What is Drag Racing?
Drag racing is the 100 yard dash of motorsports. In its simplest form a drag race consists of two cars racing each other from a standing start down a straight track to see which one can get to the finish line first.
However, because drag racing tries to appeal to a wide variety of racers, from beginner to professional, who race with a wide variety of cars, from 70 mile per hour station wagons to 330 mile per hour dragsters, there are a few variations to that simple formula.
Fortunately, the variations are simple too, and once you understand the basics, you’ll be able to learn the variations, and then you’ll understand, and appreciate, the whole sport.
Let’s go through the basics by describing what you would see if you went to Race City Speedway. We’ll describe the racetrack itself, and then talk through the racing that you would see.

The Drag Strip
The racetracks that drag races are contested on are called drag strips. Drag strips can be small and simple local operations or big, fancy, and expensive facilities that rival any sporting venue anywhere in the world. However, they all contain several common areas that are essential to the proper functioning of a race.

Pits
The pit area is where the racers park their racecars, trailers, and support vehicles. Pit areas are usually located on one side of the drag strip (called, strangely enough, the "pit side").
Pit areas in small dragstrips are usually grassed areas, which is OK except when it’s real dry (dusty) or real wet (muddy). Pit areas in bigger dragstrips are frequently paved areas, which is OK except in the summer (hot). Since summer is the prime drag racing season, you’ll see lots of canopies and awnings in the pits to provide shade for the cars and the teams.
One of the unique aspects of drag racing from a spectator point of view is that spectators can walk around the pit area (try that at a NASCAR race and see how far you get!). Since drag racers are almost always working on their cars, a walk around the pits provides some great views of the cars and how they are constructed. Spectators should always remember to stay out of the area right around the racecar and trailer unless invited to come in by the racers.
The roads in the pit area lead to the second part of the drag strip, called the staging lanes. 

Staging Lanes
The staging lanes are where the cars line up to race. Simple enough idea, but even at your local track there can be a hundred cars in several different categories of competition. At national events, there can be several hundred cars competing. So the logistics of getting them lined up to race are not always so simple.
That’s why there are usually 6 or more staging lanes at a track. Cars in different classes get "called" to different staging lanes. You’ll hear the track announcer say something like "Stock Eliminator report to lanes 1 and 2", which means that the cars participating in the Stock Eliminator category have to line up in staging lanes 1 and 2 for their next runs down the track. 

Timing Tower
At the front of the staging lanes (the end nearest the race track), is the timing tower. This is the easiest way to tell how fancy the track is. The newest drag strips have timing towers that look like an office complex. They usually span the race track (the cars go under a tunnel to get to the starting line), have media rooms, rooms for track officials to use during the races, offices for them to use during the week, and luxury suites just like a football stadium. The timing towers at smaller tracks look like a small airport control tower, are usually 2 stories high, and are on the side of the track with the pits and staging lanes.
For quite some time now, drag races have been timed using computer systems controlled by photoelectric beams going across the track. The timing tower is the place where all this high tech equipment is kept and controlled and where the track officials conduct the race.
Once the cars leave the staging lanes, they are on the racetrack itself. The track can be divided up into four main areas: the water box, the starting line, the finish line, and the shut down area. 

Water Box
Prior to making a run down the track, drag racers like to clean and heat up their rear tires (slicks) to get better traction. They do this by pulling into the water box area and doing a burnout, in which the tires spin against the track, getting hot and clean. 

Starting Line
After the burnouts, the drivers will pull their cars to the starting line. Since the idea of a drag race is to accelerate your car as quickly as possible, the starting line is the most important area with regard to a car making a good run. A good starting line is smooth and sticky.
The main focus of everyone at the starting line is the Christmas Tree. The Christmas Tree is a pole with a series of yellow lights followed by one green and one red light on each side. Two small yellow lights at the top of the Tree tell the drivers when their cars are 7 inches from the starting line (pre-staged) and when they are on the starting line (staged).

The Christmas Tree

The next series of larger yellow lights flash to tell the drivers they are about to start the race. The race starts when the green light flashes, and the red light goes on if a driver leaves the starting line before the green light comes on. 

Finish Line
Drag strips are either 1/4 mile or 1/8 of a mile long. All national events are contested on 1/4 mile tracks, as are most divisional events.
There are two main results for each car in drag racing: the elapsed time to go from start to finish (also called its "ET") and how fast the car is going at the end of the run. These results are usually posted on scoreboards on each side of the track after each race.
When a car leaves the starting line, the computerized timing system starts a clock. When the car crosses the finish line, the clock is stopped and the resulting time is the car’s ET. ETs are usually reported to the 1000^th of a second, such as 4.745 seconds.
Just before the finish line, the cars enter the "traps", named after speed traps on the highway. The traps are usually indicated by diagonal lines running across the track. When the cars enter the traps, a separate clock is started. This second clock also stops when the car crosses the finish line. This time is used to calculate how fast the car was going at the end of the race. Speeds are usually reported to the hundredth of a mph, such as 316.38 mph. 

Two parachutes, and a long shutdown area are necessary to stop safely

Shutdown Area
Finally, the area after the finish line is called the shut down area. We are routinely going more than 300 mph at the end of the race.  Even with good brakes and a couple of parachutes, it takes some distance to get a car stopped when it’s going that fast. The shutdown area is frequently as long or longer than the racetrack itself. 

A Typical Drag Race
If you were to go to the drag strip this weekend, you would see lots of cars racing throughout the course of the evening. They would be of all different types and sizes and speeds, but most of them would go through the following routine on every run.

Burnout
Two cars would pull out of the staging lanes and into the water box. They would then rev up their engines, and the rear tires would start to spin in the water. The friction of the tires spinning against the racetrack causes heat and the tires actually start to smoke.

The purpose of the burnout is primarily to clean the tires and to heat the surface of them to make them sticky. Racers like to debate over how long a burnout should be to be effective, but spectators all agree that the longer and smokier a burnout is the better.

A good burnout cleans and heats the rear slicks

Staging
After the burnout, the cars will move forward slowly towards the starting line. When a car is 7 inches from the starting line, its front tires will pass into a photoelectric beam shining across the track. When the tire breaks that beam, the Pre-Staged light on top of the Christmas Tree goes on.
In order to get the best possible jump when the race starts, drivers usually (but not always) want to put just the front part of their tire in the beam. So after they are Pre-Staged, they will usually creep forward very slowly to the next beam which indicates the starting line. Once the starting line beam is broken, the Staged light at the top of the Christmas Tree goes on and the driver knows he or she is at the starting line.

Starting the Race
When both drivers are staged, the race is ready to begin. The race starter will usually wait one or two seconds and then activate the Christmas Tree. The larger yellow lights on the Christmas Tree will blink to let the drivers know the race is about to start. For some categories of cars, all of the yellow lights blink at once. This is called a Pro Tree. For other categories of cars, the yellow lights blink in succession, counting down to the start of the race.
When the green light comes on, the race has started and the drivers can leave the starting line. How quickly a driver reacts to the green light is a critical part of winning a drag race. This is called a driver’s Reaction Time and is measured in thousandths of a second.
If one driver has a quicker reaction time than his or her opponent, the quicker driver has an advantage – in essence a headstart – and can sometimes win the race even with a slower car. This is called a holeshot. Keep in mind that a good holeshot is a few hundreths of a second.
There’s one more light on the Christmas Tree – one that no racer likes to see in his or her lane. The bottom light is red and if that goes on it means the driver in that lane left the starting line before the green light came on and he or she automatically loses the race.

ET / MPH
Once the green light goes on both cars will accelerate down the track towards the finish line. Tracks have scoreboards for each lane at the finish line which will show how long it took the car to go from start to finish (called the car’s elapsed time or ET) and how fast the car was going at the end of the race in miles per hour. Most scoreboards also have some way of indicating which car won the race.
Once the cars cross the finish line they slow down in the shut down area and return to the pits. On the way back, they will be given a timeslip from the track which shows how their car performed on the run.