16 July 2016

Cavendish gets 4th stage win!

Mark Cavendish won his fourth stage of this year's Tour de France.  He won a stage in which riders fought massive headwinds all day.  One report I saw had the head wind nearing 40 kph (25 mph).  The wind killed our prediction, as seen below.
  •  Stage 14:  5h 43' 49" (actual), 4h 53' 25" (prediction), 50' 24" fast (-14.66% error)
I know why we were so off, but I still hate to see so large an error.  We had that same error on Stage 3.  That stage reinforced the idea that we can be off if team strategies' are such as to hold cyclists back.  Today's stage is a reminder that not knowing the weather can lead to a bad prediction.  Check out Cavendish's average speed below.
  • Stage 14:  10.11 m/s (36.39 kph or 22.61 mph)
That is incredibly slow for a flat stage, even a long one.  The slowest average speed the Tour de France time schedule makers considered was 40 kph (25 mph).  To match the time for today's stage, we would have needed to include a 10.7 kph (6.67 mph) headwind on our model cyclist -- for the entire 208.5 km (129.6 mi).  We didn't miss today's stage because of poorly implemented physics.  We missed it because we had no idea ahead of time that riders would face headwinds.  But that's part of the unknown associated with the modelling the Tour de France.

Tomorrow's Stage 15 contains two category-1 climbs and a big HC climb.  The stage features a fast descent to the finish.  Below is our prediction.
  • Stage 15:  4h 22' 06" (prediction)
I like our prediction -- as long as Mother Nature doesn't get in the way!

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