I have instructed at 3 Audi club events under the new passing rules so I know precisely what they are. Below is the relevant text from a document that the chief driving instructor sent to the instructors before the November Sonoma Raceway event, the first that we did under the new rules.
Some of these may be overridden at the discretion of the chief driving instructor. For example, at the January event at Thunderhill all passing was to the left. The long straight between T13 and T14 is a passing zone. T14 is a right hander, which would suggest that the car being passed should move to the left, signal left, and let the overtaking car pass on the right. However, coming out of T13 is generally where faster cars want to pass and the momentum of the car being overtaken puts it on the right side of the track. So it makes sense to pass on the left there.
2.10.5. Let - by/Passing
Let-by/Passing areas and rules shall be clearly defined (in writing if possible) to event staff, all drivers, on-track and classroom instructors, students, and corner workers. These rules shall be strictly enforced.
Advanced student groups and Instructor groups may have additional passing areas as safety allows at the discretion of the Chapter. Instructors participating in any run group must comply with all passing rules applicable to that run group without exception.
A passing vehicle must receive a signal from EACH vehicle being overtaken. EACH vehicle allowing a pass must provide the signal to EACH overtaking vehicle. In groups where turn signals are used, the turn signal will remain on as long as the driver of the vehicle being overtaken wishes to be passed and can be passed in a safe manner.
It is strongly preferred that the passing vehicle goes offline to complete the pass. In general, offline is defined as the side of the track that is the direction of the next corner. Pass on the right if the next corner goes to the right. Pass on the left if the next corner goes to the left.
Let-by/Passing is ONLY allowed by a clearly defined signal from the driver of the car being overtaken. The turn signal (blinker) is used to signal the pass. The turn signal indicates the position/direction that the overtaken car will maintain. The driver of the car being overtaken is required to facilitate the pass by adjusting their speed and position if necessary.
Hand signals (point-by) may be used only in vehicles that do not have turn signals. The hand signal (point by) is given by the driver of the vehicle being overtaken pointing to the side that the passing vehicle should use to make the pass.
In the case where an improper signal that conflicts with established passing rules is displayed, the pass signal will be waved off and no pass will be executed. VIOLATIONS must be handled aggressively by event management, with offenders black-flagged and warned, perhaps deprived of track time, and if necessary, ejected from the event! Let-by/passing signals are an invitation to pass, but NOT a requirement. The pass must only be initiated if it can be completed safely within the designated area(s).
Let-by/passing protocols will become standardized for all ACNA HPDE events. It is recognized that exception situations may exist and the first priority responsibility of each Chapter Event Management Team is to run safe events