Spring 2021 Darlington Race Report

How did the high-horsepower low-downforce package used for Spring 2021 Darlington compare to previous races, especially those with the 550-horsepower package?

Caution- and Lead-O-Gram

There were six cautions in the 2021 Spring Darlington race: two stage-end cautions and four for accidents. Contrary to most races, all of the cautions happened in stages 1 and 2, with stage 3 running caution free.

The Caution- and Lead-O-Grams for 2021 Spring Darlington

We had 10 distinct leaders in the race. I cannot figure out why Reddick appears twice in the legend, but it probably has something to do with a new feature in the lead-o-gram. I’ve identified periods of green-flag pit stops and noted those with dots. That allows me to get a better idea of how many quality leaders we had.

Quality leaders are those who earned the lead. That means they became leader by making a green-flag pass, on a restart or at the race start. It eliminates drivers who led only during a yellow-flag portion of the race. And now it also eliminates drivers who led during a green-flag pit cycle.

Laps Led

You can’t really see the green-flag pit stop laps led because MTJ led 248 out of the 293 laps.

A column chart of laps led for 2021 Spring Darlington showing Martin Truex, Jr.'s absolute dominance

Hamlin, Ware, Reddick and Buescher led no quality laps, hence the 6 quality leaders.

Where Drivers Ran Their Fastest Laps

I like to identify where in the race each driver ran his fastest lap, which I’ve shown on the plot below for 2021 Spring Darlington.

A column graph showing where drivers had their fastest laps for 2021 Spring Darlington

That so many drivers had their fastest laps on the same lap is a consequence of tire fall-off. The fastest laps were usually right after taking new tires.

A number of drivers never got their car better than it was on the first lap of the race. Notably, Keselowski, Austin Dillon and Kevin Harvick were way off. Keselowski never recovered, but Harvick managed to pull a P6 out of it.

Most of the other driver were able to dial in their cars a little better toward the end of the race, but Truex was so dominant that it didn’t help all that much.

Was 2021 Spring Darlington a Good Race?

How does 2021 Spring Darlington compare to previous Spring Darlington races. There were no Spring races from 2015-2019, but we did have two Spring races last year. (One of the very few good thing to come out of COVID.)

One of the things we learned from having two races in close succession was how wildly different races can be at the same track on consecutive days.

Metric5-Year Average3-Year Average2020-052020-062021-2
% Running at Finish85.7387.8487.5092.3189.19
Quality Leaders/100 Laps2.
# Cautions9.010.710116
Margin of Victory (seconds)1.330.902.15under caution2.57
% Cars on Lead Lap51.756.860.059.024.3
GFPPL = Green Flag Passes per Lap

We had fewer cautions than usual in this race, which probably had more to do with MTJ’s dominance and less with the rules package. Numbers of accidents and spins were about the same, too.

The quantity that stands out here, however, is the number of cars that got lapped. Only 24.3% of cars finished on the lead lap. You can see from the graph below that we haven’t seen that kind of dominance in years, although it wasn’t uncommon back in the early 2000s.


Races vary so much that it’s hard to ascribe the quality of the race to the new package. Until there’s more and more consistent data, whether this was a ‘good’ race is pretty subjective.

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