# Canadian 'dopers, Freedom Convoy? **URL:** \ **Category:** Politics & Elections\ **Created:** [February 10, 2022, 12:07am UTC](https://boards.straightdope.com/t/canadian-dopers-freedom-convoy/959186 "2022-02-10T00:07:49Z")\ **Posts on this page:** 1\ **Showing post:** 408
**Author:** ![DavidNRockies](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/davidnrockies/32/6279_2.png) [@DavidNRockies](https://boards.straightdope.com/u/DavidNRockies)\ **Post date:** [February 18, 2022, 3:13pm UTC](https://boards.straightdope.com/t/canadian-dopers-freedom-convoy/959186/408 "2022-02-18T15:13:34Z")
@Gorsnak put a bit more truck-specific info on the subject … here: > [@Ottawa Dopers, how are you doing?](https://boards.straightdope.com/t/ottawa-dopers-how-are-you-doing/958960/40): > > 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](https://www.ontario.ca/document/official-air-brake-handbook/spring-parking-and-emergency-brake-subsystem)**. --- _[View the full topic](https://boards.straightdope.com/t/canadian-dopers-freedom-convoy/959186)._