Ryan - I don't get how you come up with 120km when your experience seems to suggest that 180km is more than sufficient, even in very cold weather. And you were on major highways rather than a highway with a speed limit of, at best, 90km/h. And you have a low capacity battery that is lower than is current sold by Tesla.
If we are going to insist that Tesla plan for the absolute worst case scenario then that makes it even less likely to get built as putting SCs every 120km will cost 50% more than putting them every 180km. But maybe Tesla doesn't want to run the risk of the bad publicity that would come if someone runs out of juice somewhere between Marathon and White River when it is -35C and a blizzard is taking place.
By the way, the distance from Comber to Woodstock is 185km and Tesla isn't doing anything to shorten that section so presumably they think that is fine, at least for Southern Ontario.
As rypalmer says, with experience few of us have, shorter intervals are necessary in remote areas with rough weather and mostly non-existent communities along the way. I suggested 180km because the cost of 120km intervals might even be double due to the lack of suitable electrical infrastructure. My unstated assumption is that nobody sane will tackle such a route with less than 400km rated range, so about 200km in lousy conditions. Of course some people will try with less capacity. For their sake I hope they so it in the summer so that their odds will improve...
But why should the Canadian prairies or Northern Ontario be different than North Dakota where Tesla has decided that 160km is the right distance, and occasionally a touch longer?
So, good question. Probably they should not be too much different. Both I-94 and the Trans-Canada are mostly twinned for the distance, so highway conditions will be mostly similar. However, I-94 is much more heavily traveled than is the Trans-Canada in that region. Even Winnipeg has much more North-South traffic than East-West. However much those of us on this thread want to see full coverage on the Trans-Canada I think the reality is of far higher need for the Maritimes and far more robust coverage in major cities where there is significant multi-family housing will less-than-ideal charing options. Given those factors I'll guess we'll see coast-to-coast Canada in time for summer 2019, about the same time we'll see coverage to major Alaska destinations.
In the meantime, from Tesla perspective there are serious higher priorities than these, I suspect. Australia, for example has nothing in the west except for a single planned Perth SC. The Middle East needs a full coverage of all the Gulf States, Kuwait to Oman, with Saudi Arabia included. China needs much, much more, as does Japan. Then we cannot forget many European cities needing urban charging...and on and on. Model 3 and Y will necessitate deep SC infrastructure worldwide including places where reservations were taken at launch but precisely zero infrastructure exists, such as Brazil (a trifle larger than the 48 US States), which will be followed quickly by Argentina, Chile and Peru.
There will be some hard priorities for charging infrastructure as Tesla approaches near-mass-market. I don't know how they'll do it, but I hope they find a way to link Sudbury to Winnipeg. After all it will only be ten or so Superchargers, mostly with, say, four stations or even two. We could maybe even crowd-fund this expansion.
