It looks like the AMA has decided to bring back the Semi Finals to the 2014 Supercross season. Also adding 2 more riders to the main events.
http://www.amasupercross.com/rules/pdf/2014/Bulletins/AMA_Bulletin SX 2014.01 Ver2 Rule Changes.pdf
22 racers in both mains
FreePractices
TimedQualifyingPractices
TwoHeatRaces
Two Semi Races
OneLastChanceQualifier
One Final (Main event)
b. In the Heat Races, 1st through 4th will advance to the Main event; 5th through 20th will advance to a Semi.
c. In the Semi, 1st through 5th will advance to the Main Event. 6th through 16th will advance to the Last Chance Qualifier.
d. In the Last Chance Qualifier, 1st through 4th will advance to the main. The 450SX class Main Event will be 20 laps.
e. The first rider across the finish line at the conclusion of a race is the winner.
f. The two Heat Races, Semi’s, Last Chance Qualifier and the Final (Main Event) may also be referred to as "the evening program". g. A Heat Race, Semi, Last Chance Qualifier or the Final (Main Event) may also be referred to as "Race(s)".
http://www.amasupercross.com/rules/pdf/2014/Bulletins/AMA_Bulletin SX 2014.01 Ver2 Rule Changes.pdf
22 racers in both mains
FreePractices
TimedQualifyingPractices
TwoHeatRaces
Two Semi Races
OneLastChanceQualifier
One Final (Main event)
b. In the Heat Races, 1st through 4th will advance to the Main event; 5th through 20th will advance to a Semi.
c. In the Semi, 1st through 5th will advance to the Main Event. 6th through 16th will advance to the Last Chance Qualifier.
d. In the Last Chance Qualifier, 1st through 4th will advance to the main. The 450SX class Main Event will be 20 laps.
e. The first rider across the finish line at the conclusion of a race is the winner.
f. The two Heat Races, Semi’s, Last Chance Qualifier and the Final (Main Event) may also be referred to as "the evening program". g. A Heat Race, Semi, Last Chance Qualifier or the Final (Main Event) may also be referred to as "Race(s)".