Ten years ago William H. Whyte created a research organization called the Street Life Project whose purpose was to document what people actually do in urban spaces, rather than go along with accepted assumptions about the ways people behave.

Using counters, maps, charts and, most important, a battery of hidden Super-8 time-lapse cameras, Whyte and his colleagues set about recording the dawn-to-dusk meanderings of people in some of New York City's more populous streets, playgrounds and plazas, and also in some of the city's less popular places.

The challenge was to find out why people liked certain places and used them fully, and why they avoided other, similar places. The question put was, if significant correlations could be established between, say, the availability of sunlight and heavy usage, then could not the quality of urban open spaces be effectively written into law?

The answer was yes. The project's preliminary findings prompted important changes in the city's open-space zoning provisions. As Whyte avers with admittedly "parochial pride," a direct consequence is that "whatever else it may be, New York is now the most sittable city in the country."

Despite its obvious New York bias -- a tilt in favor of high-density cities -- Whyte's study merits careful attention in Washington and elsewhere. To spread the word, he produced a 55-minute film, "City Spaces: Human Places," that will be aired tomorrow at 8 p.m. as part of the Nova series (WETA-26) and repeated on Wednesday at 2 p.m. and Thursday at 10 p.m.

The film is entertaining and informative and can be recommended without hesitation to anyone interested in the healthy street life of cities. It should, however, be required viewing for all architects, developers, bankers, politicians and planners currently engaged in rebuilding downtown Washington and area suburban centers. After they see the film, they should buy Whyte's companion manual, "The Social Life of Small Urban Spaces" (published in 1980 by The Conservation Foundation), the better to ponder his lessons.

Whyte is an urbanologist who ironically is most widely known for his study of 1950s suburban corporate executives, "The Organization Man." He obviously loves cities and recognizes that the essential object of this affection is the busy city street. It is not at all surprising that among the more fetching moments in his film is a sequence on the "choreography of the plaza" wherein dozens of individuals put together a beguiling and complicated, if unplanned, "dance" in front of the researchers' omnipresent candid cameras.

The conclusions reached by the Street Life Project are not startling. The chief attraction and chief activity in the best city spaces, we learn, is "people looking at people." There is very little danger of overcrowding or overuse even in the most popular place: The films proved that strangers and friends alike tend to cluster where there are other strangers and friends. As Whyte observes, "It is people who determine the level of crowding, and they do it very well . . . Underuse, not overuse, is the major problem."

Not surprisingly, the researchers found that it takes a combination of things to make a successful urban space -- availability of sun, protection from wind, openness to the street, accessible fountains or pools, a correct proportion of trees planted in the right places, and a variety of uses, the more important of which is serving food either from vending carts, kiosks or built-in cafes.

The crucial single factor, however, proved to be sitting space. Admitting that this discovery hardly is an "intellectual bombshell," Whyte tells us that "people tend to sit most where there are places to sit . . . The most attractive fountains, the most striking designs, cannot induce people to come and sit where there are no places to sit."

If these findings seem to make common sense, they go against the grain of established practice in the building and rebuilding of our cities, which all too often ignores the items on this list one by one. One key value of the Whyte study is that its conclusions were based upon voluminous direct observations and therefore cannot be dismissed easily as lightheaded, utopian and impractical. By stating its case with the authority of empirical science, the study contributes greatly to an emerging, positive consensus concerning the relationships between people and urban design.

Still, Washington is a very different city from New York, spread out and low in density by comparison, and subject to its own unique tradition of urban planning. Indeed, if you think only of the monumental core -- a reverse model for the famous Jane Jacobs dictum: "A city cannot be a work of art" -- you might conclude that the study simply doesn't apply. This would be a mistake.

Here is not the place to bring up all the old arguments about the rigidity of the Mall except to say that even if it is vastly (and obviously) different from the kinds of urban spaces Whyte talks about, people seem to like it and to adapt to it beautifully. But even the Mall unquestionably could be improved by strategic clusters of activity under the elm trees, and the same goes at least double for the new sidewalks along Pennsylvania Avenue, where those beautiful new double-sided benches are being laid out as if in a military parade.

Whyte's study applies much more forcefully to the rest of the city. Of course, thanks largely to Charles Pierre L'Enfant, Washington has a plentiful stock of beautiful, well-used center city parks, but the freewheeling way that western K Street, Rosslyn and Crystal City was allowed to develop, does not inspire confidence in the future of the rest of the city, or region. The business community of late has shown signs of enlightened interest in these matters and the city government has at least spoken sweetly on the subject, but there is a long, long way to go.

Whyte's study can be of immense help in this, in principle and in detail. There are many possibilities. One major suggestion is that developers, architects and planners alike look again at the distressing fad for enclosed retail spaces in the middle of new megablocks. The problem of architectural redundancy is obvious; Whyte demonstrates, also, that such spaces tend to be much less welcoming, less hospitable and less entertaining than the streets themselves.

There are five really huge interior courtyards about to be built in the new old downtown west of 15th Street, maybe more. Enough already! Any more and our downtown sidewalks will be like Houston's -- empty. Prudence as well as Whyte-style common sense suggest that we turn our money and creative energy outward, toward the streets, while experience suggests that we sorely lack the imagination and the skill.

It gets down to things as basic as how to make a place to sit that is physically and socially comfortable. We just don't do it very well. One of the few small urban spaces in Washington that can claim something of a lively social life, in Whyte's terms, is the northwest corner of Connecticut and L streets NW. The office building there (designed by Chloethiel Woodard Smith) politely angles away from the corner, and on most days there are flower and food vendors and even an acceptable place to sit around a raised circular pool of water. So far, so good, but the rest is a study of missed opportunities: planters that are too crowded and too narrow and too high to sit upon -- wasted energy.

A small thing, perhaps, but important, and far too indicative of performance in the capital city. Clearly, we need to do more and do better with the streets and the spaces and buildings that face them. A good place to start would be to take to heart some of the lessons of "City Spaces/Human Places."

True, the best and the worst of the urban places analyzed by the Street Life Project owe their existence to zoning incentives that allowed outlandish building heights in exchange. Because of the height limitation, Washington developers will say it can't happen here. The city's best answer to that is: It can be done and will be.