Friday, July 9, 2010

Tour de France stage length statistics by decade

I was watching VeloCenter where Scott and Todd were droning on and on about how long today's stage of the Tour was: 227.5 km (or, using their preferred units, 141 miles). Now I agree that's a long way to race, but anyone who's followed the Tour for any significant number of years knows 227.5 km is hardly extraordinary. Memories of LeMond racing in the 1980's where the long stage was 270, 280, or even 300 km...

So I decided dig into some real statistics. For stage length, I relied on the excellent web site Memoire du Cyclisme. I found these pages easier to mine than Wikipedia. So I wrote a Perl script to download the relevant annual web pages from the site and sweep the HTML for stage lengths.

stage length statistics

First, I plot the data for each year using a log-normal plot. The x-axis describes stage length, while the y-axis describes the rank of the stage having that length. Each decade in the plot (only even decades to avoid too much clutter) is then represented by a curve. The median stage has a y-value of zero. So if stages in a given year are longer, the curve for that decade will be further right. I added the plot for this year's Tour as points.

You can see a clear trend leftward. Stages have been getting shorter. But while the long stage this year may be relatively short, the points for 2010 fall generally on the curve for the previous decade (2000-2009).

There's a lot of information in that ranked distance plot: maybe too much. To simplify, I extracted the median stage for each decade, along with the average maximum distance for each decade. Again the trend is clear. The median stage length has been dropping. But more dramatically the truly monster stages from decades past has been diminishing.

stage length statistics

A lot of this probably has to do with the changing nature of the Tour. The Tour started to sell newspapers. In news stories, you can't see speed, it's hard to grasp speed with words alone. But distance: that's another matter. Reading of epic journeys as riders travel more than 400 km in a day, starting not long after midnight and finishing just in time for the paper's deadline, is inspiring. People wanted to read each day not only of who won, but more importantly who'd survived.

These days, it's all about television coverage, and television only has so many hours. Make the stages too long, and riders slow down, finish times become less predictable, and the Tour becomes logistically more expensive. So while fans still demand the organizers expose the riders to an adequate amount of suffering, the days of stages over 250 km seem to be over. Want a death march? Check out Race Across America. The Tour is about speed.

So what next? Will the trend continue? Or will the Tour hold firm at its current length. I may be old fashioned, but I like the long stages. The average rider can, with a bit of training, do 200 km in a day. Certainly it makes the Tour more inspiring if the pros do at least a similar distance. It makes the race epic in a way it wouldn't be were the stages more comparable to a typical US race.


gregclimbs said...

this is awesome as one could also look at those plots and explain (without doping) the average increase in speed of the tour over the years...

djconnel said...

It would be interesting to plot avg speed versus avg stage length and see how the curve is shifting with time.

Certainly you'd expect a time component. In addition to rider physiological factors, equipment and roads have gotten much better since the early days of the Tour, and with the use of race radios the past year, coordination among riders has improved.

So stage length has obviously been an issue, but a lot of factors change decade-by-decade.