A 50-kilometre tunnel under the 401. Seriously?

The 401 through the middle of this region is one of the busiest stretches of road on the continent, and the Premier’s answer to it is a tunnel: roughly fifty kilometres long, 19.5 metres wide, three decks, one eastbound, one westbound and one for transit, from Mississauga to Scarborough.

The province has hired WSP Canada for $9.1 million to find out whether that is possible. Field work started this spring and the feasibility study is due in early 2027. It will also look at alternatives, including an elevated highway. What it will not do is say what the thing would cost, because nobody in government has; the outside estimates run to $55 billion and two decades of construction.

The case for is the case for the 413 with the geography removed: there is no room to widen the 401 through Toronto, so the only way to add capacity is under it. The case against is the same induced-demand argument every new road in this region faces, plus a price that would buy a great deal of anything else. A poll in January found 28 per cent of Ontarians in favour and 45 against.

Nobody has ever built a road tunnel this long. That is either the reason to try or the reason not to.

Sources: CTV, the $9.1-million feasibility study · CP24, Ontarians doubtful · CBC, the province explores feasibility · Toronto Life, the Premier still wants the tunnel