BikeMath

Some observable trends in Portland bike commuting:

5 degree increase in temperature: 10% increase in ridership
5 degree decrease in temperature: 25% reduction in ridership
First Rainy-Ass Day in Awhile: 50% reduction in ridership
Gas Costs More Than Beer: 60% Increase in ridership, 10% increase in drunk ridership
5 cent reduction in price of gasoline per gallon: 35% reduction in ridership
Tour De France with Lance Armstrong in it: 20% increase in ridership
Tour De France without Lance Armstrong: no discernible change

Where can you go for pithy observations of bike commuting trends and minutiae? That's right, Badinia.com!

Well, it's available at no cost to you, at any rate.