Why?

A quick comment about congressional approval of hybrid cars in carpool lanes: These lanes are meant not for promoting technology but for increasing people-throughput of the road network, itself an indirectly energy-saving goal.

If, down the road, hybrids become hugely popular, we'll see nominal high-occupancy lanes filled with low-occupancy vehicles, and as a result the road will see the same old traffic congestion but with no incentive to consolidate into fewer vehicles. And we can all be certain that, once the policy succeeds in building hybrid vehicles' popularity, their drivers will not gladly reliquish their supposedly temporary carpool-lane privileges. After all, we never expect solo drivers to give up use of existing, unrestricted freeway lanes so that the lanes may be converted to carpool-only flow; rather, we build HOV lanes anew.

Hybrid drivers: enjoy your gas savings, but please don't enter the carpool lane without adding a passenger or three. (And, Congress: I might add that a gas tax increase would more effectively nudge consumers to vote with their dollars for gallon-saving technology.)