I have a better idea, end all mandates of all truckers. The supply chain is too important, most truckers are vaccinated, and truckers aren’t the cause of covid infections. It’s a mandate that has no basis in science.
of course there is no specific trucker 'mandate'; rather, there are entry criteria requirements for unvaccinated persons entering Canada. By the by, for some reason you chose to ignore the following 2 waldo posts - here take another opportunity to comment on them - yes?

Canada's largest trucking company is TFI International Inc.. => the ending of the vaccination requirement exemption for cross-border truckers had been announced by the federal government on Nov. 19 and took effect Jan. 15; as of Jan 15, Canadian truck drivers must be fully vaccinated if they want to avoid a 14-day quarantine upon re-entry from the United States. The United States imposed the same rule on American drivers a week later on Jan. 22, with Canadians who are not fully vaccinated barred from entry to the U.S. and vice versa.
Vaccination at TFI is not an issue at all. The vast majority of TFI's Canadian drivers are inoculated against COVID-19.
one key nugget to add: TFI CEO advised that the small number of unvaccinated truck drivers working for TFI have been restricted (by TFI) to domestic Canadian routes that don't enter the U.S..