With gas prices climbing, one Michigan lawmaker says its time to roll back the speed limit.
A Democrat from the east side of the state has introduced a resolution in the state house urging the federal government to enact a 55 mile per hour speed limit nationwide.
The government did just that in the 70’s during the oil crisis setting a 55 mile per hour speed limit to conserve gas.
That went up to 65 miles per hour in the 80’s, and was lifted altogether in the 90’s allowing states to set their own limits.
So far there has been no vote on the resolution.
The problem with this poll, and the 55 MPH speed limit resolution in particular, is that the slight mileage improvement that would result from a lowered speed limit will do nothing to change the price of gas. Not in a noticeable way. Sure, you may save a few bucks personally, and all of that savings will add up. But it’s not going to do much to increase the supply of oil/gasoline.
The number I usually seem to hear about the mileage benefits of a 55 MPH speed limit is “up to 15%.” So let’s say, for the sake of argument, that it really is 15% instead of the 5-10% that “up to 15%” probably really means.
If you’ve got a vehicle that gets 30 MPG and you drive 12,000 miles a year, you will burn about 400 gallons of gas getting wherever it is that you go. Up your mileage by 15% and you’ll be getting 34.5 MPG, saving yourself about 52 gallons of gas. At $4.00 a gallon, that’s 208 dollars, or about $4 per week.
You aren’t going to be buying many extra groceries each week for $4, and gas prices aren’t going to shift much (if at all) because of a tiny decrease in demand.
Meanwhile, gas tax revenues will fall, as will the profit of gas stations and oil companies. This decreased revenue will actually give governments and gasoline suppliers an incentive to RAISE prices to make up for lost income.
Recall that when a county-wide initiative to conserve water in the Atlanta, GA area succeeded in lowering water usage by 30%, the country hiked water rates to make up for the lost revenue. If water usage goes back up, do you think the country will lower rates accordingly?
Here’s a hidden cost to drivers: Driving 12,000 miles at 55 MPH takes about 218 hours. But if you drive 70 MPH, it only takes 171 hours. In other words, to save $4 each week, you’ll need to spend 54 extra minutes driving each week. $4 for 54 minutes comes out to somewhere in the neighborhood of $4.40 per hour. Would you work for $4.40 per hour? Would you give up 54 minutes of family time or free time or sleep each week for $4?
The actual savings (and time cost) experienced by most drivers will be far less, as most people drive a large percentage of their miles on roads other than highways. So maybe you’ll save $1.75 per week. Is that worth lowering the national speed limit?
Personally, I spent the past three tanks of gas driving 65 MPH on the highway instead of my normal 70. I’m shifting back up to 70 for the next three tanks and will see if I notice any difference in my mileage.
I encourage people to do some math before deciding to go forward with this. If someone feels strongly about driving 55, I have a suggestion for them: Drive 55. No one’s stopping you.
Can I drive 55? Sure. Do I want to? I don’t know for sure, but I doubt it.
Do I want to have to? Not a chance.
UPDATE: Bram correctly points out that the federal government did not set a 55 mph speed limit in the 1970s. They actually set a new limit that the states were required to adopt if they wanted their national highway funds. It was a de facto federal speed limit, though Washington couldn’t just set the limits in each state on their own.
(Cross-posted from MichiBlogger.)