Below are a few examples of Flag and Light Signals that Marshals will use to communicate with you whilst on the circuit :-
Green The track is clear and open.
Yellow - Slow your pace, NO OVERTAKING, be extra vigilant for a possible incident ahead. The track will remain open, but there is some kind of hazard that could cause a problem. If the yellow flag is waiving, the hazard is immediately ahead. Overtaking and resumption of full speed is not allowed until you pass (a) a subsequent, occupied flag station where the yellow flag is not displayed or (b) a green flag. An example for a yellow flag might be a crashed car that is off the track and being moved out of a run-off area. The yellow flag means to reduce your pace (60-70% of normal speed) so you are in complete control of your vehicle; it does not mean stop or slow to a crawl.
Red - NO OVERTAKING. The track is closed, most likely due to a crash or some other hazard that needs to be cleaned up. Slow your pace and then leave the track when you reach the exit point. it does not mean stop or slow to a crawl.
Blue - If you are impeding the progress of other cars on track you will be shown the blue flag. Move over and accommodate other cars passing you at the next safe opportunity.
Red / Yellow Stripes - Oil or Debris has been deposited on the track surface. Proceed with care over the next section of track.
Black - If the black flag is pointed directly at you, it means that there is something going on with you or your vehicle that may be a safety concern. Move off the racing line in case you are leaking fluids. Leave the track when you reach the exit point. Go to the Assembly area and report to a member of staff or Pit Lane Marshal.
Driving Standards / Track Limits – Used on some events (not all) to warn that driving standards / etiquette is falling below an acceptable standard, For example driving beyond the edges of the track as defined by lines, cones or rumble strips etc. Some circuits will impose a penalty for multiple infringements.
Chequered - End of the Sighting Laps, session or day, and the track is closing. Leave the Circuit when you reach the exit point. This flag means come back to the paddock at your normal pace; There is no need to slow way down; just come on in at your regular pace.