[blamazon]

These have been common in North America for large trucks operating in snowy places for decades - school buses, dump trucks, etc.

Handy because you don't have to stop/get out/interrupt service - just flip a switch and you've got improved traction!

[nimbius]

as a large truck mechanic i can say theyre okay and degrade roads casually because operators suck at learning how to use them.. in real winters like Alberta the drivewheel is either frozen to the motorized arm all the time, or glides like a ballerina against a wall of ice from the tire. this is a solution for a problem of casual issue, like climate change in the south usa perhaps :)

[userbinator]

It seems like one of those things that's probably more common than you think, given that you'd have to pay very close attention and know what you're looking for to see them in use.

[cortesoft]

Also something I would never see living in Los Angeles.

[sethammons]

However, living two hours away from LA in the San Bernardino mountains, our school buses were running these in the 80s and 90s.

[dtgriscom]

I've seen them mostly on local (Boston area) fire trucks.