Slowing down carbon emissionsby Stephanie Hemphill, Minnesota Public Radio
Polls show a majority of Americans are concerned about global warming, but it is not clear what we are willing to do about it. One idea under consideration by a state task force is to lower the speed limit on interstate highways.
St. Paul, Minn. — A task force is due to vote Wednesday on some measures Minnesota could take to reduce its carbon footprint. The group has been studying 50 possible approaches to the problem. It's planning to report to Gov. Tim Pawlenty after the first of the year.
Some of the ideas are the energy equivalent of castor oil -- they may be good for us, but they're a little hard to swallow.
The Minnesota Climate Change Advisory Group is considering the idea of lowering speed limits on interstate highways. In the city, the group is talking about dropping speed limits from 65 mph to 55. In the country, the idea is to go from 70 mph to 60.
Back in the mid-1970s, in response to the Arab oil embargo, the entire U.S. had a speed limit of 55 mph. Compared to driving 70, that probably saved 10 percent or more in gas. But more importantly for today's discussion, it saved the same in carbon emissions.
Cars and trucks contribute about one-fourth of Minnesota's greenhouse gas emissions.
The idea of lower speed limits is getting some help from a surprising corner.
"It's something that can be done. You try to look for ways to do things that aren't extremely expensive," said Greg Langford, a member the advisory group.
Langford and his wife operate a small trucking company out of St. Cloud. Two years ago they put speed limiters on their 12 trucks, lowering their speed from 72 mph to 68 mph. They also installed small engines to power the trucks while they're sitting at truck stops. Those two steps have saved 15 percent in fuel, and in carbon emissions.
"We've certainly spent a lot of money to use these technologies," Langford said. "One of the things we found that was the easiest -- or if you want to call it, the cheapest -- way to go was the reduction in speeds."
When asked, people filling their gas tanks in St. Paul said they'd be willing to do their part.
One driver said it was a great idea; another said if it would reduce carbon emissions by about 10 to 12 percent, it would be worth it.
But speed limits aren't simple. John Broadhurst teaches physics at the University of Minnesota. He agrees we could reduce our carbon emissions by driving slower, but it wouldn't make enough of a difference. He said different cars are designed to get maximum efficiency at different rates of speed.
And he points out that driving slower means more time on the road, which could mean more congestion.
And he said people could make better choices about what they drive.
"Do we really need to go to large SUVs, and Hummers and things, to carry one person plus the groceries?" he asked. "People often say, 'Well, I need to take the family camping in the summer, therefore I need an SUV. But they use it for 10 days, and they drive the same SUV around for the rest of the year, you see."
The Climate Change Advisory Group is studying fifty options. Reducing speed limits is only one of them.
Jan Callison is a member of the group, and the mayor of Minnetonka. She said Minnesotans want to do something about global warming; but some things are easier to do than others.
"This particular option of reducing speed limits is really still very much in the position of understanding it better," Callison said. "Understanding what the benefits might be, understanding what the costs might be, understanding how it compares to other options in terms of how much energy we want to put into trying to change people's driving habits."
Today the group will likely endorse the options they can all agree on, reserving the more difficult items for meetings in January. One of the items likely to be delayed is what -- if anything -- to do about speed limits.
- Morning Edition, 12/05/2007, 7:20 a.m.