Actually, if you follow the links provided you will see that there are several things that are classified as reckless driving. One way to get a reckless citation is 20 over or going 80.
15 over comes from the fact that the speed limit on the interstate is 65. 65 + 15 = 80 = automatic reckless driving. In VA you can go to jail for that even on a first offense.
Also note that they have felony and misdemeanor reckless driving.
46.2-862 MISDEMEANOR RECKLESS DRIVING - SPEEDING 20 MPH OR MORE
ABOVE SPEED LIMIT OR IN EXCESS OF 80 MPH. (C)2 $350 Misdemeanor 1