Mar 20th, 2011 by T.C..
During Sunday’s Jeff Byrd 500 at Bristol, there was a sequence of pit stops in which it was shown on TV that Jimmie Johnson was actually passing cars on pit road. There was some question and discussion about how it could be possible that he would be able to pass cars and not get caught for speeding. In accordance to NASCAR’s rules though, what Johnson and a ton of other drivers do is totally legal. They’ve found a loophole in the system that allows them to legally speed on pit road.
I’m going to attempt to explain how this works, so try and follow along. If you get lost at any point, leave your question in the comment section below and I’ll answer. Here goes…
NASCAR measures the speed of the cars on pit road by segment times. Each pit road is broken into several timing segments. The car’s transponder along with timing & scoring sensors at the beginning and ending of each segment determine segment times. At legal speeds, it takes a certain amount of time (X) to complete a segment. If a car completes a segment in less time than it should legally take to do so, then that car is guilty of speeding. Follow so far?
Okay, now that we’ve established how it works, here’s how they can legally speed. The smart drivers and crew chiefs have figured out at each track where the segments are. They then pick a pit stall in between two timing lines. This means a driver must maintain legal speed until he crosses the timing line before his pit stall. Once over that line, he can hit the throttle and drive into his pit stall over the legal speed limit. Once the pit stop is complete, he can then race out of his stall at a speed over the legal limit, until he reaches the next timing mark, where he then must be at legal speed. What allows for the speeding? The pit stop.
Because a four tire pit stop takes 13ish seconds, it screws up the time for that specific segment. When you take the time it takes for the driver to complete that segment, and add to it the time it takes to complete a pit stop, you’ve got an amount of time that will be way over the legal segment time. Still follow?
I’ll give you an example with some ridiculously hypothetical numbers. Let’s say we are at California, where pit road is 2200 feet. And for our example, let’s say there are ten timing segments (I don’t know how many there are exactly). That means each segment is 220 feet. If pit road speed is 45mph, that means a car can travel 66 feet a second. At 45mph, a car will complete a legal segment in about 3.3 seconds. Now add to that a pit stop that takes 13 seconds. That means a car will be in that specific segment for over 16 seconds. There is no way to illegally “speed” in that segment now. A driver could technically do 200mph into and out of his pit stall and not be guilty of speeding. Crazy right?
So, because pit road speeds are based on these timing segments, and not what a car’s actual speed is at any point on pit road, one can actually legally speed. That’s why Jimmie Johnson was not busted for speeding at Bristol, and why any number of other drivers who do it regularly don’t get busted either. It’s actually quite an art form, although it can be a little unnerving as a pit crew guy to see the car accelerate right before it enters the pit stall.
There are a ton of really smart people who work in this sport, and no matter the rule, somebody will always find a way around it. Welcome to NASCAR.