IIRC, Glendale (AZ) FD has or had a CERT. I don't know if they still do.
Anyway, in this case, REACT is a group of traffic control specialists from the Maricopa County DOT, who assist munincipalities with extended road closures due to PD/FD/EMS incidents, especially after hours when the city's traffic department employees may not be available. This helps free up local PD's from having to be assigned to it.
I've even heard them working alongside ADOT's ALERT members, when a freeway/highway has to be closed, and they want traffic to follow a specific route along surface streets back to the freeway. MCDOT REACT has the capability to use ALERT's talkgroups on the YRCS, in addition to their own TG('s) on the Maricopa County trunked system.
And, I believe they both also have access to at least the VHF interoperability channels for on scene comms. I've heard at least once an ALERT unit tell another to go to car-to-car, and they didn't pop up on another YRCS TG, and after the flooding isses we had last Spetember when a TS came up through AZ, I heard two ADOT units who were checking the Agua Fria 101 freeway underpasses for flooding come up on one of the VTAC's. (The 101 is less than 200 yards out my back door.)
John
Peoria