MJF is on the money. NC "left" their low band in place because low band is still the primary SHP radio system statewide, not VIPER....yet. Where there is VIPER coverage, both systems are in use with a fixed multi-cast arrangement in the comm center consoles using trunking mobile units on a power supply in the equipment room tied to a roof top yagi. The troopers use the VIPER portables when out of the car instead of the former VHF high band/low band vehicular repeaters and the VHF portables.
In counties where there is no VIPER, the VHF vehicular repeater is still the workhorse. That will change when all the VIPER sites are operational, when all the comm centers are refurbed/rebuilt with consoles that are trunking (VIPER) capable, when all the troopers have the VIPER portables, and when all the cars have the VIPER mobiles. Meanwhile, back at the listening post, we wait........ and wait........ and wait......... To pre-empt some questions, yes, a few of the comm centers have consoles that are VIPER capable.
Also, the NCEM low band is well beyond past tense. As a matter of fact, several of the NCEM low band base stations west of Raleigh were updated and used to replace some even older NCSHP low band transmitters. The NCEM vehicles may still have low band radios for whatever reasons. Numerous NC cities and counties have had no EM low band capability for several years and some have never had the capability.
And yes, funding, or lack thereof, is the mantra from the NC Ivory Tower of Legislation and Finaglery about the slow down in VIPER buildout progress.
PS: I'm old enough to remember when VA had VSP on low band and was monitoring it on a Motorola Mocom 70 mobile.