Highway 401 Transit and Auto Tunnel

JasonParis · Jan 6, 2026

With the ETR having happened, I still think that it would make more sense for the 410 to replace the 403 to the QEW (Oakville) instead of having the interlined bit of the QEW/403 through Halton. The 403 can just be from Burlington to Woodstock.

lenaitch · Jan 6, 2026

crs1026 said:
The logic is certainly there, considering that at the time I'm sure 4 lanes seemed like all there would ever need to be. Six lanes? Inconceivable. (Reminds me of the expensive 100 MB hard drive that I thought would never need upgrading.....)

The question then becomes, were the 500 and 600 series classifications designated at the same time? If so, the 4 might be more a pigeonhole that a designation based on lanes.

- Paul

(I forgot to hit 'post' yesterday or the day before)

As far as I know the 500/600 (and 800) series have been around since the 1950s. It is possible that 400 was just a decision. It could have as easily been 300 but maybe they want to hedge their bets on how many primary King's highways there would eventually be.

I also have understood the QEW to be designated 451. Maybe whatever system they use (used) to manage provincial highways didn't like non-numeric designators. There are number of named roads, particularly in the north, that are the responsibility of the MTO and all have numbers, usually in the 7000-series.

lenaitch · Jan 6, 2026

nfitz said:
There must be other examples. The 80+ km Sultan Industrial Road comes to mind (part of which became Highway 667 in the 1970s).

There are a couple - the Caramat Industrial Rd. come to mind as well. They are different from Hwy 407 in that, Under the Public Transportation and Highway Improvement Act, they are not provincial highways; they remain private roads that the public has access to (and the MTO subsidizes the maintenance costs).

I don't know if the part between Hwy 129 and Sultan was ever part of the Industrial Rd. It served the village which was originally a section on the CPR. That portion might simply have been a provincially maintained road in an unorganized territory before being promoted to a secondary highway.

nfitz · Jan 7, 2026

lenaitch said:
I don't know if the part between Hwy 129 and Sultan was ever part of the Industrial Rd. It served the village which was originally a section on the CPR. That portion might simply have been a provincially maintained road in an unorganized territory before being promoted to a secondary highway.

Yes, that's entirely possible (or probable). I kind of just assumed, as it was numbered 667, several years after the Sultan Road opened.