Double-decker tour buses are coming to Boston. But rivals say not so fast.

Longtime tour operators and their allies are urging Mayor Wu to overturn a Walsh-era rule change that would allow the buses in the city.

Two entrepreneurs want to bring double-decker tour buses to Boston this summer. Now their rivals are trying to hit the brakes.

Open-top, two-level buses, though popular in many other cities, were apparently discouraged under Tom Menino’s long tenure as mayor. Maybe not anymore. Last fall, the city’s main tour operators say they learned double-deckers could hit the road here soon. Now they’re urging Mayor Michelle Wu to idle those plans.

Driving the controversy is a little-noticed 2019 rule change by the Boston Police Department — which oversees hackney licenses — to increase the dimensions and weight of tour buses allowed on the city’s streets. Leaders of three longtime local tour operators — Old Town Trolley Tours, CityView Trolley Tours, and Boston Duck Tours — said they only learned about the change last fall. In November, they sent a four-page letter to Wu, then the mayor-elect, criticizing the two-year-old change and the Police Department’s apparent decision to allow double-deckers without seeking public input.

Then, in late January, the Back Bay Association and two other civic groups sent a letter to Wu, expressing concerns about the safety of the larger buses. In that letter, the association asked the mayor to suspend the 2019 rule change until a public review can be conducted.

“The taller buses have been something that many of us have been concerned about and pushed against over time,” said Back Bay Association president Meg Mainzer-Cohen. “They can provide all kinds of problems with traffic [while] the safety for pedestrians and bikes is diminished. We just felt there needed to be some kind of a public process, and there wasn’t any.”

That appears to be changing. On Tuesday, a Wu spokesperson confirmed that city officials will meet with tour operators and community organizations to better understand the plans and the various parties’ concerns, and to ensure bus tours won’t hurt the city’s transportation system or quality of life.

Under the old rules, sightseeing buses in Boston could be no higher than 13 feet, 4 inches, and no longer than 36 feet. Those dimensions were broadened in June 2019 to 14 feet and 42 feet, respectively. The maximum weight was increased as well — to 38,000 pounds, up from 26,000 pounds.

Why the change?

That question seems to be a matter of some debate. When asked by the Globe, the Boston Police Department couldn’t provide an answer. The incumbent operators argue the decision was to give a green light for double-decker buses. But the two entrepreneurs behind one new double-decker business say it was actually done to accommodate Old Town Trolley buses that were already over the old weight limit.

Tom O’Connor and Steve Caplan, co-owners of Historic Boston Tours, hope to launch double-decker service in the city this summer if COVID-19 sufficiently recedes. (They originally planned to do so two years ago, but then the pandemic hit.) They said the rule change was not made on their behalf. But it will be helpful: O’Connor said the double-deckers he plans to use would be 39 feet long, and weigh up to 33,000 pounds. (Their height would not exceed the old limit.) He said the company, which has hired former city and state transportation official Thomas Tinlin as a consultant, had originally intended to use smaller buses that fit under the old rules, until they found out in 2019 about the new parameters.

“This whole notion that this was done under some subterfuge or behind-the-scenes kind of methodology is absolutely not true,” O’Connor said. “To me, this is the competition recognizing that we’re about to come in, post-COVID, with double-decker buses and they are very concerned that’s going to affect their economic interests.”

O’Connor and Caplan are also in talks with Big Bus Tours — a British company that operates its own double-decker routes in 20 cities worldwide — to be a potential licensee. Big Bus also has a licensing arrangement with an independent operator in Philadelphia, said executive vice president Julia Conway, and a similar deal in Boston would give Historic Boston Tours access to the Big Bus website, name, and marketing.

The specter of a Big Bus Tours arrival was raised in the November letter from the three incumbent tour operators. They noted that these open-top, double decker buses had been kept at bay in Boston in the past because of safety concerns (chiefly involving the possibility of passengers getting hit by tree branches or low-clearance bridges), and that their industry is still in “recovery” mode in Boston, making it hard to see a business need for more sightseeing companies in the city.

In interviews, top executives at the three preexisting tour operators say this is less about fighting off a competitor, and more about a critical rule-making process being as above board as possible. Mike Thomas, president of CityView, said double-decker tour buses haven’t run in Boston in roughly four decades.

“It was an understood policy that double-decker buses would not be happening,” said Cindy Brown, CEO of Boston Duck Tours and a member of the Back Bay Association board. “There are a lot of questions that could be addressed in an open forum that never were.”

Chris Crompton, general manager of Old Town Trolley, confirmed that about three quarters of the vehicles in his 40-bus fleet weigh up to 32,000 pounds, including passengers, meaning they would not be legal under the old rules. Crompton, who came to Boston in late 2019, said his vehicles were annually renewed by the Police Department’s hackney division without any problem; he said he only found out those buses were not compliant with the old rules last fall, when he learned about the new rules. He argues that any major change should be done in an open and formal process, to gather input from the public and the industry, even though his company benefited from the 2019 adjustment.

“I’ve got no issues with people starting up a business [but] it’s got to be a level playing field,” Crompton said.

Galen Mook, executive director at the MassBike advocacy group, said he signed the letter with the Back Bay Association because he believes these kinds of decisions should not be done “in a vacuum driven by industry, and more done in a public setting that takes safety as a paramount concern.”

Besides, Mook said, he would argue that tourists would be better served by missing the bus entirely.

“The best way to see Boston is on foot or on bike,” Mook said. “We’re [called] a walking city for a reason.”