Longmont - It's not quite The Truman Show, but it was designed by the same people who built Seaside, the Florida community that served as the movie's backdrop.

Therefore, it's quite easy to get the sensation of being in a theme park when strolling the streets of Prospect, an 80-acre community off Pike Road west of U.S. 287.

Designed in the tradition of "new urbanism" or "traditional neighborhood design," it embraces a philosophy that revives the neighborhood fell of the 1920s and '30s. New urbanist communities feature designs that make being in a car feel unnatural. Wide front porches, picket fences, and narrow, tree lined streets invite pedestrian travel.

The community also encourages home-based businesses and small retail stores so people can live, work and shop in their neighborhood.

Maybe it should be called Pleasantville.

But there's one thing that all developers of such projects agree on - the concept is experimental.

"This is like a great big classroom," said John "Kiki" Wallace, the developer at Prospect, looking out the second-floor window of the residential sales office onto a "Leave it to Beaver" landscape.

New urban developments, while innovative and apparently popular judging by Prospect's high housing prices - single-family homes start at about a quarter million dollars - can be tricky to pull off. They require "a reorientation of our development standards," said city planning director Brad Schol. "Most (suburban neighborhoods) are patterned after a real strong society that exists and relies on the auto."

Developments such as Prospect have narrow streets, behind-the-house parking, and tight lots that result in high density. This poses code problems for city planners and headaches for the fire department and trash haulers.

"People in the city were wondering what's going on," said Greg Rosener, a Prudential LTM marketing agent for Mill Village, a business park that integrates new urbanism ideas. "New urbanism, has taken the re-writing of regulations. ... The city's made all sorts of adjustments for this."

"It is definitely more complicated" than more conventional developments, said Sue Juntunsen, owner of Huntley & Co., which is building houses at Prospect.

Schol said that since the end of World War II, most municipalities developed a standard planning and zoning code based on the assumption that most people would drive elsewhere to work and shop.

This translated into wider streets and houses whose most prominent features were concrete driveways and drab garage doors.

"My own personal opinion is that I'm glad to see the construction and development and design industry moving back toward a concept that was more to human scale and makes a more livable environment," said Schol.

Although the sentiment seems to be fairly uniform, new urban developments are still in their infancy. And whether they will work out as the developers hope remains to be seen.

"We're fortunate that the market held on or we would be in big trouble," said Rosener of Mill Village Business Park.

The development at Colorado Highway 119 and County Line Road is a long-awaited project that borrows some new urbanism ideas and applies them to Longmont's reputation as a regional destination for high-tech and manufacturing firms.

The project includes three buildings with about 200,000 square feet of "flex-space" appropriate for research and development or small high-tech firms, and about 340 residential dwellings on 120 acres.

After nearly five years of false starts and roadblocks - mainly from zoning regulations, financial troubles and partnership disputes - Mill Village will break ground sometime in April on the commercial buildings.

Rosener said he's approached a number of businesses about the concept of moving into the space and having some of its employees live in the adjoining residential section. Though he said the response has been favorable, none of the buildings has been leased yet.

Rosener admitted that for the project to be a complete success, it requires synergy between commercial and residential development and cooperation with municipal authorities.

There's little doubt that the project will eventually be successful, even if the employee/resident plan doesn't work out, said Barry Ruehlen of Pierce Builders Inc., the contractor building the commercial property. Pierce co-owns the 17-acre commercial parcel with project developer Roger Pomainville, who was out of the country and unavailable for comment.

"I don't think that it's necessary that we find a company that wants to relocate their people or push their people" into buying a home at Mill Village, said Ruehlen. "I think what's important is that the options are there.

"The success of one isn't based the success of the other," he said.

However, he added, "I do put a little weight on the residential aspect working because it's going to give us a few more chips to play."

Rosener said the developer is aiming to fulfill the promise touted on Mill Village's brochures, that the project will become a "neighborhood workplace".

John Cody, president of the Economic Development Association of Longmont, is helping push the concept to businesses interested in locating in Longmont - but he's not sure it will fly.

The idea of self-sufficient neighborhoods is becoming popular, he said, "but how much they'll be able to rely on the fact that their labor force will live in their community remains to be seen...

"Time will tell. I really don't know."

Another aspect of the learn-as-we-go nature of new urban developments involves affordability. Even though projects such as Prospect and Mill Village tout reviving a sense of community as a major selling point, that community comes at a premium.

Prices for Mill Village dwellings range from $110,000 for condominiums to more than $200,000 for duplexes.

Current price ranges for single family houses at Prospect starting mid-$200,000.

Both projects received city approval with the stipulation that a percent of the housing be deemed "affordable" by the city's standards.

But the definition of affordable at the time the projects were approved was vague at best and didn't specify if the affordable units are required to be for sale or rent.

Wallace said Prospect is meeting the condition by requiring 10 percent of its homeowners to rent their garage top apartments as affordable housing.

But they'll be required to do so only until certain time-specificitions set by the city are met.

Nothing out here will be permanently affordable," Wallace said.

According to current county guide lines, landlords can charge $863 per month, including utilities, to people who make 80 percent of the medium income.

But because each affordable unit will be owned and managed by an individual homeowner, the city's not sure how to enforce the rules.

"I'm not exactly sure how we're going to work that out," said Kathy Fedler, community development block grant planner for the city. "I'm not sure what enforcement mechanism the city will have with individual property owners."

"I don't think that particular project hit the nail on the head" regarding the affordable housing requirements, said Schol. "But affordable housing takes many different forms."

Schol said the city is still trying "come up with the details" about enforcing the affordable housing requirements.

"We're beginning to understand some of the best plans for regulations," he said, noting that unique developments often require unique solutions.

It's unclear how the city will establish the guidelines for the affordability requirement for Mill Village, hopefully we won't have a situation like Prospect," said Fedler.

Hiccups and learning curve aside, Phil Marti, a spokesman for Pratt Management & Co., said he applauds the developers of new urban projects as pioneers.

"While the risks are great, the rewards can be great, too," he mid. "We appreciate those who are willing to be bold and we wish them well in their endeavors."