Pro Tree

A Pro Tree is a drag racing starting system where all three amber warning lights flash on at the same time, followed by a green "go" light after a brief delay.

In drag racing, drivers don't just floor it whenever they want to start. Instead, they use an electronic starting device called a Christmas Tree, which looks like a tall traffic light with multiple colored bulbs. The Pro Tree is one specific way this starting system can work.

Here's how a Pro Tree works: First, both race cars pull up to the starting line and get positioned properly. Once they're ready, all three amber lights on the Christmas Tree turn on simultaneously. After exactly 0.4 seconds (sometimes 0.5 seconds), the green light comes on, and that's the official start of the race.

The Pro Tree is much more challenging than the other common starting system, called a Sportsman Tree. With a Sportsman Tree, the amber lights turn on one at a time with pauses between them, giving drivers time to get ready and anticipate when the green light will appear. The Pro Tree gives no such warning - it's just amber lights, short pause, then green.

Professional drag racers and experienced competitors typically use the Pro Tree because it tests their reflexes and reaction time more severely. Drivers need lightning-fast reactions since they can't predict exactly when that green light will come on after seeing the ambers.

The goal is to leave the starting line as close as possible to when the green light appears, without leaving too early (called a "red light" or "foul start"). A perfect reaction time on a Pro Tree is considered 0.000 seconds, meaning the driver began moving at exactly the moment the green light turned on.

Most weekend racers and beginners start with the more forgiving Sportsman Tree before advancing to the demanding Pro Tree system used in professional competitions.