A cyclist rides on a sidewalk near 17th and L streets NW in the District. It’s against the law to ride a bike on the sidewalk in downtown Washington. (John Kelly/The Washington Post)

What do you say to someone riding a bike on the sidewalk in downtown Washington? What you want to say — if you’re me, anyway — is “Get off the sidewalk, you dummy!” But that can sound aggressive. It puts you in an unfavorable light, allowing the cyclist to feel aggrieved.

So what I did the other day when a guy on a bike wheeled past me on the sidewalk before stopping at a light at 15th and I streets NW was simply ask a question. “Excuse me,” I said. “I’m just curious: Why are you riding on the sidewalk when there’s a bike lane right there?”

Now, he could have been blowing smoke, but he politely answered, “Yeah, I’m sorry. I didn’t see the bike lane there. I’m going to get on it now.”

And then, when the light turned green, he did.

A week later, I had the opportunity to interact with another cyclist. Well, when I say I had the opportunity, I mean I took the opportunity. I have the opportunity nearly every day, because so many cyclists either don’t know or don’t care that they’re not allowed on sidewalks downtown. (By “downtown,” the District Department of Transportation means the area bounded by Massachusetts Avenue on the north and D streets SW and SE on the south and from 23rd Street NW to Second Street SE.)

This guy was going down the L Street NW sidewalk at a pretty good clip. I couldn’t engage him in conversation so I shouted, “There’s a bike lane, buddy!”

I think he could tell that, although I said “buddy,” I was thinking of another word entirely, for he waved his entire hand in a way that suggested he wanted to wave just one finger, and I don’t mean his pinkie.

I know there’s lots of rancor these days over how cyclists, motorists and pedestrians interact. Cars threaten bikes. Cyclists blow through red lights and stop signs, threatening pedestrians. I wish Washington had the sort of cycling infrastructure you find in many European cities. We don’t. But could bikes at least stay off the sidewalks downtown?

Maybe pedestrians could politely mention to cyclists that they shouldn’t ride on the sidewalk. But that’s not without its dangers. A while back My Lovely Wife did that on 20th Street NW, and the guy launched into a profanity-laced tirade, which I acknowledge is really the best kind of tirade but which is still not something you want to be on the receiving end of.

If you’re a pedestrian and have tried the polite please-stay-off-the-sidewalk method with cyclists, let me know how that went. And if you’re a cyclist who rides on the sidewalk downtown, tell me why.

Stand and deliver

And while we’re on the subject of politeness: The other day My Lovely Wife (her again!) was on a Metro escalator when she witnessed an all-too-common scene. “Move right!” a man in a hurry barked rudely to the people below him. When the escalator deposited the crowd at the bottom, it was clear that the person in the way had been a 6-year-old boy holding his father’s hand. They were tourists.

I get annoyed by escalator-blockers, too. But it pains me to think that that kid’s entire trip to Washington may have been colored by a brief, unpleasant encounter in a Metro station. “I remember my first visit to Washington,” he’ll say as a 40-year-old congressman who has just voted to strip the District of some part of home rule. “I was in the first grade and a spittle-flecked guy screamed at me on a Metro escalator.”

We must accept the fact that sometimes we won’t be able to walk on a clogged escalator: Too many people block it or we can’t see the cause of the blockage. (It could be a child or a seeing-eye dog.)

If you can see the cause of the logjam, and it’s just one or two harmlessly clueless people, this is what you should say: “Excuse me. Can I just squeeze past on the left?”

That’s informational without being confrontational. Remember this little aphorism: Do not give people a reason to hate you.

Send a Kid to Camp

This year’s fundraising drive for Camp Moss Hollow, a summer camp for at-risk kids, ends Friday. Please consider making a contribution. Donate at www.familymattersdc.org. Or send a check, payable to “Send a Kid to Camp,” to Family Matters of Greater Washington, 1509 16th St. NW, Washington, D.C. 20036, Attention: Accounting Department.

Clyde’s is providing gift certificates to its fine restaurants. If you donate $200 to $299, you’ll receive a $25 gift certificate. Give $300 or more, and you’ll get a $50 gift certificate. (Certificates will be mailed in August.)

Err base

In Monday’s column, I misplaced Randolph Air Force Base by about 1,000 miles. Randolph is not in Mesa, Ariz. It’s outside San Antonio. The base my father was stationed at in Mesa was Williams Air Force Base.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/johnkelly.