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Do new signs on 16th Street NW point in the wrong direction?

A lighted sign on the side of 16th Street NW in Washington is meant to indicate that the two right lanes are open. But shouldn't those green arrows be pointed up, indicating the flow of traffic, rather than down? (John Kelly/The Washington Post)

“The Manual on Uniform Traffic Control Devices for Streets and Highways” is about as scintillating as its title suggests. But that doesn’t mean the book, published by the Federal Highway Administration, isn’t important. Just imagine if U.S. municipalities decided to freestyle their road signs and other traffic aids. The result would be chaos.

And it’s to the MUTCD — as it’s known — that the District Department of Transportation directed me when I pointed out that some of its new signs on 16th Street NW are wrong.

No they’re not, said DDOT.

Yes they are, I said. I’ll let you be the judge.

At issue are what’s known as electronic lane control signs. Cities employ these when the direction of travel on a lane changes during the day: into the city in the morning commute, say, and out of the city in the afternoon commute. Motorists have to know whether the lane they’re in will speed them toward their destination or result in a head-on collision.

This can be done with language — lighted signs that read “Use 2 lanes” or “Use 3 lanes,” as was previously done on 16th Street NW — or with symbols. A green arrow means the lane is safe to drive in; a red X means “here be danger.” Both types of signs can be altered depending on the time of day. That’s why they’re called “variable,” as opposed to “static.”

DDOT installed new signs on 16th Street NW recently, changing from words to symbols. The signs are mounted on both sides of the road every few blocks from Columbia Road to the bridge over Rock Creek. The fancy new LED signs can be programmed to show green arrows, red Xs and/or a bus icon (for the bus-only lane).

When I first saw them lit up, something struck me as odd. The arrows point down, not up. To me, it looked as if this indicated traffic in the right two lanes was coming toward me. Was I suddenly in England, Japan, Malta or any of the other countries that drive on the left?

I asked Jeff Lindley, chief technical officer at the Institute of Transportation Engineers, for his take on the signs.

“I know what they’re trying to convey here, but I understand why this is inconsistent, because most all traffic signs that are side mounted — not over the lanes — would have the arrows pointed up,” Lindley said.

The folks at DDOT pointed me to the aforementioned MUTCD, specifically Section 4M.01, Application of Lane-Use Control Signals. They also sent a link to a photo of lane-use control signals on Colesville Road in Silver Spring. But neither of those applies to what’s going on on 16th Street.

I will quote that section of the MUTCD, with emphasis added: “Lane-use control signals are special overhead signals that permit or prohibit the use of specific lanes of a street or highway or that indicate the impending prohibition of their use. Lane-use control signals are distinguished by placement of special signal faces over a certain lane or lanes of the roadway and by their distinctive shapes and symbols.”

Elsewhere, the MUTCD reads: “A steady DOWNWARD GREEN ARROW signal indication shall mean that a road user is permitted to drive in the lane over which the arrow signal indication is located.”

So a downward green arrow is okay over a lane.

That’s what the Silver Spring photo showed: signs over the road, with green arrows pointing downward, meaning “This lane is open to you” and red Xs, meaning “This lane is closed to you.”

The District doesn’t have overhead lane-control signals. It has signs by the side of the road. The reason it doesn’t have overhead signs, DDOT told me, is because the city’s historic preservation office said signs hanging across the roadway would spoil the historic views down 16th Street.

I get that. I just think the arrows on the new signs are wrong. The signs illustrate a simulacrum of traffic. The downward pointing arrows make it look as if vehicles in the right lane are coming at you.

Lindley has been a traffic engineer for 42 years. He said, “I think the most consistent interpretation of what is in the manual is that the arrows should be pointed up.”

The final arbiter, he said, would be the Federal Highway Administration. I checked with them and they sent me the same passage from the manual and a similar photo from Silver Spring. But those aren’t the same as what’s on 16th Street!

Lindley said a good sign “should convey a clear and simple meaning, so that it’s easily understood by motorists. … If two different people that use the street have two different reactions, that’s probably not good.”

You might ask: Can’t the arrows simply be programmed to point upward? Well, looking closely at the lightbulbs on the signs, it looks as if they can only point down.

Born under a bad sign?

Have you encountered a bad, confusing or hard-to-see sign in the Washington area. Send the details — and a photo, but only if it’s safe to take one — to me at Put “Sign” in the subject field.