Mayoral candidate Rocco Rossi’s proposal to revive the Spadina Expressway as a tunnel is short on details (but Wikipedia reminds me that the original Spadina Expressway was tunnelled from Eglinton south to Davenport). The campaign promises that the tunnel “will not disrupt a single neighbourhood, street or family home,” without explaining how. I assume they’d go under the two residential blocks between Eglinton West station and the top of Cedarvale Park.
Let’s look at some possibilities.
The red route (7.9km) takes the path of the original expressway, emerging from the escarpment under Casa Loma and going straight down Spadina. This is not an option which would not disrupt a single neighbourhood, street or family home, but there it is. The purple route (8.34km) goes under the subway all the way from Eglinton West to Union. At no point does it come up to breathe, which seems unfeasible, so we have to put on- and off-ramps somewhere. The green route (7.6km), of my own devising, connects the Allen to the DVP through Cedarvale Park and Rosedale Valley Road. Update: the pink route connects the 401 and Gardiner by linking Black Creek southward along the rail right of way.
For the record, I still think Jane Jacobs was right about the original question.