In NASCAR's infancy, seeing more than 70 cars on the track was always a possibility -- especially at tracks such as Darlington Speedway and Daytona International Speedway. A standard field size evolved along with the sport.
At first, entries gradually decreased due to prevailing economic hardships. Fields that were once 75 became fields of 40 as recent as 20 years ago -- and the number was closer to 30 cars on smaller tracks. At that point, fields were tailored to individual tracks and lacked a consistent method
Those numbers ticked upward to 42 and 36, respectively, until NASCAR -- which had long discussed the need to standardize fields -- implemented a mandatory 43-car field for all three national circuits for the 1998 season and beyond. The first 36 spots are decided in time trials, while spots 37-42 are determined with four provisionals.
The 43rd position is reserved for a former Sprint Cup champion that has not otherwise qualified.