Thursday, March 7, 2013

Everybody Has Too Much, But Especially These Places

Here's a fun chart. I literally could play with this data for days.  This one is showing total MSA population on the x-axis with total highway lane miles on the y-axis.  The trendline reveals how consistent this data is.  And why shouldn't it be?  The formulae to determine how many highway(s) lane(s) are needed is incredibly stupid and, well, formulaic.  X number of people gets Y highway capacity.  And the results you see below are extremely consistent:
















Well, except for those four metros that stray significantly from the line.  Which are they?  You know: DFW, Houston, St. Louis, and Kansas City.  Always those same culprits, innit?

The distance from the line would suggest how many more lanes they've been supplied than the population warrants.  While every American metro area could probably do with less total freeway lane miles, these four have WAY too much.  Lemme guess, they're all planning to add more too, right?

When I remove these 4 outliers from the chart, the r-squared value rises from .88 to .94 (closer to 1 means greater consistency, less noise in the system).