The signs of happiness are right in front of you. You’ll see them as you drive into the city on a Monday morning, steeling yourself against another day in front of a computer screen.

We’re talking about four poster-board signs held by four relentlessly optimistic people, a sort of pep squad for the beleaguered office drone. The signs on this day read: “Honk if you love someone!”; “Be happy”; “Don’t be so hard on yourself”; and, of course, “Smile!”

The signs are the work of Massoud Adibpour, 29, of Columbia Heights. He and friends have spent the past four Monday mornings holding them up in front of rush-hour traffic, to a cacophony of honks. They stood on the Mall at 14th Street, the best place to catch commuters coming across the bridge from Virginia to begin another bleary-eyed Monday. Passing bicyclists dinged their cheerful bells. Pedestrians gave a thumbs-up. Unmarked cop cars blew their cover by flashing their lights. Drivers of 18-wheelers yanked on their air horns, loud enough for a tugboat. Most people smiled.

But no one smiled more widely than Adibpour and his friends.

“No one wants to go to work on Monday, so we wanted to brighten people’s day,” he said. “D.C.’s really stressed out, so I wanted to spread a little bit of happiness in the city. I think it can go pretty far.”

He aimed to get 350 people to honk, beating his group’s previous record of 307. “If people aren’t honking, they’re waving or smiling.”

Or yelling.

“I’m in love with you!” a driver screams out to Maggie Cannon, 24, who is holding “Honk if you love someone.”

* * *

Adibpour is a human Bobby McFerrin song repeating in your head. He emanates positivity, enough to make Woody Allen types wince. He speaks in the motivational mantras of the posters that hang in elementary school classrooms, tossing off cliches like “The sky’s the limit.”

With his signs, and without knowing it, Adibpour has engineered what psychologists in the science of happiness call a “positive intervention.”

Yes, there’s a science to happiness, and it has its own math: For each negative encounter in a day, people need five positive interventions to keep up their happiness quotient, says Caroline Adams Miller, an executive coach and author of “Creating Your Best Life.”

But for that dynamic to work, people have to respond positively to the intervention. “It is a voluntary behavior or thought change that takes you from either negative to neutral, or neutral to positive, or positive to even more positive,” Miller said. In other words, scowl at Adibpour and his sign-toting friends and you’ll have to put up with the rest of your miserable day.

And even though the group’s signs provide only a brief moment of cheer, people shouldn’t write off the good effects, Miller said. A sign that jogs feelings of gratitude or contentment triggers a mind-set that will encourage good feelings throughout the day.

“Those fleeting moments . . . add up throughout the day to generate other positive emotions and offset the negative ones,” Miller said.

* * *

Since February, Adibpour has been plastering signs around the District, mostly in Columbia Heights, Adams Morgan and the most ulcerative of all areas, K Street. They’re all encouraging, scrawled in his quirky hand-lettering — e.g., “Life is short. Take chances.” Some are interactive, like the sign that reads, “Take what you need” with little tear-away strips of paper that say “love” and “luck.”

Adibpour’s sign offering love and luck already has caused a ripple effect of happiness. After seeing the sign in Columbia Heights, former neighborhood resident Sophie Miller constructed a giant chalkboard with the prompt “Before I Die . . . to encouraged passersby to fill in their bucket-list hopes and dreams.

Happy minds must think alike. Last Monday afternoon, Adibpour set up a table at the Columbia Heights Metro stop with bucket-list sheets and invited commuters to jot down their goals and desires. Responses included “Cure HIV,” “Be a celebrity make-up artist” and “Meet my dad.”

Adibpour has his own 100-item bucket list, to be completed by May 29, 2032. “Having a physical copy is important,” he, pulling the water-stained list out of his wallet.

Some of his goals, which also are listed on his blog: Crash a wedding, travel to North Korea, visit family in Iran and see Daft Punk in concert.

But Caroline Adams Miller points out that bucket lists aren’t just fodder for a Jack Nicholson/Morgan Freeman buddy flick. Life-goal setting is directly correlated with happiness, she says.

“Proactive people who lead forward-looking lives, who are connected to other people, giving back and going out of their comfort zone are the . . . things you find when you study happy people,” Miller said. “They don’t live lives of ease; they have a certain amount of grit.”

* * *

Adibpour, who works as a concert promoter and director of contracts at the 9:30 Club, began his happiness campaign after a long backpacking trip abroad. He had graduated from James Madison University in 2005 and had gotten a good job as a government contractor for ICF International. The money was nice, but he hated the work — so, to his parents’ chagrin, he quit and took off on an eight-month journey to Australia, Thailand, Cambodia and elsewhere in Southeast Asia. He came back $10,000 in debt (paid off, thanks in part to some time spent living with his parents to save money) but reawakened to his life’s potential.

“I’m really simplified now after my backpacking trip. I appreciate so much more. I’m a happier person in general,” he said. “Money can always be replaced.”

What about the people who don’t have the resources to travel?

“Quit your job,” he says.

What about the people who can’t quit their jobs?

“Why can’t you quit your job?”

Some people need the money.

“You can make cuts.”

There’s a bit of Millennial myopia here: Most people can’t afford to quit their job and live off of credit cards and hang out in Laos for a few months, and this appears to be something that Adibpour hasn’t thoroughly considered.

Still, Adibpour’s attitude toward work seems to be in sync with that of his generation, many of whose members believe in flexibility and balance rather than nose-to-the-grindstone workweeks.

But not everyone will be receptive to Adibpour’s signs.

“You can’t just tell somebody to be happy,” said Meghan Keener, a positive psychology consultant who earned her master’s degree at the University of Pennsylvania. “The meaning should come out of you, not the sign itself.”

Adibpour agrees. “People need to decide for themselves, ‘What makes me smile?’ ”

* * *

“This feels so good. I want to come back next week,” said Meghan Pugliese, 25. She was holding the “Don’t be so hard on yourself” sign, and the honks were coming so frequently that, although the group had lost track, the members were certain that they had reached their goal of 350.

Bonnie Culpepper, 25, who held the sign that said “Smile,” said the project has had an effect on her studies as a master’s candidate in marriage and family therapy at Virginia Tech.

“Part of becoming a good therapist is becoming more positive yourself,” she said. She’s held signs with Adibpour for the past four weeks. “I’m floored by how easy it can be to spread positivity.”

Though Adibpour calls his project “Make DC Smile,” he hopes to come up with a more universal name so he can spread the love to other cities.

Those cities may need his help more than this one: Although Adibpour characterizes the District as a negative place, full of overworked government automatons, research suggests otherwise. Washington comes in second on the 2011 Gallup Healthways well-being index, behind San Jose, Calif. Are too many hours spent at work or sitting in traffic? Sure, but the District rates high in emotional and physical health. Unemployment is low, and the city is full of culture, amenities and lush expanses of grass and trees.

“There’s something called social contagion, where you’re as happy as the people around you,” said Miller, the executive coach, a fifth-generation Washingtonian. “There’s plenty of positivity in Washington, and there’s a lot of hope.”

* * *

Adibpour has big hopes for his project — getting 1,000 people to honk in one morning, taking his message across the country — but his day-to-day goal is quite manageable: He just wants to get one new person to participate in his sign-holding each time he goes out. Last Monday, that person was Ivan Price, a 59-year-old visitor from Rocky Mount, N.C., who was in town to see the Smithsonian National Museum of American History. Price walked past the sign brigade and called out “Honk honk!” before circling back to take some pictures. Adibpour recruited him to hold the “Honk if you love someone” sign for a few minutes.

“It’s nice to see friendly faces,” Price said. “It gave me a very warm feeling.” He sang a few bars of the Beatles’ “All You Need Is Love.”

Someone honked. “We know you love somebody!” he yelled to the traffic. Another honk.

Print out some happiness signs for your office on the Style Blog. Has one of the Make DC Smile signs inspired you? What would you put on one of Adibpour’s happiness signs?