02 September 2020

Van Aert Takes Stage 5!

Belgian Wout van Aert dominated the final sprint to win today's fifth stage of the Tour de France.  Look at the great timing I had in grabbing a screen capture of the finish.


That's Dutchman Cees Bol just a couple of centimetres behind van Aert.  What a finish!  Cyclists were reaching speeds of 60 kph (37 mph) in the final hundred metres.  For all that late speed, the rest of the race was slow.  Check out how our prediction fared.
  • Stage 05:  4h 21' 22" (actual), 4h 05' 44" (prediction), 15' 38" fast (-5.98% error)
Van Aert's average speed is given below.
  • Stage 05:  11.67 m/s (42.01 kph or 26.10 mph)
Our prediction wasn't as bad as the one we offered for Stage 3, but I want our predictions to be as good as what we offered for yesterday's stage.  I want to be under 1% error!  This desire allows me to make a brief aside.  Science doesn't care at all what I desire, believe, think, or yearn for.  If I create a scientific model of something in the natural world, like a cycling race, I want the best data and most accurate application of the laws of physics.  For something as complicated as the Tour de France, my students and I can't possibly have enough information to offer a perfect prediction for every stage.  Team strategies, weather, fan disruptions, crashes, call-of-nature breaks, eating, and other such factors are all unknown to us.  And that makes for part of the fun.  If a stage has lots of rain and cycling is slow, I don't mind if our model's prediction is too fast.  I also want to know if we have something modeled poorly, like cyclist power output or aerodynamic drag.

Having written all that, I have ask the following question.  Were Stages 3 and 5 not absolutely BORING until the final sprint?  I don't ask that question as an indirect way of offering an excuse for a prediction with nearly 6% error.  I ask it because the entire stage, which was mostly downhill, lacked attacking cyclists.  Where were the daring riders who dashed ahead in a breakaway, only to cause angst in other teams, who would then feel compelled to chase the attackers?  On the best athletic day of my life I couldn't do what those elite cyclists do.  But as a fan, I want to see more action and fewer slow-moving pelotons.

Tomorrow's 191-km (119-mi) Stage 6 takes riders southwest from Le Teil nearly to the peak of Mont Aigoual.  The first 155 km of the stage is flat as can be.  The final 36 km (22 mi) of the stage, however, will see the cyclists increase their elevation by 1336 m (4383 ft).  That will be some brutal climbing!  Our prediction is given below.
  • Stage 06:  4h 51' 26" (prediction)
What I definitely don't want to see tomorrow is a slow-moving peloton on the flat part and then the climbers taking over at the end.  I want to see more action on the flat part.  Let's see some breakaways!

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