The first time Edith B. Hebblethwaite rode a bicycle was in the second grade. She made it halfway down the block. It was fun, a kick, a thrill -- even if a friend had to help her stop.

More than 65 years later ("I'm the same generation as Ronald Reagan"), the senior secretary at the International Federation on Ageing is still making tracks.

"I don't feel compelled to do it or not do it," Hebblethwaite says. "But if it's a beautiful day, I can't resist."

On those irresistible mornings, she bikes from her home in South Arlington, through Arlington Cemetery, past the Kennedy Center, to her office on 20th Street. It's seven miles, although she adds modestly that "part of it is just coasting downhill." Going home, of course, it's exactly the opposite, but then she sometimes takes the Metro.

Hebblethwaite may have the advantage in longevity, but Jim Starrs started biking at an even younger age. As his mother put it: "He was born, and he leaped upon a bicycle."

"I do everything on them -- go to work, to court, around town, to church, shopping centers, libraries, museums, go to play," says the George Washington University professor of law and forensic sciences. "It's a living reflection of my own personality."

Until last year, the 55-year-old Starrs biked in every day from Springfield, a distance of 15 miles. Now he's down to three days a week, the result of a collision that caused a back injury.

It was the ninth time he'd been creamed by a car. "It's a clean way to go," he says, contemplating another accident. "You might as well do what you do best and enjoy most."

Welcome to the sometimes dangerous, always sweaty world of the bicycle commuter. Getting to the office on two wheels and your own power is something a varying number of people think they should be doing, depending on the price of gas, the span of their waists, and the presence of humidity or snowbanks. But only a small percentage actually have the fighting spirit to stick with it.

"We tend to be ungloved pugilists," says Starrs. "We're out there fighting a battle with motorists, with insults, with imminent injury, and with the city fathers and mothers, who refuse to put bike lanes and signs in. Bicycling demands dedication, a firmness of spirit -- and also a few muscles."

The 1980 Census offered this breakdown on how 1.5 million employes in the greater Washington area got to work: 833,000 drove alone, 356,000 rode in a carpool, 235,000 took public transit and 77,000 hoofed it.

Only 5,348 people said they biked to their job. Not exactly an overwhelming figure; more people (5,865) grabbed taxis.

While agreeing "it takes a lot of incentive to make people become bicycle commuters," Linda Keenan of the Washington Area Bicyclist Association points out that the Census was done on April 1, with workers being asked about their mode of transportation the previous week -- not exactly prime cycling time.

As a show of strength, the advocacy group is organizing Bike to Work Day next Thursday, which is also the start of American Bike Month. Convoys of commuters will bicycle in from selected points around the area, culminating in an 8 a.m. rally at Western Plaza, on Pennsylvania Avenue between 13th and 14th streets.

"Not only should it encourage people who are already bicycling to work, but it's a way of making them visible to others," says Keenan. "We also want to encourage the potential bicycle commuters who may not venture out by themselves but will do so in a group. Next time, maybe they'll go alone."

Meanwhile, efforts are under way to provide an updated and more comprehensive estimate of the number of purposeful or utilitarian bikers, as the commuters are called. The biannual cordon count of traffic entering the city, which will end in two weeks, is putting special emphasis this year on counting bicycles.

"Our feeling is that a lot more than 5,000 people are commuting by bike during the warmer months," says Tom Pendleton, bicycle coordinator for the D.C. Department of Public Works. "If we see a trend toward heavier bicycle usage than has been expected, it will lend support for heavier emphasis on bicycling as part of the city's transportation mix."

That mix has been lumpy recently, Keenan says.

"Programs for bicycling in the D.C. area have really fallen down in the last few years," she says. "The incentives necessary to create a bike boom -- dedicating space for bikers on the road, secure biking facilities, showers in workplaces -- haven't been there. Potential commuters won't join current commuters unless there are more facilities."

The problem, Pendleton says, is biking's increasing acceptance, which makes it "certainly not one of the first things that's looked at" in terms of new funding.

"People don't think of it as a cause they have to go out and fight for," he says, noting that in the District itself, only two new bike routes have been added since 1978: a shared roadway with a short stretch of bike lane between Dupont Circle and Cleveland Park, and a separated path on South Dakota Avenue. During the same period, several streets have lost their bike route signs.

As the District goes, so goes the nation.

"There are fewer bike route signs around the country than there were five years ago," says Katie Moran of the Bicycle Federation, a national organization promoting cycling.

"Communities are leery about liability -- some of the signs went up almost at random, and what happens if someone has an accident? Cities are doing things to improve biking -- like widening a curb lane -- but not pointing fingers at it."

A further problem, in the District and other big cities, is caused by bicycle messengers.

"One hundred and one percent of us hate those bicycle messengers, because they give us the worst reputation," says Starrs.

"Their on-the-road demeanor is not that good, and when people are confronted with them, they say, 'Get those damn bicycles off the road!' " says Chris Grimm of Bicycles USA, another national organization. "You can't really blame them."

This, combined with the continuing American love affair with the car, means cyclists do not usually get the courtesy they do in other countries. "A bicycle here is looked at as a toy, whereas in any other country in the world it's considered a vehicle," says Grimm wistfully.

It wasn't always that way. Not only did bicycles originally rule the American roads, but during the first cycling fad, in the 1890s, they were the reason many of the roads were built. With the arrival of the interurban railway and the automobile, however, the craze collapsed.

For the next 75 years, the bike was relegated to children, and it's been an uphill climb back to the adult world. But as the nation's physical infrastructure starts to crumble, an opportunity is being provided.

"As the highway system undergoes rehabilitation and reconstruction, bicycle provisions can and are being added," says Pendleton, adding that on Key, Chain and the George Mason Memorial bridges the bike sidewalk either has been or is being widened and resurfaced. "You can do more for biking with a gallon of paint than with a whole engineering textbook."

However, Starrs -- an individualist among individualists -- says more facilities aren't needed.

"Bicycles and commuting are incompatible except for the lunatic fringe, of which I'm one," he says. "It's not as simple as just talking about the problems of traffic. There's the weather, employers who are resolute against the bikers bringing their bikes in, and the whole mentality of our society that every time you perspire, you have to take a shower."

Even if the facilities were there, would they be used?

A partial answer may be found in the increasing traffic density on the Beltway and in the northern Virginia suburbs, a condition that is shortening tempers and lengthening what should be brief trips.

"Bicycles are by their very nature high-occupancy vehicles," Pendleton says. "Large quantities of bicycle parking and good routes leading into the suburban Metro stations could have a significant impact on traffic."

And in bad weather? "Wisconsin has terrible winters, but has more bike use per capita than most other states."

The Bicycle Federation estimates there are 1.8 million bicycle commuters in the country. Enthusiasts point to several cities -- including Madison, Wis.; Eugene, Ore.; Gainesville, Fla. -- as being particular meccas for self-powered two-wheelers. Palo Alto, a 56,000-population city in California, has probably gone the furthest to promote cycling. Among the measures passed by its city council:

A 3-year-old ordinance requiring any new commercial or industrial building of at least 10,000 square feet to provide a shower for employes.

An 8-year-old ordinance requiring parking facilities at a ratio of 10 percent of auto parking. A rack alone is insufficient; either lockers or a locked room must be provided.

Approval of a bicycle boulevard -- two miles of car-free roadway. It's expected to be the beginning of a network.

"It's helped create a more people-oriented community versus one geared only to automobiles, like Los Angeles," says city council member Ellen Fletcher, a guiding force behind the measures. "These people would be in cars creating more traffic if they weren't riding bicycles."

The optimum that most bicyclers wish for is not to replace automobiles, but simply to coexist with them. And this, they say, is slowly beginning to happen.

"We're seeing increasingly that bicycling is being integrated into the regular responsibilities of local agencies," says the Bicycle Federation's Moran. "You won't necessarily see special routes, but there'll be general improvements to the street system -- wider curb lanes, more sweeping of the curb area."

Such improvements might catch a bigger crowd, but the really dedicated will be out pedaling anyway, mindful of both the risks and the rewards.

"A bicyclist is always on center stage. It takes a theatrical approach to life," says Jim Starrs. "But we tend to feel things -- the wind, the road -- more sharply. I can see the coming of spring before the buds."

Or as Edith B. Hebblethwaite puts it:

"When I've ridden to work, I feel good the whole day."