The ability to record, process and analyze data has proven invaluable for safety engineers by informing their decisions and improving safety developments.

To the casual observer, the 2023 NASCAR Cup Series race at Watkins Glen International seemed to be the safest race of the season. There was only one caution flag and one retirement due to a mechanical issue.

Drivers did not share that same sentiment.

"Several drivers reached out and said, 'Hey, I wanna see my mouthpiece data from the bus stop at Watkins Glen,' which was unusual because those drivers had not crashed and they finished the race," said Dr. John Patalak, vice president of safety engineering at NASCAR, Daytona Beach, Florida.

At the beginning of the 2023 season, NASCAR began offering mouthpiece sensors for drivers to wear during races on a voluntary basis. It was part of a safety data project that NASCAR began with Dr. Joel Stitzel from Wake Forest University's School of Medicine.

"The [mouthpiece sensor] is more like a retainer, and it records linear acceleration and rotational velocity," said Patalak. "It goes into the upper part of the mouth and upper dentition, so it's really well attached to the driver's skull. We can't actually measure the brain with technology yet, but as a segue to that, we measure what's happening to the skull. Then through modeling, we can infer what's happening to the brain."

Normally, officials use this data to study accidents and understand how certain impacts might affect a driver's brain. There were no crashes to study at Watkins Glen, but the mouthpiece sensors showed troubling data from the bus stop chicane, a notorious section of track with high curbs and high speeds.

"As they went through that chicane, it was very violent," said Patalak. "We looked at the mouthpiece sensor data and [saw] a really big increase in the number of recorded events per race—meaning the number of times their head exceeded the threshold to trigger."

The mouthpiece sensor data was so convincing that NASCAR officials made the decision to...

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Photo by Chris Owens, courtesy of INDYCAR