Didn't notice? Don't be too hard on yourself.
"[Efforts] haven't been as successful as they could have been," admits Ken Butcher, who runs the National Institute of Standards and Technology's Metric Program for the U.S. Department of Commerce in Maryland. "A lot of good efforts got frustrated along the way."
During Gerald Ford's presidency the Metric Conversion Act was signed in 1975, making it the policy of the United States that it would move toward the metric system voluntarily.
Today, under the banner "Toward a Metric America," people like Mr. Butcher are still trying. He'd like you to embrace the metric system. He's even got a whole week - National Metric Week runs through Saturday - to try.
Maybe he could celebrate his efforts by downing some suds at Campus Pollyeyes pub in Bowling Green, where a small but important piece of the metric revolution is under way. There, he could sit down next to college students and enjoy a one-liter "supermug" of beer.
The kids love the stuff, but that could be the beer talking. Manager Jackie Panning still isn't sold on the metric system.
"The metric system's all metric to me," she said. "I'm not one for change. I like everything American. If it's here, it should be American."
Historically, most in this country have agreed. The dilemma of using a uniform system of weights and measures has faced the United States since its beginnings. John Adams and Thomas Jefferson spoke favorably of the metric system after it was developed by the French and started to spread after the French Revolution of 1789, but it wasn't legalized until 1866. Even then, little changed from the conventional system of feet, gallons, and pounds.
The Metric Conversion Act of 1975 hoped to settle the issue once and for all and led to a huge, public push toward joining the rest of the world as a metric power. Subsequent legislation in 1988 required federal agencies to do more of their business in metric and made it the preferred system for trade and commerce, if not for average Americans.
The result of this voluntary transition has been a hodgepodge of products. You buy milk in gallons, but water in liters; aspirin in milligrams and meat by the pound. It's maddening for metric advocates, who see their system as easier to use in daily life and global trade.
Larry Stempnik, a member of the U.S. Metric Association from Milford, Mich., said the whole system's just better. He remembers his first metric moment in grade school: "We had to convert millimeters to centimeters. Basically, all you do is move the decimal point," he said. "I thought to myself, there must be something wrong. It's too easy. ... I still remember that vividly to this day."
The argument goes that most conversions would go unnoticed by the public and would help U.S. companies compete in a climate where the European Union has set a deadline of 2010 to go metric-only.
"The average American consumer basically doesn't care whether they buy their mouthwash by the quart or by the liter," Mr. Stempnik said. "If [we] did change ... within a couple of weeks, nobody would care."
Foreign nations have gone metric successfully to varying degrees.
Canada has converted for many purposes, including temperature in weather reports, speed limits, and road signs. Great Britain changed its scales in supermarkets in 2000. In Ireland, highway signs went metric earlier this year.
There have been some snags along the way. For example, Englishman Steve Thoburn famously was dubbed the "Metric Martyr" when he was convicted in 2001 of selling bananas by the pound in violation of European regulations.
Who knows, maybe locals here would do the same. People like Peggy Dion aren't big fans of the metric system and no legislation could make them.
"Personally, I don't know the metric," said the owner of Toledo Driving Schools, who finds driving around a metric Canada quite the challenge.
"When I go to Windsor, I have to figure out kilometers for speed and I'm going, 'Oh no!'●"
And buying gas by the liter? It's enough to make her head spin.
Think of all the changes we'd have to make to the American way of life if we went totally metric. What happens to our beloved Quarter Pounders at McDonalds? Foot-long hot dogs? Or worse, the game of football?
"What to do with third and 1.67 meters to go? That would be a little bit hard for the coaches," joked Doug Pearson, head football coach at St. John's Jesuit High School.
That's not to say it couldn't be done. Track and field went metric years ago. Forget about running the mile anymore; they usually settle for 1600 meters (31 feet short of a mile). Still, it came at the cost of expensive renovations to track facilities. And now, field event results are supposed to be given in metric on the collegiate level, leaving even some competitors confused, said Kevin Hadsell, director of track and field and cross country at the University of Toledo.
"They say the winning long jump was 6.04 meters and nobody knows what you're talking about," he said. "...Even the kids, they don't know what it is."
A few people have even bigger, philosophical problems with the metric system - like the fact that it's a decimal system based on 10s. Or, as Gene Zirkel of Long Island likes to put it, based on the "accident that you and I have 10 fingers."
A system based on 12s - you know, 12 inches to a foot, 12 items in a dozen, 12 hours on a clock, 12 tones in a musical scale - is much, much more to his liking as chairman of the board for the Dozenal Society of America. (Annual dues: one dozen dollars.) What makes that number so good is its factor-ability, how easy it is to divide by other numbers.
"To change to metric would be a change in the wrong direction. It would enshrine a mistake that the French made," he said. "Not one country in the world has ever adopted metrics voluntarily."
That leaves Mr. Stempnik to fight his crusade one person at a time - starting with himself.
"In my car, I have a display in there that displays the temperature. I always have it set to metric. When I was out yesterday, it was 32 degrees Celsius. I know that's a pretty warm day."
What about directions? Does he ever give those in kilometers?
"I've done that in the past, but most people find it confusing."
Contact Ryan E. Smith at: