We're all for reducing carbon emissions, but we can't support lowering the speed limit on interstate highways to do it.

The Minnesota Climate Change Advisory Group is preparing to present some of its recommendations to Gov. Tim Pawlenty early next year. The group is studying 50 options and among the ideas is lowering the speed limits on interstate highways. The group is considering decreasing the speed limits from 65 mph to 55 mph in cities and 70 mph to 60 mph in the country.

But we agree with Pawlenty, who says more feasible options may be to encourage the use of fuel-efficient cars, such as plug-in hybrids, or to toughen emissions standards.

John Broadhurst, a physics teacher at the University of Minnesota, says there would be more environmental gains by people choosing to drive smaller vehicles.

He also noted that driving slower means more time on the road, which could mean more congestion in some places. Vehicles at a stand still in heavy traffic are still running and producing emissions.

Certainly, people may choose to voluntarily reduce speeds while traveling. The effort would not only reduce carbon emissions, but can often increase a vehicle's gas mileage and save wear and tear on tires, brakes and other parts.

An Associated Press story reports that a member of the advisory group who owns a small trucking company in St. Cloud has put speed limiters on his 12 trucks dropping the high-end speed by four mph. He also installed small engines to power the trucks while waiting long periods at stops. The two steps have saved 15 percent in fuel, and in carbon emissions.

We say more power to private companies who choose to take those steps. They not only benefit the environment by reducing emissions, but also the owners of the companies by saving money.

When it comes to reducing speed limits on our highways, it's those kinds of voluntary steps we support in the effort to reduce carbon emissions. There are more efficient ways, the use of hybrids and toughening emissions standards among them to reduce carbon emissions that must be fully explored before considering new speed limits.