NASA TT Passing Rules: Where, When, and How

Time Trial traffic management is the skill nobody practices and everybody needs by session two. The rules themselves are short; the craft is in how the fast half of the grid uses them. Both below.

The formal rules

TT runs as an open-passing group under the NASA CCR's HPDE regulations (Sections 6 and 7 apply to TT competitors explicitly), frequently combined with HPDE 4. Practical translation: passing is permitted anywhere the session allows, cooperative driving is mandatory, and the CCR's "safe and controlled" standard is enforced with TT-specific teeth.

The teeth: more than two wheels off (or both wheels on one axle off simultaneously) deletes your session time. A spin past 80 degrees does the same, and either one with a passenger aboard ends your passenger privileges for the day. A pass under yellow costs the session minimum, potentially the event, potentially the license — with the TT Director holding discretion if the flag call itself was wrong or you were avoiding a collision.

Grids are set by best prior lap ("running grid"), which is half the traffic solution by itself: the field sorts by pace, so most passing happens at big closing-speed deltas between cars that expect it.

The craft

Give the point-by early. TT convention keeps the point-by even in open passing — not because it's required everywhere, but because ambiguity is slow for both cars. A clear early point costs you nothing; a hesitant one costs you both a corner. This is also the etiquette that gets noticed: your incident count and cooperation are exactly what the license review looks at.

Being passed is a competitive skill. The rulebook scores your fastest lap, not your ego. Lift early on the straight, stay predictable, lose half a second once — instead of compromising three corners fighting it. The drivers who defend in TT are the ones still confusing it with racing; the TT vs HPDE piece covers that mindset shift.

Plan your gaps. The lap that wins the day usually starts with deliberately dropping back on the out-lap to buy clear air. Watch the grid ahead of you: if you're behind someone half a second slower, one cool lap creates the space for three clean hot ones. Session craft like this is most of what separates a tidy first TT weekend from a frustrating one.

Know the track's passing zones anyway. Open passing doesn't mean equal-quality passing everywhere. Passing into a heavy braking zone with a cooperative car ahead is free; a lunge into a technical section costs both cars and flags you to the Director.

If you're coming up the HPDE ladder, all of this will feel like HPDE 4 with consequences — which is exactly what it is. Full onboarding in the complete guide.

FAQ

Do you need a point-by in TT? Session rules vary by region and run group; the enforced standard is cooperative, safe passing per the CCR. The practical answer: give them, expect them, and never force a pass on a car that hasn't seen you.

What happens if you pass under yellow? At minimum your session time is gone; the Director can escalate to event disqualification and license action. The only outs are an erroneous flag call or collision avoidance, at the Director's discretion.