Nate Silver, the precocious statistician who knew the final results of the 2008 election before it even happened, has taken on the tricky and high-stakes question of why Americans are driving less.
“High stakes” because the decades-long trend in increasing car usage has been a defining force in post-war America–shaping everything from our daily routines to our community structures to our natural landscape. But that trend line suddenly broke downward in 2007 and are now, month after month, U.S. motorists are logging fewer miles. So what brought about the reversal though and will it last? Was it higher gas prices? Or a tanking economy leading to fewer commuters? Or was something else at work — a slow-dawning realization that 50-mile commutes are madness and that life is bit better if we take a more balanced approach to transportation?
Writing for Esquire, Silver built a regression model to tease apart the various causes — and found that gas prices and unemployment alone don’t quite explain the current data:
The model predicts that given a somewhat higher unemployment rate but much lower gas prices, the lower gas prices should have won out: Americans should have driven slightly more in January 2009 than they had a year earlier. But instead, as we’ve described, they drove somewhat less. In fact, they drove about 8 percent less than the model predicted.
So–as we’ve speculated about on this site recently–maybe there is some kind of cultural shift at work here.
But the jury isn’t in yet:
There is strong statistical evidence, in fact, that Americans respond rather slowly to changes in fuel prices. The cost of gas twelve months ago, for example, has historically been a much better predictor of driving behavior than the cost of gas today.
The real test will come as the summer unfolds and Americans have had time to get “used to” lower gas prices.
Gas prices peaked in July of last year. So if Silver’s 12-month lag effect holds in this case, August and September will be telling months. We’ll be watching.
May 7th, 2009 at 4:18 pm
His article doesn’t list all the variables considered but clearly a “depressed state” of mind has taken hold of consumers (especially those receiving 401ks). Some friends have gotten their employers to allow them to work from home but given the large price increases at the pump, I’m still surprised the decrease wasn’t larger. The long term trend is still up and we are more dependent than ever on four wheels than on two and pedestrians are an endangered species in most of the USA.
May 7th, 2009 at 5:07 pm
Curious. I feel like I need to see the original. How does he explain the relatively fast response to $4/gallon?
May 7th, 2009 at 5:34 pm
I think it’s just an asymmetrical response — quicker when price of gas goes up than when it goes down. Would be interesting to get an economist’s thoughts on why that might be the case.
-Jebediah
May 8th, 2009 at 7:36 pm
I suspect this is mostly due to the collapse of the subprime market. With fewer people able to buy their dream homes in the exurbs, they are forced to continue renting, buying smaller single family, or multi-family units, all of which tend to be found in urban areas close to jobs.
Of course, the pin that pricked that asset bubbled was in fact the oil shock, but this would be an indirect affect. Rather than people purposefully changing their behavior, they’re having their behavior changed for them. Since the subprime industry accounted for as much as 40% of the purchase money market and disappeared almost overnight, it might explain the rapid reaction to oil prices.
May 19th, 2009 at 2:29 pm
[...] The poll seems to offer yet another reason to look seriously at what’s going on in America and ask: Are we just temporarily scaling back our appetites during a recession or are we in the midst of a much more lasting cultural and economic shift toward lower consumption habits? “Consumption” in this case is not just buying fewer gizmos and wingdings, but also driving less–which has become a pronounced trend well beyond what one expect from the effects of recession and unemployment alone. [...]