https://en.wikipedia.org/wiki/List_of_tunnels_in_Australia
Despite having a smaller population than Canada, Australia seems to have more urban highway tunnels than Canada has.
https://www.cbc.ca/news/canada/toronto/highway-401-tunnel-study-1.7523029#
HOV lanes & express bus tunnels would help to relieve the surface route.
https://www.cbc.ca/news/canada/toronto/401-tunnel-cost-1.7464404
A truck lane system could also speed up shipping & efficiency.
https://nationalpost.com/news/canada/ford-carney-highway-401-tunnel
https://toronto.citynews.ca/2024/09/25/ontario-highway-401-doug-ford-tunnel-proposal/