Racing back to the caution
In automobile racing, specifically NASCAR stock car racing, racing back to the caution is a procedure for drivers after a caution flag is displayed.
The procedure was used in NASCAR racing series when the pace car was deployed as a result of an on-track emergency such as a crash or rain. When NASCAR declared a caution period, racing would not cease immediately; rather, the drivers could continue racing for position until they crossed the start-finish line and received the caution flag. Passes for position counted, and drivers running a lap down (or more) were able to un-lap themselves if they passed the leader prior to the start/finish line.
In addition, if the yellow came out on the final lap, the race would continue until the cars crossed the finish line. An example of this is the 1987 Firecracker 400, when Ken Schrader wrecked approaching the tri-oval on the final lap. If the yellow came out very near the end of the race - so late in the race that there would not be sufficient time to clean up the incident and go back to green before the race had exhausted its scheduled distance - the race would effectively end as the cars received the yellow flag at the start/finish line.
The remaining laps would be run under yellow (with no passing on the track allowed).
An example of this would be the 1984 Firecracker 400.
After racing back to the caution was eliminated, the green-white-checkered rule was implemented to help avoid a race from finishing under caution, particularly in the middle of a lap.