IN Ont, NB, NS, when your GVW is 4500kg and up "9920 lbs" you have to cross the scales and you also have to have a log book have a DOT card and have a daily truck inspection and be a member of a random drug testing consortium. "all the stuff 10,000 up trucks put up with in the states". And if you are independent in Ont. above 4500kg you have to have a CVOR# and that cost 250.00 a year
Now for wonderful Quebec. Starting 2009/09/01 they are changing what they call a heavy vehicle "commercial vehicle"
You are considered a Heavy Vehicle in Quebec if you net weight is 3300kg "6600 lbs" or more even if your gvw is under 4500kg
So everyone that goes in to Quebec make sure you check your vehicle registration. That is what they are going to use as your net "empty" weight.
of course vehicles over 4500kg are still called Heavy Vehicles
You will also need to have your vehicle registered with Quebec "if independent" I do not know the cost but I do know it is yearly.
And in Quebec if you are considered a Heavy Vehicle you will need to log and cross the scales, have DOT card, and daily inspection report and be a member of a random drug testing consortium. "it does not matter what country you are from, US, MEX, CAN"