NASCAR Photo-Finish: What happens behind the scenes from the driver’s point of view in Kansas-style finishes

No driver was left as heartbroken as Chris Buescher after last Sunday’s race in Kansas. He was just feet away from getting his first win of 2024 before Kyle Larson showed up to foil his day. He ultimately finished 0.001 second behind the Hendrick Motorsports driver, producing the closest finish ever in NASCAR history.

Speaking on the Backstretch Banter programme, he revealed the scenes that unfolded after the race ended and why he trusted the official result. He said, “We all learn things about how things are viewed. How things work there in the end. Of course there is the camera system. That was the ultimate word. We leave the transponders at what time and the score says.’

“They are transponders up to a thousandth of a second that we use every week for all other important measurements on the circuit.” He supported the regular use of transponders and reiterated his confidence in them, saying there was no room to question the verdict. Notably, the transponders put Buescher ahead of Larson on Sunday according to a report from Fox Sports.

However, the margin of error on these pieces of technology is +/- 0.0015 seconds. There are uncontrollable scenarios where the angle of the car or the position of the transponder on the car could activate it earlier or later than when the finish line is actually crossed. This makes images the best choice to rely on during such close-cut finishes.

Detail of the camera system and transponders used to determine race finishes

The camera system used by NASCAR is the same as the camera system used in Olympic events and other major sports. It consists of a wafer-thin line and a high-speed camera. Any object that moves beyond the line is captured by the camera at several thousand frames per second. Computer software is then used to stitch these images together to create a completely real-time image of when the object hits the line.

The transponders, on the other hand, are mounted on the car near the center section of the chassis. Timing lines on the racing surface indicate where the car is compared to the finish line. So when the car crosses the finish line, the transponder is automatically activated by the timelines.