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Dr. Diandra: The hidden data on accidents and spins at road courses

Michael McDowell's tire carrier Brett Sanchelli draws his strength from his sister Courtney, who was left a quadriplegic after an accident during their childhood.

Whether fantasy racing or behind the wheel, success requires avoiding drivers who rack up a lot of accidents and spins.

But identifying the drivers involved in the most accidents and spins on road courses is harder than at other types of tracks.

A recent history of cautions

Statisticians usually calculate accidents and spins from the caution list NASCAR releases for each race. The sanctioning body classifies the cause of each caution and which cars were involved.

Cautions are up in 2022 relative to last year. The graph below summarizes numbers and types of accidents through 24 races each season.

A stacked vertical bar chart showing a breakdown of cautions by race and type from 2013-2022 after 24 races

I dimmed the competition and stage-end caution bars to highlight what we’ve come to call ‘natural cautions.’ Natural cautions include everything except stage-end and competition cautions.

History exposes trends. For example, the graph shows debris cautions falling from 36 in 2016 to 16 in 2017, when NASCAR introduced the Damaged Vehicle Policy.

The largest cause of cautions in any year are accidents. The 2021 season had the fewest accidents (64) since 1986 — which is how far back I have reliable caution data. We’ve tallied 86 accidents this year.

The 47 spins we’ve had are more than triple last year’s 15 spins. The increase in spins is due to the Next Gen car being harder to drive than the old Gen-6 car. Lack of asymmetry makes the current car much harder to ‘catch’ when it starts to turn.

Although accidents are higher in 2022 than in 2021, they’re lower than 2020, when we had 92 at this point in the season.

Is 2022 really high? Or was 2021 abnormally low?

Road courses are unique

I’m all in favor of NASCAR experimenting with everything from format to schedule — even though their experiments make my job harder. The fewer constants in the data, the more complex the analysis.

The plot below details this year’s cautions by type and race.

A stacked vertical bar chart showing the numbers and types of cautions for the first 24 races in 2022

The Indianapolis road course statistics immediately jumped out at me.

I didn’t need to look up any data to know there was more than one spin in that race. And definitely more than one accident.

Reviewing the race video convinced me that cautions are not an accurate way to measure accidents and spins at road courses. Road courses are long and spread out. Cars can get safely off-track or return to racing after an incident without the need for a caution.

That doesn’t change the fact that there was an incident.

Counting incidents is admittedly subjective. I included only incidents that caused significant position loss or damaged a car enough to force an unscheduled pit stop.

In addition to the incidents on the official caution list, the 2022 Indianapolis road course had:

  • 10 accidents
  • Nine spins
  • Five off-track excursions
  • Two miscellaneous incidents

The one ‘official’ accident, plus the 10 I counted, makes 11 accidents — more than any other track this year. No track has totaled nine spins in one race, either. And the off-track excursions on a road course would be hitting the wall at oval tracks.

I tallied incidents from the other three road courses this year, again based on video.

A table showing the number of Non-caution-causing incidents in 2022

I count 19 accidents and 24 more spins this year than official totals, which makes the increase over 2021 even larger.

Or does it?

Until 2017, the Cup Series visited two road courses each season: Sonoma and Watkins Glen. Uncaptured incidents weren’t as important for two reasons. First, road courses were two races out of 29 or more — from 5.5% to 6.9% of the schedule. Second, the year-to-year variation in the two tracks’ numbers was probably small.

But in 2021, road courses made up 19.4% of the Cup Series schedule.

A table showing how the number of road courses in the Cup Series has changed in recent years

NASCAR replaced four tracks where cautions capture most accidents and spins with four tracks where they weren’t.

The huge increase in spins this year is real. We haven’t had more spins in a season since 2002.

But accident totals are suspect pending going back and counting incidents at road courses in 2021. The drop in accidents from 2020 to 2021 may be due (at least in part) to schedule changes rather than drivers.

Implications for Watkins Glen

The number of uncounted incidents probably doesn’t interest fantasy racers as much as knowing which drivers are most likely to have accidents and spins at road courses.

From my count of incidents at the four road courses run this year, the drivers involved in the most incidents are Bubba Wallace, Ross Chastain, Kyle Larson, Alex Bowman, Austin Dillon and A.J. Allmendinger.

Each was involved in at least five incidents. The number of incidents is greater than the number of races because drivers who have spins or accidents often have more than one in a single race.

Todd Gilliland and Michael McDowell managed to avoid incidents entirely at road courses. Other full-time drivers with minimal road-course-incident involvement include: Martin Truex Jr., Christopher Bell, Tyler Reddick, Daniel Suarez, Chase Briscoe, Justin Haley, Chris Buescher, Ricky Stenhouse Jr. and Corey LaJoie.

Ryan Blaney, currently vying with Truex for the last playoff position open on points, has four incidents at road courses this year.

How does all this information affect choices for Watkins Glen (Sunday, 3 p.m. ET, USA Network)?

Of the list of most-incident-involved drivers, only Chastain has won on a road course this year.

The other three winners are on the least-incident-involved list.