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Bogging Down The Freeways

Via Eric de Place, the Congressional Budget Office reports that many freeway motorists are adjusting to higher prices at the pump by "making fewer trips and driving more slowly" to conserve gas. The first makes sense, but… the second? Sure, slowing down from, say, 70 mph to 65 can reduce a typical vehicle's fuel consumption by 8.2 percent, give or take. But how many people actually calculate this out in their heads? The CBO Probably only a small minority—but even just a few frugal drivers can have ripple effects all down the freeway, of the sort that seems to be saving fuel:

Such small responses are unlikely to result from conscious calculations. Few motorists would have the information required to gauge their responses so acutely, nor the time or inclination to do so. However, higher prices make drivers pay more attention to speed. The modest reductions in speed suggest that drivers may have responded by easing off slightly on the gasoline pedal or dialing back the cruise-control settings a notch. If only a minority of drivers have that response, their reduced speeds could cause nearby drivers to slow down as well, even if gasoline prices alone would not have that effect.

That's some serious invisible-hand action. I wonder if truckers are the main party responsible here, since various news items have mentioned that they've been intentionally driving at reduced speeds to save on diesel fuel. Maybe that's enough to get everyone to slow down a bit and—however unintentionally—save on gas.

--Bradford Plumer