The rarely used wave-by rule is set to be implemented for the first time at the Sandown 500 in a move that will keep more cars in contention.

The wave-by procedure was used during the height of COVID-19 at the Bathurst 1000 but this year will be the first time the rule has been implemented outside the Great Race.

Supercars released its Sandown 500 supplementary regulations this week, which detailed the procedure.

The rule differs from a “Lucky Dog” in that every car a lap down will be allowed to get its lap back, rather than just the first car a lap down.

Per D10.2.13.4 of the supplementary regulations: “Cars one (1) or more laps behind the leader as per Rule D10.2.5.11 will be instructed via RMC and via the timing screen to pass the line of Cars including the SC when between the exit of T4 and flag point 5.8, just prior to T6.”

It continues: “Lapped Cars that have not crossed the Safety Car Line 1 (SC1) timing line prior to the SC crossing Safety Car Line 2 timing line (SC2), will not be eligible to pass the SC. After passing the SC, Pit Lane will be closed to the lapped Cars until they cross the control line on the racetrack.”

There is a caveat, however. If the race director does not consider track conditions suitable, the wave-by rule will not be implemented.

That could be the case if the weather deteriorates to the point where the race director believes it is unsafe.

It is also noted in the regulations: “Decisions made in respect of this unlapping procedure are not subject to protest.”

Another stipulation in the regulations could have bigger implications for how the race plays out in the final laps.

The rule means there is provision for Supercars to take lapped cars out of the fight for the win by repositioning them to the back of the field by transiting the pit lane.

Per D10.2.15.1: “Should a SC deployment end eight (8) laps or less from the last lap of a race, or ten (10) minutes or less prior to the time certain finish time of a race as published in the Supplementary Regulations or as amended by the Stewards, any Car that is one (1) or more laps behind the leader must reposition itself by driving through the Pit Lane so that it is not in front of any Car that is on the lead lap.”

Whether these rules will extend to the Bathurst 1000 has not been confirmed.