dumb question from me but why is that? the engineering, materials, weather, types of vehicles using the roads are similar... why does it deteriorate so much faster in Quebec?
It's a combination of various things. The simple answer is they used cheaper products and products that were less advanced technologically in order to reduce costs, but that's not really a complete answer. The weather thing, while applicable, is a bit of a canard because those same weather conditions apply to adjoining provinces/states that have the same weather as we do, more or less. The more complex answer has to do with the types of contracts the city bought into. Montreal's construction industry was famous for being bought and paid for by the mob, who of course cut corners everywhere, and was absolutely riddled with corruption until the days of the Charbonneau report and the subsequent cleansing. I want to say that was about 10 years ago, but I'm not sure of the timing and can't be arsed to check. The other thing was contracts were offered out to the lowest bidder to provide a service and then go away. With the lowest bidder comes the shoddiest work and the cheapest materials, again to cut costs. Self perpetuating cycle. Also, less controls. Many other places go past the one off deal and instead buy 25-30 year contracts, so that the company that builds it is also required to maintain it on their dime. There's an incentive to do it properly the first time in order to reduce subsequent maintenance and materials costs to the builders which ultimately cost more if the job is done badly at the outset. Quebec doesn't do that, with obvious results. There's other stuff too, but those are the main ones.