According to Michael Daly :
Chris Lewis wrote:

At least in Ontario, 90km is very rare.

??? Hwy 69 and a couple of others (6 south Hamilton? anyway, not too uncommon.)
vary between 80 and 90 on different sections. I think it depends on who the
locals voted for.

But even if you are at 90, it's still easy to figure out time - do the calcs as
for 100 and add 10%.

BTW - it isn't divided that determines whether it's 100 or less - it's
controlled access (though every controlled access hwy is divided). I think the
determinant in deciding between 80 and 90 is the frequency of access -
more farm roads = 80, fewer farm roads = 90.

With few exceptions (historical naming reasons, eg: the QEW), only
400-series highways are 100km/h, and 400-series is defined as
"controlled access", "divided" (eg: very wide medians or concrete
barriers), and likely 4 or more lanes.

90 is for important long-haul arteries out in the boonies with very
little access. Parts of 17, 69, 11, much of 115 and a small bit of
6 south (I was on it last week), for example, qualify. Much of the
DVP is 90km too (it'd normally qualify for 100km, but it is, I think,
too congested/narrow/curvy for MTO's taste at 100km).

[I suspect 115 will get upgraded to 100km once they finally finish
all the upgrades. May or may not be renamed to 4xx.]

80 or 90 km highways with "too much" access are hideously dangerous.
11 and 115 were both deathtraps until they started putting in
dividers, fences and "go the other way" bridges.

90 is sufficiently rare that it's a surprise to see it on a road
you've not been on for a while. 6 south surprised me ;-)
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.