I was just at the All-Star Race on 5-21-16. Didn't do too much scanning on VIPER P25 or Charlotte UASI P25 TRS.
The analog NASCAR freqs were active without much DMR/TRBO. Mostly listened to NASCAR 1/11 and Race Control. There were some instances when Digital noise was heard instead of FM radio traffic. Drivers/Spotters are still operating in FM mode.
Sitting in the parking lot on the way out I monitored VIPER P25 Talkgroup 51963 Statewide Events Charlie 1. NCSHP was using this talkgroup for traffic control.