Since this is mainly Emergency Services and that tow trucks are not necessarily Emergency Services. How about the idea of having a Heavy Rescue Tow? Make it a combination unit. Integrate a tow truck with a Heavy Rescue sort of similar to Heavy Rescue 401 on TV. I bring this idea up because it could possibly bypass having this unit added into emergency services rather than make it an outside pipe company.
You could either have it as a Heavy Rescue Tow or a Utility Tow. Either way it would basically be the same thing.
Before anyone says it please don't bring up changing of graphics. This idea could possibly open up new calls as a lot of MVA scenarios require tow trucks in real life. Since this is a game this could potentially open up and expand the game.
Perhaps this could also have its own extension and training if possible.