Monday, June 23, 2008

A painless plan to reduce petroleum demand

In their efforts to avoid finding a short-term solution to the current tight petroleum supply situation, no politician is going after the lowest hanging fruit.

We have the Republicans focused on drilling for more oil, with a 5 to 10 year implementation window, and the Democrats wishing upon a star for a renewable energy miracle cure (not yet defined) with a 20+ year waiting period to begin meaningful production.

But there is an easy option to reduce gasoline demand by up to 5% that neither party has recognized. The solution can be implemented with immediate results, requires no new legislation and no new Federal spending. All it will take is enforcement of current speed limits on the Interstate Highway System.

For drivers in Wisconsin, the limits are already enforced to some extent. Leeway is typically given up to 10 mph over the limit, and anyone going faster is at risk of a ticket. It is not that way elsewhere.

On my recent trip through Virginia and Maryland, I estimated that I was is the slowest 10% of drivers when traveling at 5 mph over the 65 mph limit. The average traffic speed was probably somewhere above 75 mph. I saw only one motorist pulled over in those states for an apparent speeding violation. Slow all these drivers down to the speed limit nationwide and there would be a dramatic savings of fuel.

I was unable to find data on fuel economy versus speed at anything above 75 mph, so I extrapolated the following data from for higher speeds.
In general I found that fuel economy drops by about 7% for every 5 mph of increased speed over 60 mph.

I also determined that 32% of the 5 trillion miles driven annually in the U.S. are on Interstate highways. Therefore, reducing average Interstate speeds by 5 mph would reduce U.S. annual fuel consumption by 2.3%. That is about 3 billion gallons of the 150 billion gallons of gasoline used in 2006. A drop of 10 mph would mean 6 billion less gallons of imported gasoline being used.

These fuel savings estimates are obviously gross estimates. But the estimates do provide an idea of the magnitude of fuel savings that can be achieved by slowing highway traffic. This will mean reduced demand with our current supply. Hence, lower gas prices.

Reducing speeds on Interstate highways can be achieved as Wisconsin has demonstrated. But it is a matter of priorities, usually at the discretion of each state's governor to direct their state highway police to enforce the current speed limits. Congress could help lure them in that direction by providing financial incentives for better enforcement.

I call this a painless plan because it will be to me. At least until they enforce speeds closer than 5 mph over the limit.

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