The two times I did the trip by bike, I didn't find the traffic all that bad. It is tough through and out of Montreal, but in places on the 138 it is really light to non-existant. Cars are moving along at a good pace though. It was fine for me. I did the trip two times in the early fall, so the summer peak, might be worse.
What I found late last summer while coming back by car was that several of the bridges that span rivers coming down from the north are missing, leading to long and ugly detours up to the HWY 40 area and back down again. The Bridges were missing from the Quebec end. But after hitting of few of these I went onto the HWY 40 for the rest of the trip. So who know how many in total might have been missing. It looked as though major rebuilding was necesary, so check to ensure that your route is uninterupted. You might think that the few missing bridges were just a fluke, and they may be, but overpasses and bridges have been collapsing in Quebec, which led to an inquiry and an assessment of all such structures, so it is possible to run into multiple affected structures. Indeed I crossed other bridges under construction (and passable) while on the detours.
Last edited by NoReg; 05-12-09 at 09:26 PM.