Hi Rick,
All of the vehicles at the PoCo that I work for are equipped with VHF Radio's.
We've always used radio communications as far as I can remember, especially for vehicle to vehicle comms.
Cellphone coverage around here is too dodgy with all the mountains and things getting in the way of a decent signal.
I can also "patch" into the local phone network here if I have to.
Don't forget that radio communications have also come a long way in the last few years as well.