Kyle Larson defeated Chris Buescher on Sunday night at Kansas Speedway in what was determined to be the closest finish in Cup Series history.
But at first blush, and in real time, Buescher was shown as the winner on the television broadcast, timing and scoring monitors, and even the infield scoring pylon. The reason is that each car has a digital transponder installed in the same place on the back of every car.
In the case of a photo finish, that is not what decides the winner, but instead it is literally who crosses the finish line first.
But, as was widely contested on Sunday and Monday, what is the finish line, isn’t as straightforward as it appears. For one, when it comes to the last lap, the painted finish line is more ceremonial, which made Sunday even more complicated.
As detailed here, NASCAR uses its cameras and a wire thin laser on pit road as its definitive finish line, using them to create a composite image to accurately determine who wins a race day.
“They’re very close to the same but we don’t go off the accuracy of a painter that paints a line on the racetrack,” Moran told SiriusXM NASCAR Radio on Tuesday. “It’s for a visual for the fans, for the teams to get a visual, but when we get talking this close, we make sure finishes are right like many other sports. We have a laser line that is pencil thin, and this camera takes anywhere from 4,000 to 20,000 frames per second, and that’s how close it is that we see at the start/finish line.
“There are obviously different textures in the asphalt and concrete and by means is that line – not that it was out by a lot or anything like that – but we obviously have a much tighter tolerance on who wins a Cup (Series) race or any race for that matter in NASCAR.”
NASCAR uses a line-scan photo-finish camera and software system called FinishLynx, made by Massachusetts-based Lynx System Developers. FinishLynx has applications in a variety of motorsports series, including IndyCar, Formula 1 and MotoGP, and has also been used in cycling’s Tour de France and in track and field events.
The image from Sunday’s Cup Series finish showing Larson’s No. 5 Chevrolet just ahead of Buescher’s No. 17 Ford is a composite of thousands of tiny, vertical image slices from the start/finish line. When cars cross the line, the camera captures several thousands of precise, timestamped images per second to create the photo-finish result image. The camera is always on; the image-capture process is activated by the first sign of motion at the finish-line focus point — in this instance, the appearance of Larson’s front splitter breaking the plane to complete the final lap.
NASCAR.com
That’s how NASCAR landed on the 0.001 second margin of victory even though the rear transponders concluded a 0.000 victory for Buescher over Larson. This begs the question …
How does NASCAR break a legitimate tie?
In the event of a legitimate tie that even the Lynx camera system can’t determine, the higher finishing position is awarded to the driver who leads more laps. But what if they led the same number of laps? In that case, the driver with the most laps spent in second place earns the tie breaker. If that’s the same, it moves down to third, so on and so forth until the tie is broken.
Matt Weaver is a Motorsports Insider for Sportsnaut. Follow him on Twitter.
