In Gwinnett County, it’s no longer enough to have nice houses and good schools, city officials say. People in the suburbs also want to walk downtown for a meal or a latte or just to hang out in the park.

So Gwinnett cities along the I-85 corridor have spent millions to improve their downtowns and even build brand new town centers in efforts that go beyond the brick sidewalks and wrought-iron street lights that mark many downtown rehabs. City officials say the spending is an investment in their cities’ future.

Building a downtown is a long-term investment, and measuring the immediate return isn’t simple. But rising relative property values, falling vacancy rates and citizen survey results suggest the investment may be paying off.

Besides, it’s usually cheaper to supply city services to dense downtowns than to scattered strip malls and subdivisions, said Danny Bivins, a University of Georgia faculty member who specializes in downtown development.

“Your investment in your downtown is maximizing the investment that you’ve already paid for,” he said.

Some of the Gwinnett cities’ downtown development work has been supported by grants from the Atlanta Regional Commission. But local taxpayers are footing most of the bill.

Norcross spent nearly $15 million over the past 8 years on parks, a downtown community center and other projects.

The city of Suwanee spent about $17 million since 2001 to build a brand new downtown from scratch and private developers spent millions more.

And the 2-year-old city of Peachtree Corners plans to embark on a similar project — and has already borrowed more than $11 million.

In the 19th century, Suwanee’s downtown centered on the railroad. But by 2000, the small strip of antique shops, churches and houses by the tracks was too small for the growing city. After a series of community meetings, city leaders decided Suwanee needed something more.

Suwanee residents approved a bond referendum in 2001 to finance the purchase of several city parks, including the 10-acre parcel on Buford Highway that today is the core of the city’s new downtown.

On part of the land across the tracks from its original downtown, Suwanee built a park with trails, an amphitheater, a splash fountain and a City Hall. The city sold the rest of the land to a private developer who agreed to build in line with the city’s downtown goals. That means a semicircle of stores and apartments with wide sidewalks curving around the park. A separate housing development sits behind the city development.

Today, the privately developed commercial and residential areas are worth nearly $77 million. The new commercial area has one of the highest values per acre in the county. Thousands of people visit Town Center on any given weekday to shop, eat or hang out in the park, city officials say. And a 2012 city-sponsored survey found that nearly all Suwanee residents had visited the city park at some point.

When the city bought the land in 2002, it was a vacant lot on the corner of a busy road, the perfect spot for “insert your favorite big-box store here,” said Denise Brinson, Suwanee’s economic and community development director.

“Not that there’s anything wrong with that,” she said. “But that doesn’t make a good downtown.”

Peachtree Corners, Gwinnett’s newest city, recently bought 11.5 acres across the street from the outdoor mall that serves as the city’s de facto downtown. Peachtree Corners will soon hire a planner to help create its own downtown plan, but is already looking to Suwanee as one possible model, Peachtree Corners community development director Diana Wheeler said.

Duluth opened a new $13 million City Hall in late 2008, converted the city-owned Red Clay Theatre into a professional theater, and hired Eddie Owen, founder of Eddie’s Attic in Decatur, to operate a live music venue in the space. Over the past three years, more than 35,000 people have visited the theater, Mayor Nancy Harris said.

The city of Norcross’ downtown is centered on the train tracks that gave the city life nearly 200 years ago.

Over the past 8 years, the city spent about $7 million to turn the town’s original baseball diamond into a park with walking trails and a fountain: $3 million on a welcome center, $1 million on another downtown park and $3 million on sidewalk improvements and other downtown public works projects. And Norcross recently spent about $530,000 on land for a new downtown parking deck.

Nearly all of it was paid for with the city’s share of Special Purpose Local Option Sales Tax proceeds.

Like Suwanee, Norcross bought now-vacant land around downtown’s Lillian Webb Park and hopes to sell it to a private developer to build stores, restaurants and offices, and possibly homes too.

Six years ago, about 40 percent of downtown storefronts were vacant, Norcross marketing manager Tixie Fowler said. Now nearly all are occupied.

One recent weekday afternoon, Morgan Bultman drove from Ansley Park to downtown Norcross on an errand — and ended up shopping for clothes on Main Street.

“I loathe shopping in the city, dealing with the traffic and the malls,” she said. “Here it’s so much easier, and the atmosphere is nicer.”

And at Zapata Tacos and Tequila Bar at the northern point of downtown Norcross, business has improved every year, even during the recession, manager Victor Ponce said.

“This is someplace a lot of people want to be,” Ponce said.