Truckers are stockpiling dirty diesel engines

In 2007, new EPA regulations that mandate cleaner diesel engines took effect. The new engines reduce particle emissions by up to 98% over the previous generation and cut Nitrogen-oxide emissions in half.

But they increase the cost of trucks by $12,000, or about 10%. In addition, truckers (consumers of the new engines) expect higher maintenance costs and worse fuel mileage.

Predictably, the new regulations caused a big increase in demand for 2006 engines and trucks,

Truckers seeking to beat the price increases made 2006 a record year for truck makers. More than 373,000 big-rig trucks were built in North America, says Ken Vieth of A.C.T. Research, which follows truck sales trends. The tally easily topped the previous record of 330,000 trucks in 1999.

But next year, Vieth predicts "a production drought," with sales falling by more than 40% to 220,000 as trucking firms hold off buying to see how the new clean-diesel trucks perform. ...

The cost to truckers goes beyond new big-rig purchases, according to Moskowitz. The new fuel costs 5 cents to 10 cents more per gallon to refine and may produce lower fuel mileage. The new engines weigh more, further cutting mileage. "Over the long run, their increased costs will be passed on to the shippers and ultimately, the consumers," Moskowitz says.

Both the 2006 boom, and the 2007 bust were predictable with simple supply-demand analysis, especially since a similar regulatory change occurred in 2002.

For policy makers, this points out yet another disadvantage of a command-and-control approach to clean air. Mandates from Washington have to be phased in, and this gives consumers an incentive to stockpile old, cheap, but dirty engines so they can use them in the future. Instead of telling producers what to produce, or consumers what to consume (by picking technologies, like ethanol, to subsidize), tax what you don't want (pollution) and let the market decide how best to reduce it.

Bottom line: How many economists does it take to screw in a light bulb? None--the market will do it.