As other cars zipped by at 70 mph or more, Mike Papin and his wife, Joann, kept rolling along just below the 65 mph limit as they made their way from their winter home in Florida to a summer place in Vermont.
They've typically done six or seven miles above the speed limit during the annual migration, but with gasoline prices roaring toward $4 a gallon nationally, Joann suggested they ease off the pedal during the 1,500-mile drive this year.
"I read somewhere that around 62 or 63 was the best speed to drive to make the most of your gas," she said.
Drivers have known for years that throttling back is a sure way to improve gas mileage, and the Papins are among those who are consciously slowing down to save. Several airlines have adopted the same tactic, adding a few minutes to flights to save millions on fuel.
But most drivers still appear to be winking at posted speed limits because they say their time is worth more than the gas they'd save by slowing down.
Kelley Goodman, an upstate New York therapist, says gas prices haven't yet gone high enough to justify slowing down.
"I know it could save some money and I really should. But I'm always running late," Goodman said as she pumped $3.80-a-gallon regular unleaded into her Honda Accord.
Researchers say today's cars are most fuel efficient at speeds between around 30 and 60 mph, and mileage drops sharply at speeds above 65 as engines work harder to overcome wind resistance that rises exponentially. If drivers were forced to slow down — and lower speed limits were enforced — the thirst for fuel could be significantly reduced, which could ease prices.
Recent surveys show that many drivers have changed their habits to cut fuel costs, but the changes tend to be ones that bring immediate gratification — such as using the Internet to find stations with the lowest prices and putting less gas in the tank instead of filling up, said Larry Compeau, executive officer of the Society for Consumer Psychology and an associate marketing professor at Clarkson University.
"If you buy a more fuel-efficient car or find cheaper gasoline, those things are right in front of you," Compeau said. "Whether you do 65 or 55 is much more nebulous. There's no way for you to immediately see the impact."
Based on recent highway traffic volume trends, throttling back to 60 mph from 70 mph would likely reduce gasoline usage between 2 percent and 3 percent, which is about what happened when the 55-mph limit was imposed in the 1970s, said David Greene, a senior researcher at the U.S. Energy Department's Oak Ridge National Lab.
"We're talking about a 2-to-3 percent reduction in demand, which would mean a much larger percentage reduction in price, maybe 10 percent," Greene said.
Tom Kloza of the Oil Price Information Service in Wall, N.J., agreed that a 2-to-3 percent cut in demand likely would reduce prices. But, he notes, in past years price spikes were usually linked to refinery shortages while this surge has been tied more directly to crude oil prices.
"I don't think there's a particular downside to conservation, but that doesn't mean that if we cut back on our gas consumption, that the price of crude oil worldwide is going to drop," he said.
The idea of slowing down to save fuel isn't new. President Richard Nixon and Congress imposed a national speed limit of 55 mph in 1974 during the Middle East oil embargo against the U.S. Prices at the pump quadrupled from about a quarter to more than a dollar in places, and long gas lines were a common sight.
States later were allowed to set 65-mph limits on rural interstates.
Congress repealed the national speed limit law in 1995, and today 32 states have limits of 70 mph or higher on some parts of their highways, according to the Insurance Institute for Highway Safety. Texas already has an 80-mph limit on some roads and Utah's legislature has voted to raise the limit to 80 on part of one interstate.
At least two states — Alabama and Connecticut — have considered reducing speed limits, but those efforts haven't gained much traction. And despite the benefits, there seems to be little appetite in Congress for a new national speed limit.
"We haven't been able to find anyone to champion it," said Clayton Boyce of the American Trucking Association, which is advocating for a 65 mph national speed limit.
Some truckers are slowing down anyway as the average price of diesel heads toward $4.50 a gallon.
"I'm saving between $100 and $200 a week by cutting back from 72-73 mph to 60-65 mph," said Dennis Sheridan, who owns an 18-wheeler and hauls freight on a contract basis throughout the Northeast.
Sheridan is an owner-operator, paying for his own fuel and other expenses and getting paid for each load delivered. And so far, slowing down hasn't hindered his ability to make deliveries on time.
"If you're going from say, New York to California, you might lose an hour over the run," he said. "But on the East Coast, what are you going to lose, 10 minutes? You know as soon as you step on it you're going to hit traffic anyway."
Drivers who work for a trucking company have no incentive to slow down because the companies cover fuel and other costs and pay the drivers by the mile. The more they drive, the more they earn.
"I haven't slowed down at all," said Earl Wood, a regional driver for Allen's Foods, a Seaford, Del.-based food production and distribution company that specializes in poultry. "It's not worth it to me."
Other company drivers have no choice but to slow down. Boyce says many of the trade group's members have dialed back the maximum speed on their rigs to save money on diesel.
Con-Way Freight of Ann Arbor, Mich., is one of them. The company in January lowered the top governed speed of its 8,400 tractors to 62 from 65 mph.
The relatively small reduction will save roughly 3.2 million gallons of diesel fuel annually — about $13.3 million worth at today's prices — while increasing the time it takes to move freight between cities within the company's delivery regions by about 20-30 minutes, said Con-Way spokesman Gary Frantz.
"We found that it will have very little impact on our operations," he said.
While Con-Way has voluntarily cut back its trucks' speed, some states have considered the idea of mandating lower speeds for all vehicles.
Last year, Connecticut State Sen. Thomas Gaffey introduced a bill that would lower the maximum speed limit there to 60 mph from 65 mph, but it died in committee.
State Rep. Thad McClammy of Alabama — which has a maximum speed limit of 70 mph — this year proposed a measure that would enable his state to easily ratchet down speed limits when fuel prices are high and raise them when prices are low.
His bill would create a state commission with the power to adjust speed limits rather than having to go through what can be a cumbersome legislative process. McClammy said his bill doesn't appear to have the support it needs to pass this session, but he'll keep pushing.
"There is no realistic option on the table from anyone else to deal with the situation, and this legislation is going to look better every time the price goes up at the pump," he said.