Nerd porn alert: Seattle Transit Blog has combed over the numbers in a recent, much-hyped Sightline report that found gasoline consumption was up in Washington State last year, the first such increase in a decade. (Typical reaction/interpretation : "People are logging more miles on the highway!")

But, as STB found after digging in to the numbers, it's not that simple. Yes, gas consumption (as opposed to "driving"—a distinction that I wish more people would make, since fuel efficiency also correlates to fuel consumption) is up, but barely :

After a decade of per-capita declines, 2009 saw a tiny uptick of 3 gal/year for the average Cascadian, a 0.7% increase.  Overall consumption rose 2%, while diesel consumption (a key indicator of freight traffic)  fell by 10%. While Washington and Oregon saw per-capita increases of
STB calls the report "overly sensationalistic," and while I do love Sightline's work, I have to agree. Take a look at this graph below, taken straight from the report:



That red line looks pretty alarming, doesn't it?

Now check out STB's own graph showing the same statistics, this time annual rather than weekly:



Shown this way, the uptick in Washington's blue line is barely perceptible.

The report does show some interesting trends. As STB notes, an increase in gas consumption during a downturn shows that gas usage is extremely price-sensitive and "that this price sensitivity is not well-correlated with economic trends." I.e., people will use more gas even during a recession if the price falls low enough.

Simultaneously, cuts to transit agencies nationwide are pushing Americans back into their cars. Here in Seattle, Metro is contemplating cutting 400,000 hours of service next year alone. Without a reversal of those trends—higher gas prices and more funding for transit—we can probably expect to see a steady, if slow, increase in gas consumption for the next several years to come.