"Once the competitors have both staged, the starter presses a button to start the race. There are two types of tree used. A sportsman tree, used for bracket and handicap racing, consists of each yellow lighting 0.5 seconds after the one above it. The green comes on 0.5 seconds after the last yellow is lit. If the race is a handicap race each side of the tree will have its own timing. A pro tree consists of all three yellows being illuminated at the same time, followed by the green 0.4 seconds later. This type of tree is used for professional and heads-up racing. It should be noted that some tracks run a Pro-style tree for bracket racing during special "Street Racing" bracket events."

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thanks for the information where did you get that? i wanna read the full archive i'm so interested in reading or watching drag racing.







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Also you have to remeber that for certain classes in NHRA events, such as Super Street, a .5 pro tree is used instead of a .4 pro tree. This is mainly because super street is a slower class with heavier cars which are harder to get to react quick enough for a .4 pro tree. It can definitally be done but it is very difficult and requires fairly decent knowledge of how a race car reacts off of the starting line plus some sugar, coffee and, adrenaline.