Yes, this is from the 2011 Convention website.
Run Groups
As soon as we have registration up and running and people start registering, we will be setting up run groups. Typically there is HPDE1 (Green) which is complete newbies or maybe 1-2 track events but not this particular course, HPDE2 (White) which is a few track events (3-4) or a HPDE3 driver who has never done this particular course, HPDE3 (Blue) which is an intermediate level driver who has done probably 5-10 events, HPDE4 (Red) who has done in the range of 10+ track days, and HPDE5 (Black) who are licensed instructors. The number of events you have done to be in a particular group is not written in stone; it is completely subjective