Street design is a finnicky thing. The City's standard clearance is 1.8 metres, and the bare minimum for new sidewalks is 1.5m. That's still pretty tight, this guy took about a minute to gingerly squeeze through this narrow channel:
Even with 1.5m though, sometimes they can't make it through. I measured exactly 150cm exactly between the tip of the 'nose' of hydrant and edge of bike rack (hope nobody parks their bike there when the plow needs to get by!)...
...but the clearance isn't straight! The slalom of three minimum-width clearances doesn't leave enough room for larger sidewalk plows to go through.
Eventually, one of the smaller, more nimble plows without the salt spreader on the back to go through a few days later.
This kind of detail can be easily overlooked in the consultations on street design, especially when many of the consultations happen throughout the Summer. Very often there are also last-minute changes to put in an extra utility box in what ends up to be a very inconvenient location.
The 1.8m rule applies not only to sidewalks, but also to bike facilities, like the bike cutout at Bank and McLeod.