Their current fleet of radios may be doing the job for them, and as far as infrastructure goes, probably much simpler. In a disaster it is possible for a standalone repeater to hold up when compared to a multi-site system. KISS.
On the other hand, in the past (for instance, when we had the hurricanes pass through the area that done a lot of damage around 10 yr ago) I have heard Red Cross come across our local HAM repeaters requesting an update for our region (Those of us with the more higher end Motorola handheld fire radios had all the local HAM repeaters and the common simplex frequencies programmed in, because you never know, but that was before narrowband antiquated the radios). I suppose they probably employ several radios on different bands in order to maintain interoperability with more localized areas.
However theirs is owned by the City of Charlotte and is operated by Charlotte Fire Communications personnel.
They call it Field Comm One when they dispatch it.
They use it for mass incidents, land and water incidents.
They have the capability to communicate with any agency that is in the UASI counties or counties that surround Mecklenburg County.
The unit also has both satalite and Viper radios for communications statewide.
I have seen the unit from inside and out and it is very nice and well built.
The State Highway Patrol has a mobile command center as well.
It is built on a tractor trailer chassis and has the capability to provide communications for SHP Events and disasters.
Unlike the Charlotte Fire and the Red Cross units it takes a Class A commercial drivers license to drive this unit and it is only operated by telecommunicators that have been trained on the operation of the unit.
In Salisbury at the EH Dole chapter (where I'm a member), most of our OPS take place via cell phone. We do have access to the trunked system for Rowan County / Salisbury City, as well as access to other radios when the situation is warranted such as a major disaster. There are a number of us who maintain our own radios just for this purpose, and our DST (Disaster Services Technology) group maintain a cache of radios and VSAT equipment. But for normal day to day operations, or responses to the "norm" such as structure fires, we coordinate via cell phone/text. Here in Rowan County when needed or requested we get a text from Rowan 911, exactly like the fire departments do, we call them & find out what's needed.
The link posted earlier and the info in it is correct, but use of those freqs/channels under normal circumstances is sporadic at best. At least around these parts anyway.