Progress marches on, but it's marching kind of disruptively these days down at 20th and K streets NW. They're building a new office building there, which is always an exercise in acute traffic clog. But, as Michael J. Carter writes, this project has taken the usual clog and added more.

"Every morning during rush hour , the workers on the site see fit to block the two left lanes of 20th Street between I and K Streets," Michael writes. " . . . . Why can't these lanes be blocked after the morning rush is over?"

I suspected I knew the answer, but it was worth a walk over to 20th and K to play Inquiring Reporter. Here's what I got, as expected, from a foreman who didn't want to give his name:

"For a lot of this job, the lanes have to be blocked all day long. Nobody's picking on morning commuters. We're just trying to keep the job within the estimated costs. If we had to keep all the traffic lanes clear for both rush hours, we'd be here 14 hours a day, and we'd be paying overtime for nearly half of that. There's no way that's going to happen."

Ray of Hope Dept.: The job is expected to be finished by next spring, and traffic may be flowing freely past 20th and K well before that.

Speaking of 20th and K, here's a marvelous memory from Bob McMillen, once almost of that corner, now of Lovettsville, Va.:

"When I arrived in Washington late in 1939, I read the classifieds in the Star and followed through on one ad.

"I inspected the room (no kitchen) on the second floor front of a stone house on the north side of K Street, either in the 2000 or 2100 block. There was mahogany furniture, a fireplace with wood and maid service.

"I turned it down for two reasons. One, it was too expensive ($50 a month). Two, it was too far out of town."

A hearty welcome to the latest members of The Super Stoppers Club, that ever-growing army of former smokers who will now reap the second biggest benefit of quitting: a mention right here in the funny papers.

"Mystery Lady" of Fairfax is a CB radio amigo of "Falcon" of Manassas. The bird man kicked the habit on Dec. 7, 1984. "Hoooooooooray!" writes M.L. That's a big 10-4, good buddy.

And here's a "Yeaaaaaa!" from Michelle, girlfriend of Tom Zakielarz of Takoma Park. Tom has been clean since early 1984, says Meesh. Well done!

Joe Switkes of Chevy Chase went cold turkey on Oct. 31, 1983. Jim Tam went the same way 18 days sooner. Ann Bobys has been without a cig since December 1982, reports her sister, Dorothy M. Epstein of Chevy Chase. And David Braziel of Clinton wins the No-Nicotine Romance Award. He quit on Dec. 1, 1984, on his wife Brenda's birthday (and in her honor).

Barbara Stein of Columbia quit seven years ago, so she knows what it takes. She also knows how to say congrats -- to fellow quitters Gregg Stein (her son), friend Rosemary Palmer and coworker Cathy Stefano.

Courtney Boccucci quit last January. Ditto Brian McHugh of Falls Church, and a couple from Arlington: Linda and Ken Smith-Christmas.

Here's the sort of family affair I can go for. After 40 years of puffistry, Warren E. Tuthill Sr. of Fairfax quit smoking. Within the next few months, so did two sons and four daughters. Wife Joan had quit four years earlier.

Bethesda quitter: Elizabeth Kernan. Kensington quitter: Ruth Anne Willhite. Columbia quitter: Dawn Griffin. Forestville quitter: Lorna Anstice (who had smoked for a mere 49 years).

Way to go, you four habit-kickers from The Hospital For Sick Children. You're Director of Nursing Service Joan Reed, Director of Engineering John Quinn, Fabric Care Assistant Vivian Barnard and Registered Nurse Sylvia Dixon.

Long-time smokers who saw the light: 1) Sally Carruthers, a 50-year puffer who quit in June, 1984, according to her daughter, Mrs. Edward Prince of Chevy Chase. 2) Charlet Levesque of Kensington, who smoked for 47 years. 3) Lucy A. Andes. Her sister, Shirley M. Peters of Forest Heights, says Lucy quit after 41 years when jumping rope with her grandchildren made her winded!

Bruce Jones of College Park has been smoke-free for four years. Steve Knick stopped last April Fool's Day (and he wasn't kidding). Dave Nelson of Charlottesville vowed to quit the day before Thanksgiving "so I'd have something to be thankful for." He did, and he is. And Howard Schlesinger of Arlington has gone without for six years, says his proud wife, Betty.

Congrats to all Super Stoppers. It's not easy. But it is worth it. If you still smoke, and would like to see your name right here, you know what you have to do . . . .