I'm fairly certain it hasn't been brought up (Sorry if i'm wrong about that), but why is it necessary to tow a vehicle just to change a tire? I believe the RP involved with depending on a garage to do Auto Tech is totally necessary for the most part, but the one exception at least should be being able to change a tire on the street.
I've definitely thought about some more mobile mechanics for auto tech, and how cool it would be to be able to work up to a mobile rig, but for this post, just the tires.
Changing tires is simple. Most everyone who drives can do it. A junior mechanic can definitely do it. So instead of a junior mechanic having to puppet request for a tow, for a vehicle with one blown tire, why not just have the dang junior mechanic go out and change the tire himself.