Today, Washington's buses begin to join the modern world. It's about time.

This morning, Metro will have new fareboxes on 80 Metrobuses that operate out of the Arlington garage. The new boxes will allow you and me to pay our fares with a SmarTrip card -- those wonderful, jet-age, one-swipe, prepaid pieces of plastic that have sped thousands through subway turnstiles for most of the last 10 years.

For ages, Metro has been promising that SmarTrip was coming to buses, too. Today, the capability will come to only 80 of them -- about 5 percent of the area's 1,500-bus fleet. It's a 90-day test, say the Metro barons.

But if the results are good -- and why wouldn't they be? -- SmarTrip is scheduled to be installed on every bus by spring.

During the 90-day test period, and after it, you'll still be able to pay your bus fare with cash, a token, a pass or a ticket. But you won't be able to pay with pennies on these buses during the test, and you may not be able to use pennies at all once new fareboxes are installed throughout the system.

Is it possible to cheer that decision and cry for it at the same time?

SmarTrip will smooth the boarding-a-bus process tremendously. Pennies slow it down tremendously.

Many is the morning that I have stood -- or watched others stand -- in the rain while a fellow rider fumbles for change, drops coins on the floor, can't figure out how to deposit coins in such a small slot or all of the above.

With pennies, the fumble factor will always be with us. With SmarTrip, each of us will be up and aboard in less than three seconds.

Okay, truth time.

I've often been one of those fumblers myself.

Because I often pay all or part of my bus fare with pennies.

Metro may think it is a transit system, but I am here to tell you that it's a penny dump of last resort.

Where else can you slip 110 Abe Lincolns down the hatch and not raise anyone's eyebrows? Where else can you lighten the load on your pocket quite so quickly or so efficiently? How else can you clean out that drawer at home without burdening a church collection plate or an office coffee mess?

Pennies are so universally unloved, and so universally unvaluable, that a member of Congress has actually proposed that they be abandoned. But on Metro, pennies are tolerated, every day, every week.

Metro shoulders an enormous burden by accepting pennies. At Metro Counting Central -- in the basement of Metro headquarters -- pennies have to be hand-carried to counting machines and hand-carried from there to a bank, every single day. The sprains and strains that this causes, I can only imagine.

Then there's the burden on Metro's banks. Have you ever tried to deposit a fistful of change? The tellers will look at you as if you just murdered their pet bullfinch.

Now multiply that look by a couple of thousand, and you can imagine what Metro and its bankers face every single day.

I'm big friends with a fellow who has toiled inside the Metro bureaucracy since the day it was created (more than 30 years ago). He explained to me that the penny question, like everything else, is political.

"Who rides the bus? Poor people," said my guy. "For whom does the penny have the most meaning and the most value? Poor people."

That's why Metro has never before barred pennies, or even thought much about it, my guy said.

To bar pennies would have been to lay a haymaker on the chin of "a cleaning lady who's trying to get from Southeast to her job in Upper Northwest by Metrobus, and who's using pennies to do it."

"Can you imagine the hue and cry if Metro had demanded all these years that she put up $20 to prepay a SmarTrip card? This woman probably doesn't have $20."

Even if SmarTrip becomes available on every bus, my guy's cleaning lady probably will not use one, he predicts.

Reason One: It costs $5 to obtain a SmarTrip card, which might be "preemptively large dollars for someone who's on the edge," my pal thinks.

Reason Two: You have to trust a machine to deduct the correct amount every time you swipe the card over a reader.

"For a lot of people, especially if they're over 60, this isn't comfortable," my friend said. "They'd rather have $1.10 in coins in their hands, and pour it down the slot. They're the same people who won't pay for groceries at the Safeway by credit card because they just never have."

Reason Three: The card can get lost and would have to be replaced. "That's just one more hassle that a person who's already got a lot of hassles doesn't need," my friend said.

So if he and I had to guess, we'd say that pennies will never disappear from the Metro system.

Politics is all about squeaky wheels. If one passenger might be disenchanted or dispossessed by a no-penny rule, it'll never happen.

Metro hasn't tilted one way or the other yet. According to Steve Taubenkibel, a Metro spokesman, no final penny decision will be made until customer reaction to the no-pennies 90-day test has been analyzed.

Here's one vote for an end to pennies, regardless of how the SmarTrip test is received. Even the poorest of the poor can arrange to have nickels, dimes and quarters instead. A certain columnist can, too.