What does RT mean in drag racing?

You have probably heard of the term RT (Reaction Time) when it comes to drag racing. However, most people don’t understand what the term means and why it is essential. Whether you are a beginner or seasoned drag racer, you already know that a good reaction time could give you the win.

Understanding RT

Before we start discussing how to get good reaction times, we need to understand a straightforward term – the Christmas tree. Although drag racing seems simple, know that the starting line is the difference between winning and losing.

We need to take a closer look at both the starting line and reaction times to understand how the two interact with both the driver and each other.

The tree

At the starting line, the first thing that comes to mind is the tree. Three major components make up the tree. At the very top, there are two sets of yellow bulbs on each side. It is commonly referred to as the Pre-Stage bulb because it indicates that a driver is approaching the starting line.

The second set of lights on the tree is referred to as the Stage bulbs. These lights will indicate that the driver of the vehicle is on the starting line and ready to race.

The next section contains three starting signals that usually light up in a sequence. In Sportsman classes and racing classes, these lights are half-second apart. All three parts make up what is referred to as a full tree.

However, understand that some drag races will use a Pro Tree. The Pro Tree has all the three sections lighting up simultaneously. In our case, we will concentrate on the full tree model that is quite common.

The green and red lights are the most instrumental when it comes to drag racing. The green comes on when the driver has left the starting time at the appropriate time. However, the dreaded red light will turn on when there is a foul start.

The Reaction Time Countdown

As stated earlier, the full tree counts down in intervals of half-second. The cycle goes as follows: Amber on, delay, amber off, next bulb. Now comes the most critical part.

The reaction time commences when the third amber lights up. This means that you get a half-second delay before the green light turns on. To most drivers, the half-second delay is enough to get them that perfect start.

The reaction time will stop immediately the car leaves your starting line. Let us take a closer look at the starting line for a better understanding.

The Starting Line

The starting line includes two pairs of photocells that detect when your car tire interrupts the light beam. The photocells are directly linked to the tree: both the stage and pre-stage lights. Since most tracks have a rollout, drivers get a distance of about 6 inches before their car exits the starting line.

Your reaction time will start when the third amber light up and stop when your car’s tire leaves the starting line. A long rollout means that you have to react before you see that green light.


Getting a good reaction time ensures that you have better chances of winning the drag race. However, it takes a lot of experience and patience to achieve perfect reaction times.

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