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Pit stop analytics

By E. Andrew Boyde.a.boyd@earthlink.net

Magic shows are fun because we get to experience the impossible. Still, we know there’s trickery afoot. But what about those times when the magic isn’t magic? When we witness something that’s seemingly impossible but proves all too real? Not only real, but the result of optimization?

Such is the case in the Formula 1 race car pit. If you follow F1 racing, it comes as no surprise that pit stops have been reduced to two seconds. But if you aren’t an F1 devotee, the idea of lifting a car, changing four tires and sending it on its way in a mere two seconds stretches the imagination.

The role of the pit has changed dramatically over the years. For much of racing history it was assumed cars would only stop in the event of problems. Scheduled tire changes or fuel stops weren’t part of the equation. This orthodoxy was challenged in 1982 when an analytically minded race team from the United Kingdom focused in on two important facts. First, softer tires stuck to the track better during turns than their harder cousins, though they wore out more quickly. Second, less gas in the tank translated into a lighter, and therefore faster, car. Calculations showed that time spent changing tires and refilling the tank was more than offset by the improved performance of the car on the track. It’s a calculation any analytics practitioner would be proud of.

Quick stop: Optimized F1 pit teams can change four tires in two seconds.

Quick stop: Optimized F1 pit teams can change four tires in two seconds.

The idea quickly caught on, making pit stops – and their efficient execution – an integral part of racing. Refueling was banned in 1984 out of safety concerns, but reinstated in 1994. During that 10-year period pit crews refined their tire changing skills to the point where the fastest pit stops took a little over four seconds. When refueling was again instituted, the impetus for faster tire changes disappeared since refueling was the bottleneck. That changed in 2010 when F1 racing again reverted to a no refueling policy, setting the stage for lightening fast tire changes.

Achieving a two-second tire change required optimizing the entire process. Engineers took a look at everything from the design of the wheel nuts (one per wheel on F1 cars) to the special, self-positioning pneumatic guns that remove and tighten each nut. They then turned their attention to the pit crews.

Teams of three work on each wheel; one to remove the old tire, one to position the new tire and one to operate the gun. Their moves aren’t left to chance, but are choreographed down to the position of their hands and feet from start to finish. It’s not hard to imagine John and Lillian Gilbreth – progenitors of industrial engineering and pioneers of time and motion studies – standing nearby, stopwatches in hand. They’d certainly be smiling in approval. With two jack operators and scattered observers, as many as 20 people crowd around a car during a pit stop – for two seconds of work.

Optimization brings to mind models and mathematical programs. But sometimes optimization is smart without being sophisticated. And in the F1 pit, it works like magic.

Andrew Boyd, INFORMS Fellow and INFORMS VP of Marketing, Communications and Outreach, served as executive and chief scientist at an analytics firm for many years. He can be reached at e.a.boyd@earthlink.net.

References & Notes

  1. Gray, W., “Tech Talk: Can F1 Pit Stops Get Even Quicker?” Eurosport, April 9, 2013. See also: https://uk.eurosport.yahoo.com/blogs/will-gray/gray-matter-f1-stops-even-quicker-101951154.html. Accessed May 24, 2014.
  2. Examples of fast pit stops can be found at: https://www.youtube.com/watch?v=aHSUp7msCIE https://www.youtube.com/watch?v=Xvu0GlMa3xQ