Eleven-thirty on a recent Saturday night. A woman from Arlington is driving north on Rock Creek Parkway, near the National Zoo, alone. In front of her is a slowpoke -- one of those glorious souls who has an open road ahead of him, yet insists on going 20 miles an hour.

The woman dawdles along for a mile or so, getting increasingly frustrated. She'd love to pass, but two-lane, winding Rock Creek Parkway is distinctly short of passing lanes at that point. Finally comes the turnoff for Arkansas Avenue. Milady chooses it, with a roar.

But who is suddenly filling up her rear-view mirror, and suddenly finding it no trouble at all to go 35? Yup. Same slowpoke. "I mean, he was right on my bumper," the woman later told me. "I didn't know what he wanted."

As the Arlington woman stopped at the first stop sign she saw, the former slowpoke slammed on the brakes, jumped out, ran up to her window and asked her in none-too-nice terms if she had a problem.

"No," the woman replied, "But I think you do."

A clever answer -- but the man didn't like it one bit. From behind his back he produced a billy club. He wound up and took a huge swing at the woman's door. Thump! He put a dent in the side of a $12,000 car.

But the man said no more and thumped no more. He climbed back into his car and squealed away.

The woman told me the story because she wondered what the man's true purpose was, and what she should have done. I wasn't sure, so I floated her tale past three savvy cops I know.

Independently, all three said the woman was lucky to have gotten off with a dented door. What the slowpoke may well have been after, said these three, was the woman herself.

"This is one of the oldest acts in the book that robbers and rapists use," one Park Police detective told me. "They go 20 miles an hour so they can get a good look inside the car behind them through the rear-view mirror. If there's a woman in there alone, that's exactly what they're looking for."

A D.C. police detective said some slowpokes will brake suddenly, in an effort to cause an accident and force the single female driver to stop and get out to inspect the damage. Once she does, this detective says, "it's not unknown for her to be robbed or dragged into the man's car."

The purpose of this story is not to make women who drive alone at night more fearful than they might be already. The purpose is to preach a little caution -- and to give a little practical advice.

As another detective put it, "Any woman who finds herself behind an unusually slow slowpoke at night should get out of there right away. I mean, right away. Turn around if you have to. But don't stay behind him. And whatever you do, don't beep the horn or flick your brights in his mirror." That may make him angry, the detective said -- and more likely to become violent.

To the shavers and dental flossers and makeup-appliers, we must now add . . . .a coloratura.

A Springfield correspondent calls to say that he was driving west on Old Keene Mill Road the other day when his eye happened to stray to the car beside his.

Behind the wheel was a woman. In her hands was a piece of sheet music. She was sightreading an aria as she puttered along at 40 miles an hour.

When I wrote recently about a high school student who had called to interview me for a journalism assignment, one of the first Posties to beat a path to my door was Kenny Greenberger.

As the news aide on our national desk, Kenny gets calls all the time from area students who have papers to write. They're looking for everything from Ronald Reagan's middle name (Give up? It's Wilson) to the latest on the balanced budget (Don't call Kenny on this one -- he says there'll never be a balanced budget).

Kenny and I agreed that it's always fun to talk to kids. But then he told me something that absolutely floored me. Of the calls he gets for student assignments, he said, about half are placed by parents.

"They call me and say their kids are doing an assignment for history class and could I give them the information?" Kenny said. "Sometimes their kids are 15, and here's the Mommy doing the calling. I mean, I'll help them anyway. But don't you think that's amazing?"

I do, indeed, Sir Kenneth. To "helpful" parents: If you recognize yourselves in this story, why not let your offspring do the calling next time? That'll be just as large a lesson as any info Kenny provides.

Shelby Friedman wonders if you've heard about the gourmet couple.

They had a fight, but then they decided to quiche and make up. say their kids are doing an assignment for history class and could I give them the information?" Kenny said. "Sometimes their kids are 15, and here's the Mommy doing the calling. I mean, I'll help them anyway. But don't you think that's amazing?"

I do, indeed, Sir Kenneth. To "helpful" parents: If you recognize yourselves in this story, why not let your offspring do the calling next time? That'll be just as large a lesson as any info Kenny provides.

Shelby Friedman wonders if you've heard about the gourmet couple.

They had a fight, but then they decided to quiche and make up.