They are signs of both the tourist season’s long-awaited arrival and Portland’s emergence as a “food destination”: clusters of people enjoying a bite or a drink in the open air at establishments offering outdoor seating.

But the rising popularity of alfresco dining in the downtown area is a growing problem for some in Maine’s largest city.

For Bud Buzzell, a 72-year-old sight-impaired resident, the familiar sidewalks near his Congress Square home are increasingly a frustrating and dangerous maze caused by restaurants he contends are not providing the required 4 feet of pedestrian space.

“One is more or less copying the other and I’m very upset about it,” Buzzell said of the restaurants expanding into the sidewalks of his neighborhood. “And I know a lot of blind or visually impaired or disabled people who are very upset.”

Buzzell is not alone is his concern. Wheelchair users, stroller-pushing parents and other pedestrians have lodged official complaints about restaurants overextending into the sidewalk space in violation of their permits and city ordinances. City officials insist they are aware of the issue.

“We will investigate all concerns about the sidewalk tables and chairs not being within the proper limits. We take it very seriously,” City Manager Mark Rees said during a recent City Council meeting.

It’s an example of growing pains in a city whose thriving restaurant scene has put Portland on the national map as a “foodie city,” drawing more tourists and new residents alike to the region.

The number of outdoor seating establishments has more than doubled during the past decade.

Chuck Fagone, who is responsible for enforcing Portland’s outdoor seating permit requirements, said he typically receives one or two complaints a week during the spring and summer. The city did not start keeping an official log of complaints until last year, but Fagone said the trend is upward.

When complaints come in, Fagone said he visits the restaurant and tries to “educate” the managers if he finds the outdoor seating is taking up more sidewalk space than their permit allows. He has yet to issue a summons – a $75 fine – to a restaurant, but Fagone said he may this year if there are repeat offenders.

“We don’t want to have to do that,” said Fagone, who handles code enforcement and inspections for the city. “We recognize that restaurants are a big part of business in Portland. But we want to make sure that pedestrians have good passageway.”

The stretch of Congress Street near Congress Square Plaza is dotted with restaurants offering outdoor seating, but that can also pose a challenge to the disabled, particularly during busy times of the day.

On a recent afternoon, Buzzell had little problem navigating the space outside of Otto Pizza with his guide dog, Josie, but on another day part of the open sidewalk was interrupted by an A-frame menu board. A block away, Buzzell had to cautiously pivot around a planter marking the beginning of the popular outside seating area of Taco Escobarr.

Otto Pizza co-owner Mike Keon said he and other managers instruct staff about the space requirements, but he acknowledged that the stretch of Congress Street near Congress Square can get tight with all of the foot traffic. Customers sometimes move the tables or ropes farther out into the sidewalk to give themselves additional space, which the staff then has to move back.

Overall, Keon said outdoor seating is a popular draw.

“It’s a great benefit” to the business, he said Friday. “It is sort of an advertisement that you are open, and on a great day like today, people want to be outside.”

A representative for Taco Escobarr could not be reached for comment Friday.

Last year, 37 establishments located primarily in the Old Port or on Congress Street were permitted to seat patrons outside. Permits must be renewed annually, so the 26 permits issued so far this year likely represent an incomplete list.

City ordinances require restaurants to keep at least 4 feet of clearance between outdoor seating areas and the potential closest obstacle, be it a tree, a bike rack or the curb. To make sure restaurants know the boundaries, the city installs 3-inch metal pegs in the sidewalk.

Steve Hewins, executive director of Portland’s Downtown District, a nonprofit that promotes the city’s downtown, said he periodically receives complaints about sidewalk access because of outdoor seating. Hewins said he talks with the restaurant operators to remind them about the requirements.

Cities across the country are similarly attempting to balance the demand for outdoor seating with the needs of pedestrians, Hewins said. He has fielded calls from counterparts in Burlington, Vermont, and Boulder, Colorado, asking about how Portland is attempting to strike that balance.

For Portland, alfresco dining during summer months is becoming part of the city’s aesthetics as it seeks to develop a “brand” as a “walking city.”

“We are cooped up so much of the year here in Portland, so when you have the opportunity people want to eat outside,” Hewins said. “I think we need to enforce the (pedestrian) requirements … but at the same time don’t discourage outdoor dining.”

City officials say the issue is on their radar screen.

One member of the public raised the issue of outdoor seating creep – especially on Congress Street – during City Council consideration of a request for a new permit last week. The council voted unanimously to grant the permit to Benkay Japanese Restaurant on India Street, but three council members stood up afterward to express concerns about obstructions on sidewalks and urge residents to report problems to City Hall – including with cellphone pictures, if possible.

“Many times, most of the sidewalks – and sometimes in the Old Port the entire sidewalk – have increasingly been blocked by outdoor seating,” said Councilor Kevin Donoghue. “That is not permitted and our ability to counter that … is inadequate at this time.”

Later in the week, Rees, the city manager, raised the issue during a meeting with the Portland Disability Advisory Committee, whose members are working to address a broad range of accessibility issues in the city. Rees asked the committee to compile a list of particularly problematic establishments or areas and submit it to his office.

Committee member Renee Berry-Huffman said Thursday that it is a growing issue that affects more than simply Portland residents who, like herself, rely on wheelchairs or powered chairs. The key will be educating both the restaurant-going public and the restaurant owners, she said.

“They should give just as much consideration if it was a baby stroller,” said Berry-Huffman, who uses a powered chair. “They are taking up too much of the sidewalk and it is impeding passage.”

Back on Congress Street, Buzzell was obviously uneasy as he gingerly walked by one restaurant’s alfresco seating area. Although the establishment, Congress Bar & Grill, appeared to meet the city’s 4-foot requirement, the uneven sidewalk around an old tree planter box is the type of surface that can trip up the vision-impaired or catch the wheels of a chair or baby stroller.

A member of Portland’s Disability Advisory Committee, Buzzell has taken on the role of advocate for Portland residents who, like him, want to make sure the city’s sidewalks are safe for everyone.

“These sidewalks are very bad,” he said while navigating another stretch where he has seen people trip. “I don’t like people walking on them and getting hurt.”