Canadian 'dopers, Freedom Convoy?

[DavidNRockies]

@Gorsnak put a bit more truck-specific info on the subject … here:

Ottawa Dopers, how are you doing?

After doing a bit of reading, the issue is just the air brakes. Semi air brakes are engaged by default, and use air pressure to disengage. If a rig dumps the air pressure in the brake system, all the wheels are locked. There are three ways around this: 1) fire up the truck and disengage the brakes, 2) the really big tow trucks have lines to hook into air brake systems to disengage the brakes, 3) brute force - there’s only so much friction between the tires and the road, and it can be overcome. S…

More specifics are also … here.