The AMA Superbike doubleheader is a common thing today but the genesis of it really got started at Road Atlanta in May, 1998.
The doubleheader round was not an innovation cooked up by the AMA but by promoter Dan Murphy.
Murphy brought Superbike back to the track after a hiatus and wanted something special for the "Big Kahuna Nationals" that year. Two Superbike races were run instead of just one, setting the event apart from the other events on the schedule. The format was proven to be a huge hit, spurred on by a great first race.
The Saturday race was a classic, with an epic three-way battle for the win. Miguel Duhamel (Honda), Anthony Gobert (Vance and Hines Ducati), and Ben Bostrom (Honda) all fought for the race win on the last lap. Each rider led at one point during the race and all three were motivated to take the win.
After Bostrom led a Superbike race for the first time and held point with two to go, Gobert made a pass and assumed the lead on Road Atlanta's 2.54-mile layout. It looked like he had the race sewn up, but Duhamel took the victory from Gobert with a down-the-hill pass on the last lap. (Ironically, turn 12 is where Duhamel was injured in a recent testing crash.)
As Miguel was making his move to the front, Ben Bostrom had lined up a potential outside pass to catch both Gobert and Miguel at the line. Bostrom got into the red Georgia clay and tumbled at over 100 miles per hour, his RC45 flipping wildly. Fortunately, Bostrom was unhurt.
It might have been the most exciting 15 seconds in the history of the series.
Gobert won the next day in a much more processional race, but the doubleheader bug spread. For 2000, Road America and Mid-Ohio had twin races and now most events are doubleheaders.