Cautions: A Historical Downward Trend Over the Last Six Years

OK, I know I promised the next post was on engines, but I got sidetracked…

Being the data geek that I am, I was really curious if the decreasing number of cautions was specific to this year.  It’s not:  Cautions have been decreasing since 2005,as the graph below shows.  The squares are the cumulative number of cautions per 100 miles, obtained by adding up all the cautions in a season and dividing by the total number of miles in the races.  (This is a more accurate number than total cautions, given rainouts, shortening races and different venues from year to year.)

The straight line is a linear regression, with a R-squared of 0.87, which is pretty good.  The grey box in the lower right hand corner is what the fit predicts the number of cautions should be if the trend continues.

Of course, someone is wondering what happened before 2005. The trend was totally opposite.

My rationale for going back to 2001 is that this was the first 36-race season.  Not a great reason, but that was pretty much it.  The peak number of cautions was in 2005.  What happened in 2006 that sent the number of cautions down?




  1. Here are some reasons I could think of.

    1. The 2005 Coke 600 had a record 22 cautions due to the track deciding to do a surprise ‘levigation’ on the surface which was popping Goodyears left and right, so that spiked the 2005 season’s caution average.

    2. Ever-increasing number of downforce tracks, where cars are more spread out and less likely to make contact.

    3. Ever-decreasing number of short tracks, where contact and cautions were higher.

    4. The stability of the COT. It generates enormous sideforce and is incredibly stable ever since it was introduced. Hard to turn but stable. We’ve seen drivers be able to make saves that would’ve easily been 360° spins with the pre-COT car.

    5. The increasing number of start-n-park cars. These were usually bad drivers in inferior cars that you could usually count on to spin out or have a mechanical failure during the race and bring out a caution. Well, now they park right after the green so you’ve got only quality drivers and cars circulating the track that rarely make mistakes or fail.

    That’s about all I can think of for now.

  2. NASCAR and Goodyear do not like the drivers belittling the tires after a race in which adhesion lessens significantly between pit stops. Therefore all tires have become hockey pucks. Problem solved…for Goodyear. NASCAR is apathetic and will not lend enough guidance to rectify the situation.

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