RALEIGH, N.C. - On a January night, under cover of darkness, Matt Tomasulo and friends dared to commit a subversive act: They placed 27 signs at three intersections in Raleigh, advising people how long it takes to walk from one destination to another.

"It's an 18 minute walk to Glenwood South," read one sign in purple, the color Tomasulo chose for commercial interests. "It's a 7 minute walk to Raleigh City Cemetery," read another in green, designated for public spaces.

The signs were so well-made that city officials assumed someone had authorized them. And Tomasulo and the two friends looked so innocuous that a police officer who passed by that rainy night didn't question them. "He stopped and read it and realized it wasn't advertising and just kept walking," Tomasulo said Wednesday.

But leaders in Raleigh, which has a population of about 400,000, weren't involved in the project. Instead, the signs were part of a movement called guerrilla or tactical urbanism, where citizens change their cities, often without official approval. They were also part of Tomasulo's master's project in city and regional planning at the University of North Carolina at Chapel Hill to create an advocacy campaign called Walk Raleigh, designed to promote healthier communities through walking.

The project is "just offering the idea that it's OK to walk," said Tomasulo, 30, who's getting a dual degree from UNC and N.C. State University in landscape architecture. "It's not telling you to walk. It's just offering the idea that it's OK, and it is a choice. I think that's the biggest issue -- people just don't even think about walking as a choice right now. Even if you can't walk to get your groceries, I think you can still choose to walk each day."

The signs - complete with QR codes that allow pedestrians to download directions on their smartphones - stayed up for about month before city officials learned of their unauthorized origin and took them down.

But the signs -made of corrugated cardboard and vinyl so they're weatherproof - went back up again this week as part of a 90-day pilot program to evaluate the public's response. Meanwhile, the city of Hoboken, N.J., is considering adapting the signs for that city, and Tomasulo has heard from people in other countries - Australia, Germany, France, Great Britain - who are also interested. A group in Tennessee is considering doing something similar to what Tomasulo did - placing signs around a city one night with directions that encourage walking.

All that has led Walk Raleigh to blossom into Walk (Your City) and helped Tomasulo develop a website where cities can create their own signs. He's raised almost $8,000 online and gotten nibbles from companies that want to partner with him. Tomasulo also owns a company called CityFabric, which sells totes, posters and T-shirts with the digital map of various cities.

Some of the original signs are located around the corner from the office of Raleigh planning director Mitchell Silver, whose staff assumed they were part of a city program since they didn't advertise anything as most illegal signs do. When he learned the signs had to come down, Silver looked for a way to fast-track the project and get them back up.

He fell in love with Tomasulo's idea, which embraced the city's plan to encourage both healthier living and walkability within Raleigh. "I've never seen this level of civic participation from this generation since the 1960s, when I grew up," said Silver, who's also president of the American Planning Association. "I wanted to endorse that level of creativity and innovation."

Hoboken, a city of 50,000, is in the planning stages of adapting Tomasulo's Walk Raleigh signs to fit that city, Mayor Dawn Zimmer said. "We want visitors to enjoy the city, but we don't want them to drive. Parking is really difficult."

The city wants to see if the signs could promote more than walking. "They're a creative, innovate, flexible and cost-effective way of promoting walking, biking and public transportation," said Zimmer, adding that the city may have a pilot program going by this summer.

"More and more, people want to walk," said Silver. "The new American dream is a sidewalk."