court with the appropriate documents. Nice guy.
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One more thing. In my neighbourhood you are not allowed to have a second kitchen in your house, unless it's a multi-family dwelling. And if it's a multi-family dwelling then it has to meet stricter fire codes, etc. and it can potentially increase your property taxes.
I wanted a second kitchen, not to rent out to a tenant, but just for use for parties, etc. So, obviously, I didn't want to make it into a multi-family dwelling just for this for lots of extra cost. I went to city bylaw/zoning committee and asked for a zoning variance just for my house. After going through all the necessary hoops, I plead my case in front of the committee they approved it. So my house is the only one in the neighbourhood AFAIK that allows this without being a multi-family dwelling. It was a 2-1 vote by the committee to allow it for me.
So yeah, here again I fought the law but we both won. Effectively I am within the law, because a variance in the law was allowed just for my house.