2021 Sonoma Race Report

Hendrick domination continued at the 2021 Sonoma race. But how come no one is talking about the record carnage?

Lead- and Caution-O Grams

As usual, here are the caution- and lead-o-grams for the 2021 Sonoma race.

The caution- and lead-o-grama for 2021 Sonoma

Looking at the lower graph first, there were a lot of lead changes during green-flag pit stops, but most of those maintained the lead even after the cycle was over. That makes for seven leaders and seven quality leaders.

2021 Sonoma Cautions

The caution-o-gram shows 8 cautions for 18/90 laps, or 20% of the race run under yellow. Three of those cautions were competition or stage-end cautions, but there were four accidents. That’s unusual for Sonoma at least, recently.

Accidents

Here’s a vertical bar graph showing the number of accidents and spins from 1989-2021 at Sonoma. The box chart at right shows the median and the extremes.

The number of accidents and spins at Sonoma from 1989-2021, normalized to a race length of 90 laps. At right is a box plot showing the median of 2.4

In the last two years we ran this race, we had no accidents, so four accidents is something of a step up. It’s definitely above the median value of 2.4.

But what’s really striking is the number of cars involved in accidents at the 2021 Sonoma race. We set a record!

The number of cars involved in accidents and spins at Sonoma from 1989-2021, normalized to a race length of 90 laps. At right is a box plot showing the median of 3.8 from 1989-2021
Reminder: These are normalized to a race length of 90 laps, so they’re not whole numbers when races are longer or shorter.

We don’t usually see cars torn up the way we saw cars torn up last Sunday at Sonoma. Normally, I plot these for 2000-2021, but since this was a record for that timespan, I thought I’d go back a little further. Sure enough the largest number of cars involved in accidents before last Sunday was almost 10, in 1993. And if you include accidents and spins, the maximum was a little more than 10, in 2010. We had 14.7 cars involved (15 in 92 laps) in 2021 Sonoma.

A new! track! record!

Are drivers just getting more aggressive the closer we get to the cutoff? Or are people making more mistakes?

Or both?

Lead Laps and Completions

Despite the record number of cars hitting other cars and barriers, The 2021 Sonoma race had the highest percentage of cars finishing on the lead lap since 1989.

A vertical bar graph showing the percentage of cars finishing the race on the lead lap.

The last three runnings of this race saw and average of 60% of the cars finish on the lead lap. We got 89.2% for 2021 Sonoma, which tells us that, although cars were damaged, many of them were repairable.

Green-Flag Passing

There was more green-flag passing than either of the last two runnings of this race. The number of quality green-flag passes was comparable to that in 2017, where there was more overall passing.

A stacked vertical bar graph showing the number of green-flag passes. broken down into quality (for position) and non-quality passes.

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