1. Late Session Starts
Drivers are not required to be on grid to participate in a session, they may join late.

A. Drivers who start late may be held until every car has gotten a clear lap so as to cause the least disruption to those already on track.

2. Early Session Exit
Drivers entering the paddock before a session ends may keep any times run during that session but may forfeit those times if they return to the track during that session—if the event is one which uses impound procedures.