SOUTH PORTLAND — Seventeen years after the Casco Bay Bridge replaced the Million Dollar Bridge, the Knightville neighborhood is becoming what many people hoped it would.

The larger span pushed traffic from Portland directly onto Broadway and stemmed the flow of about 35,000 cars that previously passed through Knightville each weekday. Recognizing a rare opportunity, city leaders passed zoning changes that have transformed what was once a drive-through neighborhood into a mixed-use urban village. Knightville is alive with newer homes and businesses. Condos. Coffee shops. Craftspeople.

And there’s the rub.

Knightville’s new vitality has greatly increased traffic and demand for convenient public parking – something the city had done little to plan for or accommodate until recently. One of few steps taken to address both issues – a block-long, one-way section of Ocean Street created two years ago – has emerged as a focus of controversy for people who live or work in the waterfront neighborhood.

The city established the northbound one-way stretch from E to D streets to preserve 15 diagonal or “pull-in” parking spaces on the block, which includes Smaha’s Legion Square Market and 13 other storefront businesses.

While supporters say the one-way section is necessary to preserve convenient parking for businesses on the block, opponents say it has disrupted normal traffic patterns and diminished traffic safety throughout the neighborhood, especially on residential side streets that run between Ocean Street and Waterman Drive.

“It’s become a toothache over time for people who have to deal with it,” said Paul Trusiani, a Knightville resident and commercial property owner. He’s one of more than 30 people who recently sent letters asking the City Council to return the one-way section to two-way travel for a one-year trial.

Trusiani, who owns two buildings at the intersection of Ocean and D streets, said he believes the one-way section may deter commercial activity rather than encourage it.

He has been at social gatherings where people have told him that they’re annoyed by the one-way and try to avoid it. He has noticed that some drivers get visibly angry when they approach the one-way and realize they can’t continue driving on Ocean Street.

“They bang a right on D Street and speed all the way down to the playground,” Trusiani said. “It has created this bizarre traffic loop. I’m not a traffic expert, but to me, it doesn’t make common sense. If it did, we’d have one-way blocks all over the place.”

Soon, a traffic expert is expected to address the Knightville controversy.

Trusiani is a member of an ad hoc committee established last summer to address concerns about Knightville’s mounting traffic and parking troubles. Made up of residents and business owners, the 17-member committee has recommended that the city commission a comprehensive traffic study of the area before doing anything else. The City Council is expected to consider the recommendation early next year.

“A traffic study will help inform whatever we do going forward,” said Jon Jennings, the assistant city manager and economic development director.

Jennings said he’d like to hire an engineering firm that has experience with similar traffic and parking demands outside Maine, to bring a fresh perspective to the issues. A full traffic study, with recommendations on how to accommodate expected traffic increases and maximize parking options, has never been done, even as Ocean Street evolved from an artery that carried about 17,000 vehicles daily in 1994 to about 2,700 vehicles today.

“Developers are very interested in Knightville as a walkable community for baby boomers and young professionals,” Jennings said. “What happens if someone comes in and puts in another 25 units? A traffic study will help us get our arms around this. Because what you see today in Knightville isn’t going to be what you see in five years.”

Some people are OK waiting for the traffic study, including Smaha’s owner Alan Cardinal, an ad hoc committee member who has taken steps to reduce delivery truck travel on D Street. He said any traffic change that would reduce parking on Ocean Street would be unfair to businesses. Because of recent sidewalk improvements, returning the one-way section to two-way travel would eliminate six spaces across from the pull-in spaces.

“Let’s work together and do something that does no harm,” Cardinal said.

Melanie Wiker, a D Street homeowner and ad hoc committee member, said she’s worried that people’s concerns about the one-way section will get swept under the rug. She mounted the letter-writing campaign to return the section to two-way travel.

“Why do those businesses trump everybody else?” Wiker asked rhetorically. “They’re the only ones that the city is listening to and that’s wrong. You had a two-year trial for the one-way. Give us a one-year trial for two-way traffic.”

Sarah Kirn, another D Street homeowner and ad hoc committee member, said she’s willing to wait for the traffic study and hopes that nothing is done to squelch Knightville’s bubbling vitality.

“I get that change is really hard, but you can’t have a mixed-use neighborhood without people driving through it,” Kirn said. “We need to trust the process and come up with a solution that works for everyone.”