Easy circles: Westmoreland Circle (at Massachusetts and Western), a fairly nonthreatening circle at the D.C./Maryland border (though it has its share of accident reports), or Sheridan Circle, on Massachusetts Avenue above Dupont Circle -- a pretty circle surrounded by embassies and fed by quiet little side streets.

The circles most likely to cause you trouble:

Ward Circle, where Nebraska intersects with Massachusetts, at American University. Keep your eyes open here; this is one of the most complicated, least user-friendly circles in town -- really an oval (Nebraska) within a circle (Massachusetts). Be prepared for traffic lights on both Nebraska and Massachusetts, even in the middle of the circle.

As D.C. driving trainer Ted Silverman explains, "Normally a car entering a circle is supposed to stay in the same lane it was in, but here, if you're in the left lane going north or south on Massachusetts, and you want to continue on Massachusetts, you have to move at least one lane to the right."

Observes Arlington therapist Bayla Kraft, "Listen to the honking here. People at this circle are always in a rush and often seem hostile." A circle for strivers, not daydreamers.

Dupont Circle, where Connecticut meets Massachusetts (one of the few circles where you'll see human traffic). It pays to study this 10-spoke wagon wheel, which is essentially two concentric circles, into either one of which you may easily find yourself locked by the dividing median, or raised strip. To get onto, or stay on, Massachusetts, aim for the inner track; to get onto Connecticut, New Hampshire, or 19th, shoot for the outer track and try to have a clear idea where you want to exit or you may have to go around the circle more than once.

Several streams of traffic enter the outer circle at the same time, so if you are stopped, say, at the light at Riggs National Bank on Connecticut you have to floorboard it to get into the circle before the cars entering from 19th or New Hampshire charge in. The streams of traffic entering from the north are particularly aggressive. Crossing this circle on foot is no picnic, either.

"Psychologically, Dupont Circle is interesting," says Kraft, "because you have so many choices, but there's no time to be indecisive, and if you make a wrong choice it's too late."

* Thomas Circle. Massachusetts traffic can tunnel under this medianed oval within a circle. The inside oval carries 14th Street traffic straight ahead, with no turns; the outer circle offers choices: Vermont, 14th, or Massachusetts.

Union Station. As you travel south on Massachusetts from Thomas Circle, zig-zagging around Mount Vernon Square, you will arrive at the semicircle facing Union Station, an odd circle that has been engineered into a semi-cul-de-sac. Remain alert to street signs here or you may end up at Union Station and have to go around again.

Washington Circle. Not a circle for the timid, particularly during evening rush hour when K Streeters going home jam Pennsylvania Avenue and tend to assume the right of way. The trick here is to get onto K Street going east from 23rd Street, or onto 23rd Street from Pennsylvania Avenue.

Logan Circle. Eight streets feed this wide circle, and though there's not much traffic, inexperienced drivers have problems because of unclear lane markings and the poor arrangement of traffic lights, says driving instructor Silverman.

Chevy Chase Circle. Surrounded by churches, this apparently simple circle, which separates the District from suburbia, is a problem at rush hour, when traffic on Connecticut yields very reluctantly to traffic in the circle. A few years ago Washington drivers mounted a campaign to get rid of the trees in this circle, because motorists kept hitting them. The trees won, though one in particular looks a little the worse for wear.

At rush hour, the trick is to get into the center of a circle (to pass the "spoke's" effluence) and then back out again, to exit. Nowhere does driving require such a grasp of hydraulic engineering.