We need 5 run groups: 2 for students, 2 for licensed drivers, 1 for instructors. Anytime we drop a group, it is the instructor group, and we ask them to slot their driving time into one of the experienced groups. This is done to maximize track time for all.
We are pretty flexible on run session lengths, mostly at away events. The run groups are not set in stone but are often replicated because they fit our needs. This season's schedule is heavy at NHMS and light on "away" events. As others have pointed out, we do run longer sessions at the away events. At WGI, we ran 30 minute sessions. Tremblant restricts the amount of cars on track to 30. Without that restriction we could have had slightly better use of track time. That said, we still ran a 'modified' schedule with longer sessions.
The first NHMS event this year did have longer sessions. 30 minutes each, I believe (but I reserve the right to be wrong (I don't have my files in front of me now)). In any event, student registrations were very light and we were able to accommodate all students into a single group. Actually, we had a dual-driver student team so one of the students ran in one of the licensed groups. That did NOT go well and we will not be repeating that process.
One solution to increase run session length would be to reduce the amount of run sessions. We've (or at least
I've) considered it before. There are trade offs. On one hand, longer = better for experienced groups (to a point). Less time clearing the track, more continuous time behind the wheel, and theoretically more "clean" laps. On the other hand, miss a session due to a car issue, and you've lost a lot of time. Then, of course, there are several of "our" cars that are lucky to complete a 22 minute session. :LOL:
A single full-course yellow lap to begin each run session is a good thing, and I expect it to continue. In addition to the reasons given above, ther eis also the likelihood that you may have adjusted something on your car in between sessions and in doing so screwed yourself. Not that I know any racers who have left the paddock with lug nuts finger-tight, oil caps missing, a missing brake pad, or unlatched hood pins.
Of all the options and suggestions mentioned in this thread, opening up another passing zone or 2 at NHMS would be most likely, but there really isn't much room to do it. Baby steps...