This is something I support for many reasons. Firstly, they don't help reduce congestion over the long run. The fundamental law of congestion, which has been supported by evidence over and over for more than 50 years, says:

people drive more when the stock of roads in their city increases; commercial driving and trucking increase with a city's stock of roads; and people migrate to cities that are relatively well provided with roads

Changes to transport infrastructure like investing in bus systems, subways do much more to relieve congestion anyway. Everyone benefits from improved air quality.

Do I need to mention climate change?

We only have so much money to invest, I say we put it into the most effective areas.

This is already being walked back:

“Of course we’re funding roads,” Guilbeault said. “We have programs to fund roads, but we have said — and maybe I should have been more specific in the past — is that we don’t have funds for large projects like the Troisième lien that the CAQ has been trying to do for for many years.”

The federal government also wants to encourage “active transportation,” which means getting people to walk and cycle.

Don't just encourage it.

Feds need to incentivize people and invest in programs to support it. Bypass Premiers who oppose, and directly fund municipalities who want to build out their active transportation networks.

From my point of view it's not something that should be under their jurisdiction anyway so why were they financing it in the first place?