Dks01 At one time, Canada Post used to encourage even urban letter carriers to use public transit when on the job. A former co-worker whose father was a letter carrier even said that monthly transit passes were provided to encourage the practise.
Times seem to have changed. Here, they do part of their route, say one block or so, then it’s back to the Canada Post vehicle for more mail. With the carriers now doing all of the flyers that are distributed, it would be virtually impossible for them to carry everything, including small parcels, for the entire route; they’d need a mule, or to look like the Incredible Hulk.
I suspect this was a cost-cutting measure, as some retired. Instead of keeping the same number of carriers, they had one carrier deliver mail to more routes, allowing the use of one of their vehicles to carry the subsequent batches of mail. Of course, that’s just my guess.