Reaction time?

[GoPed2009]

hope it helps, dont kno if its all right but its stuff ive learned here and there

Once both vehicles are staged, the "tree" is activated and the first amber colored bulbs on both sides of the tree light up. Then ½ second later the next amber bulb lights up while the first amber bulb goes out. Another ½ second later the last amber bulb lights up. And one-half second later the green bulb lights up signaling the drivers to start the race.

the tree counts down at .500 second (five tenths) intervals. The reaction time announced is the time that the vehicle took to move off of the starting line compared to when the last amber bulb lit up.