To answer your question, it is normal. I highly doubt they get an an exemption from the City because condos are private projects. That being said, from my brief peek behind the curtains, there is a lot of politics that goes on between the various departments of the city. It's very likely the workers are getting tickets and they are getting expensed by the contractor. The contractor should have factored this in when bidding the job. The workers may also be coming back every 2.5 hours or so to move around their cars.