I think they use Nextel for some truck to truck comms. I have to hand it to TDOT on the implementation of the help crews in Nashville. I listen to them 5 days a week. They are usually the very first on the scene and help keep traffic moving by getting break downs, fender benders and the such out of the way so traffic can resume flow. The use of the camera system allows them to dispatch a call usually before the call comes in that there is a problem. Good job TDOT, and the to the crews that help keep things running as smooth as possible, thank you.