This is what it's come to outside the National Child Research Center on Highland Place NW in Cleveland Park, one of the best nursery schools in Washington, on one of the best streets.

At 11:30 a.m., a dozen sport utility vehicles idle in a line half a block away, behind a white mark painted on the asphalt. Each car has a number on the dashboard.

The school's speech therapist and development director double as traffic cops, wearing orange vests and jabbering into walkie-talkies.

"I have 96, 83, 85," says the speech therapist, standing with the queuing cars.

"Bring me three more," says the development director, posted in front of the school.

Cars 96, 83 and 85 glide up to the school and wait. The parents are forbidden from exiting their vehicles. Repeated violations of this rule can mean expulsion of Junior from the nursery program and therefore, some believe, relegation to an uncertain future of public education.

Here come kids 96, 83 and 85, tottering down from the school's immense wraparound porch with the dreamy, trusting forward inertia of preschoolers. Each holds the hand of a teacher, who buckles the child into the parent's car seat, and off go the SUVs. More vehicles are summoned, more join the queue, until morning pickup is complete in less than half an hour.

This ritual is carried out with the precision of air traffic control at Dulles, and the tension of waiting for service from Seinfeld's Soup Nazi.

But it's a modern ritual, something new in this out-of-the-way nursery school that many construe as the first step to Harvard -- and others remember as the unassuming neighborhood sanctuary that just happened to attract presidential offspring.

The grown-ups know they are being watched by other grown-ups: expensive lawyers, traffic consultants, city officials, architectural historians and especially neighbors -- neighbors behind windows and on porches with cameras and notepads, gathering evidence, occasionally calling police.

During pickup they convene on the porch of the yellow house next door. They watch as a parent in an SUV squeezes into a parking place and bumps into a resident's Porsche. Twice.

Nursery traffic control is not always precise: Some cars ignore the instructions of the ladies in orange vests, make U-turns, briefly block streets.

"There is no letup," says Laine Kaufman, who lives across the street. The staggered pickups and drop-offs mean traffic peaks several times a day, albeit for short periods. The school has 108 children present at any one time and a total enrollment of 171.

"There goes another car through the stop sign without stopping," says Sallie Beckner, who adds that she has a year's worth of videotape showing such infractions.

The school wants permission to double its facilities and add 10 children to maintain its excellence. Many neighbors say no, many say yes. It's another Cleveland Park civil war -- two stacks of petitions, untold money, untold hours, Web-posting vitriol, packed hearings, passive-aggressive speeches by residents who sound like professional litigators because they are professional litigators -- but it's not a simple NIMBY story.

Happily oblivious are the bundled figures capering to and fro -- only now their SUV getaways will be featured in dueling photographic exhibits marshaled to prove opposite points today at a hearing before the Board of Zoning Adjustment, which will eventually rule on the expansion plan.

For this the parents are paying nine months' nursery school tuition of as much as $12,000.

From Harmony to Discord NCRC and Cleveland Park grew up together, and until recently got along famously.

The 75-year-old school moved from Adams Morgan to Highland Place in 1930. The Center helped pioneer the pre-World War II rise of the nursery school movement.

Long gone are the days when it was an actual research center, when researchers hid in the bushes and took notes on play habits, when they recorded the children's daily intake of food, potty production and sleep quality. They published papers such as "Certain Factors Influencing the Duration and Character of the Afternoon Sleep" and "The Learning of Abstract Concepts of Size."

In the 1970s, the school was a pilot center for "cued speech," a method to help deaf children communicate. Since then, research has dwindled to the occasional collaboration with a university as the school focused on simply being a top nursery school.

NCRC has always preached a general approach that includes the idea that young children can do more for themselves than they are allowed -- getting dressed, serving food -- and the idea that children learn through play.

Also from the beginning it attracted "the sons and daughters of senators, women wage earners, writers, artists and an average cross-section of the infant population of the city," as The Post wrote in 1930.

Four-year-old Buzzie Dall, Franklin Roosevelt's grandson, was driven there every morning from the White House, and Lyndon Johnson's daughter Lynda Bird also attended. The school enrolled children of lawmakers including senators William Proxmire and H. John Heinz III and congressman Morris Udall. Gerald Ford's press secretary Ron Nessen and Bill Clinton's press secretary Joe Lockhart sent children. Alexa Halaby, sister of Jordan's Queen Noor, is a board member and leading advocate of the expansion who has two daughters who graduated and a son still there.

One letter to the city in support of the expansion came on ambassadorial letterhead, dispatched by Stuart Bernstein, ambassador to Denmark and an NCRC grandfather.

Critics say NCRC is a "nursery school on steroids" and call it Washington's version of New York's 92nd Street Y Nursery School, the kiddie asylum for which neurotic parents supposedly begin plotting admission strategies before their child's conception.

But in its worn circa-1905 mansion, NCRC seems lower-key, more like home than the stereotypical gold-plated nursery. Just a generation ago a goat lived on the property as a farm pet, and a trashed Volvo was parked on the grounds as play equipment. The school preserves that air of casually calculated play experience. And it draws from far beyond rich, white Cleveland Park, seeking minority students (35 percent), scholarship students (15 percent) and children with disabilities (two kids per classroom).

Still, you don't just write a check and send your kid. Parents must come in for a group meeting with school staff, and children must participate in a trial "play session." Last year, 313 applied and 50 made the cut. Four out of five graduates go on to private schools, such as Maret, Beauvoir, Sheridan, Sidwell Friends and Georgetown Day.

"It's like anything else in life: You start with what's excellent and you move on to what's excellent," says Kaufman, the neighbor across the street. "It's not that this is exclusive because a certain type of people go there. It's because the caliber of the staff is so high and the caliber of the curriculum is so high."

She's referring to the teachers, who are likely to have master's degrees, and the published curriculum, which runs to 288 pages with chapters titled "Cognition: To Sense Is to Invent" and "Motor: Moving and Knowing."

What a rave from this opponent of the expansion. In fact, Kaufman's two children attended NCRC.

That's one reason why this battle is unusual. A number of the opponents sent their children to the school, and some are even former board members. They complain that the school's vision has changed from a homespun, if elite, nursery school to something bigger, grander.

"It's sad for me to be in a fight with my children's teachers," Kaufman says. "I love those teachers."

School supporters see this as hypocrisy.

"I'm enraged with parents who sent their own children there and don't want to see it grow with the times," says Georgia Irvin, an education consultant who counsels parents on how to get their children into good schools. She sent her two children to NCRC and now has a grandchild there.

'Kansas on the Potomac' Named for Grover Cleveland, who had an estate here, Cleveland Park started becoming fashionable around the time of the Kennedy administration.

Relatively young, sometimes prominent, intellectual, frequently liberal, civic-minded couples began moving in.

James and Libby Rowe -- he was an adviser to Presidents Kennedy and Johnson, she was appointed by Kennedy to head the National Capital Planning Commission -- lived next to NCRC. Nearby were Nicholas deB. Katzenbach, Johnson's attorney general, and George Reedy, Johnson's spokesman.

A longtime resident tells an anecdote that bespeaks the idealism of that time: He wanted to buy a house in the neighborhood but was informed by the owner, a prominent liberal, that the house was being reserved for a black family. Understanding completely, the would-be buyer rented until a black family moved in.

It's no longer a neighborhood most young families can afford. Houses routinely sell for more than $1 million. It's the kind of neighborhood where workers need three ladders to reach the chimney to fix the flashing. The 100-year-old architecture makes new suburban manses look Potemkiny. There's a profusion of dentils and dormers and friezes and porches. Back yards plunge into ravines with 30-foot rope swings hanging from ancient oaks.

One neighbor has a big blue-and-white inflated bubble in his yard that looks like a small college field house. What the heck is that? Oh, a shelter for his swimming pool.

It gives the impression of a sleepy village, with no sense that Connecticut Avenue and the Cleveland Park Metro station are only blocks away.

"I call it Kansas on the Potomac," says Ana Evans, a resident with a view across the city to Brookland from her front porch on Ashley Terrace.

Anne Large would agree with Evans about that, if not about the school. Evans opposes the expansion, while Large, who lives a few blocks away, attended NCRC, then Beauvoir and National Cathedral School, all nearby.

"I walked to school all the way through high school," Large says. "Cleveland Park was a great small-town feel in a big city."

After she married and started a career, she moved back, in part so her children could have the same experience. One son graduated from NCRC and now is at Beauvoir, the other is at NCRC now -- and Large is a leader of residents supporting the expansion.

Jon Thoren, another leader of the neighbors backing the school, went to the morning drop-off at 8:30 with his digital camera to witness the congestion. He has twin daughters in the school.

Thoren said the queue never had more than three cars, and quickly dispersed. "Any objective person would conclude that the amount of traffic generated by the school was reasonable," he contended.

The neighborhood is also home to Peter and Marian Wright Edelman; Derry and Greg Craig, who defended Clinton during the impeachment; writers Judith and Milton Viorst; journalist Seymour Hersh; Washington Post Chairman Don Graham; retired diplomat Max Kampelman; Washington artist Lou Stovall, Commission of Fine Arts Secretary Charles Atherton; and Tersh Boasberg, chairman of the city's Historic Preservation Review Board, which approved the school's proposed design.

At the preservation hearing late last month, Boasberg looked at the crowd of more than 80 and quipped, "I'm glad to see all my neighbors here." It was the largest audience for a preservation hearing in recent memory. The partisans hadn't waited for the official proceeding, they just dropped their petitions on Boasberg's front porch.

Some of the prominent names have taken sides. Greg Craig, who lives two doors from the school, helped organize the opponents. Judith Viorst and Peter Edelman signed petitions against the expansion.

The fight that began almost a year ago has turned neighbor against neighbor.

Most residents on the streets immediately around the school oppose the expansion. Opponents say they are more than 100 families strong. Yet nearly 120 families not as close to the school support the expansion, according to those partisans.

Families from both camps participate in the local soccer league, or the local basketball league, or the Cleveland Park Club.

"We no longer have the warmth we once had," Kaufman says. "It's sad."

Too Much Foot for the Shoe Susan Piggott, NCRC's director, wrestles with questions that boil down to: What do children need, and what do they deserve, if one has the wherewithal?

The well-worn mansion is bursting at the seams since 27 students were added in 1990, in part a response to findings that children should begin nursery school as early as 2 1/2, and separate studies encouraging the inclusion of disabled children.

The building is essentially six classrooms linked by stairs. The doors have one-way mirrors so parents can watch their children without being seen.

Upstairs, about 20 3 1/2-year-olds are busy with hats and coats and posters as a teacher repeats in a singsong voice meant to be remembered: Pick your name card, switch your cubby over.

There are two teachers, a teaching assistant and a parent, an excellent adult-student ratio that the school wishes to increase by adding two classrooms. These morning students must make way for an afternoon class. They are lining up to go down for traffic control.

A class of 3-year-olds is eating rice muffins prepared by a mother for the Chinese New Year. You don't notice the little girl in the corner is visually impaired until you see the little boy helping her.

In another room the speech therapist and the occupational therapist (who helps young children with fine-motor skills necessary for writing) are sending kids on an obstacle course of mats and tunnels and asking them questions about their favorite things, an exercise linking motion with brain work.

A separate building called the Playhouse has a space the size of a large Cleveland Park living room that serves as the library, music room and motor skills room. Piggott says the latest research shows that carefully designed movement activity "is important not just for physical development but also for brain development for later learning, reading, writing and math."

The current motor skills room is too small for children to get up momentum while running and jumping. NCRC wants a bigger one.

All told, the $3.5 million expansion would put a large addition at the rear of the mansion, including an elevator so children in wheelchairs can attend, and a new building the size of a house with the motor skills room, classrooms and meeting space. The one-acre lot would remain 80 percent open.

"We consider these basic, vital needs," Piggott says.

A Matter of Trust Neighbors began to sour on NCRC in 1994 when, without warning and lacking permits, the school knocked down mature oaks and started bulldozing a new playground. The residents got a stop-work order.

At a zoning hearing in 1998, a school director before Piggott testified there were no plans for new construction and no plans to increase enrollment beyond 120.

A year ago the school proposed the addition and an increase in enrollment -- which already stood at 171. It promised to cap enrollment at 181.

Neighbors in the immediate vicinity went bonkers. They no longer believed the school was being truthful.

"Everything NCRC does, the way they operate with the students and the families, is with the highest integrity," Kaufman says. "The way they have dealt with the neighborhood is not that same integrity."

The school says it's never been a secret that total enrollment has been higher than 120 since the 1980s. The reason the school used 120 at the hearing was because school officials were referring to total students at one time, not total enrollment, according to the school. City inspectors already knew total enrollment was greater.

But Steve Hunsicker, who lives across from the school, says, "The most charitable thing you could say is that the school hid or obscured that they had far more than 120 students."

Fifty families living near the school contributed money to hire their own zoning lawyer, a traffic consultant and an architectural historian. They won't say how much they spent. "I would tell you there's a wide range of ability in the neighborhood, and people have dug deep to give what they can," says Bill Taylor, who helped organize the opposition.

The neighbors say the new construction is massive and institutional, despite the preservation board's architectural approval. And they are raising traffic issues that they say have been festering for years.

Narrow, curving, two-way Highland Place can fit only three SUVs abreast. During pickup times, westbound cars have to venture into the eastbound lane to get past the school. The Department of Transportation just issued a memo to the zoning board, calling the car queue "dangerous."

After 73 years, the opponents say, NCRC is attempting to get too big for Cleveland Park. "It's like my kids in first grade playing Cinderella," Kaufman says. "It's like trying to fit a size 10 foot into a size 6 shoe."

Many opponents say they'd accept a compromise with enrollment staying the same and minor modifications to the buildings. But their legal brief asks the city to remove 51 students.

Changing and Blaming A lot of people in Cleveland Park are asking the same question: What changed?

What changed, ask neighbors against the expansion. For 73 years NCRC lived happily within the same building space. Enrollment has not been increased since 1990. The school maintains its excellent reputation. Why are its facilities suddenly inadequate?

What changed, ask the school and its supporters. Enrollment has not increased since 1990, so traffic must have been roughly the same for 13 years, and it's never been much of a public issue.

Blame the cost of staying on the cutting edge, the new wisdom of child development research.

Blame the cursed rise of the sport-utility vehicle, and the new wisdom of putting each child in a car seat -- which means you can't carpool five kids at once as in the old days.

Maybe blame smart people talking past each other, or not finding the right things to say.

Cleveland Park knows how to fight over new uses of its precious acreage, and has done so many times before.

But every once in a while, Cleveland Park also knows how to put its considerable talents and bankrolls together in a united crusade. A few years ago, some neighbors pitched in on a big project. They raised $300,000, mostly from Cleveland Park residents. And they did the work themselves.

The result, on Macomb Street, was a brand spanking new playground for children.

Susan Piggott, the research center's director, does yoga-like "belly breathing" exercises with Collett Preston, left, Ana Sosa-Ebert and Alexandra Alfonso.Neighbors Ana Evans, Susan Taylor and Danny Ince, who oppose the expansion of the National Child Research Center, watch the parade of vehicles on Highland Place NW. The school's expansion plan gets a zoning hearing today.Preschool personnel walk children from their parents' cars, above, in an effort to keep traffic flowing on narrow Highland Place. Jon Thoren, right, who has twin daughters in NCRC, is helping lead the fight for expansion.Liam Woo works on his motor skills with help from Katherine Joncas in a space that also serves as a library and music room. The expansion would create a separate motor skills room, a "basic, vital" need, says director Susan Piggott.