Giorgio Sodano was pedalling down Rachel Street when he saw crews building a tree-lined median for the bike lane leading to his Italian deli in Montreal’s Plateau Mont-Royal district.

The first thing he noticed was how much wider and well-protected from cars the new bicycle boulevard was going to be. As a cyclist, he liked it. But a second thought dawned on him as he rolled closer to his store in that summer of 2012: The new path was going to swallow up all the parking on his side of Rachel.

For 18 years, the two or three spots in front of his shop allowed daily commuters to dash in and grab sacks of fresh pasta and tubs of sauce. “I thought, ‘Oh no. They’ve taken our parking. They’ve ruined it,’” Mr. Sodano said.

Mr. Sodano’s Maison des Pâtes Fraîches remains, but it is struggling to stay afloat amid an urban experiment unlike any seen in Canada. Plateau Mont-Royal, the Montreal district that gave the world smoked meat, bagels worthy of the name and Mordecai Richler, is the laboratory for greener, more walkable and cyclable urban design rarely put into large-scale practice in North America.

In the Plateau, the experiment boils down to the block-by-block installation, expansion or improvement of sidewalks, bike paths, patios, benches, parks and plazas, almost always at the expense of the free movement and parking of the automobile.

But after conversations with dozens of merchants and residents of the neighbourhood I call home, after calls to public health and city officials, business and cycling associations, independent researchers and urbanism experts, I find something is missing six years into the Plateau’s status as Canada’s urbanism laboratory: hard evidence it’s working.

A sound experiment has plenty of good data and controls for external factors such as interminable road construction and broader economic trends. This lab sorely lacks those instruments.

Hundreds of business owners such as Mr. Sodano and thousands of car drivers, some of whom live in the neighbourhood, think the experiment is ruining the place. On the other side is Luc Ferrandez, mayor of the Plateau Mont-Royal borough, a smooth-talking, disarmingly frank politician some have tried to dismiss as a radical and an eco-zealot, who happens to be backed by more than half of the voters in the neighbourhood of 105,000 people. Central city Mayor Denis Coderre is among his many adversaries.

Similar arguments are taking place piecemeal in nearly every Canadian city, whether it’s Vancouver planning to put a bike path on Commercial Drive at the expense of parking, attempts to lower speed limits in Toronto to make pedestrians safer, or Winnipeg studying for the umpteenth time whether to finally allow people to walk across Portage and Main.

On the corner of Gilford and Chambord, the street has been split by the Ferrandez administration, a couple of years ago, re-directing the traffic. It is one of the corners seen by many as making it hard for non-locals to come by car in the Plateau district. (Photos by Adrienne Surprenant for The Globe and Mail)

But only in the Plateau will you find a municipal government acting on a long list of such measures in rapid succession. Two thousand parking spots disappeared and thousands of free spots turned into pay. Two hundred sidewalks were expanded at intersections, narrowing streets, slowing cars and, in theory, making crossings safer. Kilometres of car lanes are gone, displaced by cyclists, pedestrians and hundreds of new trees. Streets have been turned into one-way mazes to push traffic to main thoroughfares. Hardly a block in the neighbourhood has gone untouched.

The Plateau is also part of a massive, citywide infrastructure overhaul that has nothing to do with the green project but has torn up most of the major commercial thoroughfares, often repeatedly, in recent years and muddied the evidence considerably.

The theory behind the experiment is this: If a city is made safer for people to bike, stroll, play and lounge outside while drivers are nudged (some say shoved) to leave their cars at home, the community becomes healthier and more vibrant and attractive for everyone.

“We’re being used as lab rats,” said Mr. Sodano, whose Rachel Street has seen many of the new measures brought in by the borough. Combined with disastrous City Hall construction planning, his street has been torn up in three of the past five years.

I’ve lived in the area for 10 years, and the barber who cuts my hair, the bartender who pours my pint, my dentist, pharmacist and french-fry shop owner all say the same: Business is drying up and they mostly blame Mr. Ferrandez.

Mr. Ferrandez was first elected on his plan in 2009 and re-elected with a boosted majority mandate in 2013. Surprisingly, when asked for proof his plan is working, he agrees little hard data exists.

He might have offered select statistics about commercial vacancy rates that show some corners of the neighbourhood are thriving, but the truth is several other streets are suffering badly. The stagnating annual number of new business permits follows a similar trend as the rest of Montreal, but is hardly a bragging point when the Plateau is supposed to be the place to be.

A massive survey conducted every five years by the regional transit authority showed shopping trips to the Plateau actually rose modestly in 2013 from 2008 levels. The Plateau also had more walkers and cyclists and a slight decrease in car use, bucking the trend in most of the city for greater automobile use. But Villeray, a neighbourhood just to the north, showed similar results without a so-called war on cars.

Parc Lafontaine is a key location of Montrealers outdoor life. Ferrandez wants to make it greener.

“We don’t have good data,” Mr. Ferrandez said. “Maybe this is why the discussion goes on and on forever. There’s a huge ravine that separates the parties for and against what we are doing and it’s almost impossible to fill the gap.”

Mr. Ferrandez is sitting on a bench in a small park on Saint-Laurent Boulevard that is on his list of accomplishments. He tore up a street that separated the green space from a church. People now stroll along a stone plaza near a new fountain while they take in the majesty of the cathedral. He’s torn up such pavement to add to parks in several other places.

He points to the one data point he thinks is key: “The one thing that could have sunk the whole project is if property values had gone down. Instead, they’ve gone up and up and up. Real-estate prices are going up faster here than anywhere else in Montreal.”

Many Canadians may not recognize the name Plateau Mont-Royal, but most know of the neighbourhood with its mix of celebrities, famous businesses and walk-up apartments with twisting metal staircases. The Plateau is where tourists find Schwartz’s deli along with the Saint-Viateur and Fairmount bagel shops. The Mile End chunk of the Plateau is where bands such as Arcade Fire found their sound. Leonard Cohen used to haunt the place. It’s the neighbourhood of the iconic Saint-Laurent Boulevard, also known as The Main, which traditionally divided French and English Montreal.

From working-class roots and a 1980s status as a bohemian enclave, doctors, lawyers and entertainers have now gentrified the place, turning multifamily dwellings into open-concept houses with price tags pushing $1-million.

Mr. Ferrandez started out in 2009 with a few key data points he used to sell his plan to Plateau residents. The place was far more dangerous for pedestrians than any other residential neighbourhood, and cyclists were not much better off. About 84 per cent of the 651,555 daily car trips clogging up the neighbourhood were by commuters just passing through. Often they looked for shortcuts on narrow residential streets. Meanwhile, the Island of Montreal was adding 45,000 new cars every year.

My wife and I moved here 10 years ago for the urban vibe, handy transit and easy walk to most places we needed to go. We now have children and use our car more. The parks are indeed better kept, with functioning fountains and updated play equipment. The bike paths and pedestrian crossings feel safer to haul around three small children. But the owners of my favourite shops almost all say they are facing ruin.

Baldwin Park was split in two by Marie-Anne street until 2012, when politician Luc Ferrandez blocked the street between to make the park more secure for children.

In 2012, Mr. Sodano, the Italian deli owner, conducted a survey of 57 businesses on his street. The questions he posed were not exactly scientific, but the responses were unanimous. Logistics had become impossible and business was suffering. The survey provided a baseline for one good data point: Since 2012, four of the businesses have moved, two were sold and eight closed, for a 24.5-per-cent turnover. Among those left, several put up mock “For Sale” signs in the fall to protest all the changes but especially the disappearance of plentiful, free or cheap parking.

Mr. Sodano says forget data. “Look at the street outside, it’s dead,” he said. Mr. Ferrandez vehemently disagrees. “There have never been more people on our streets,” he said near his office on Laurier Avenue.

On Rachel Street, trucks are parked in front of a closing patisserie. Owner Yves Jacot is sending his coolers, pans and other supplies off for liquidation. He blames the experiment. “The rules of the game have completely changed,” he said. “They have no empathy for us.”

Down the street, Maurice Gervais is selling the last of the yarn in his wool shop, an 80-year presence on the street called à La Tricoteuse. The store was run by his wife Janine Couvrette, who died in 2012. He’s taken three years to liquidate all that yarn. “I don’t need to retire to the country now; it’s like the country out there,” he said. “It no longer has the feel of a city.”

Broader economic forces are at play. Experts say many of the troubled businesses would have the same problems if Mr. Ferrandez had never come to power.

Jean-François Grenier, a retail consultant for Altus Group, conducted research for a neighbourhood business association that underlined how retail spending across Quebec is flat while consumer choices have multiplied. Several neighbourhoods now have their own strips with fancy restaurants and popular boutiques. Suburbs have improved shopping and dining. Nobody has to drive to Saint-Denis Street to find a designer dress or pastry. Restaurant sales are flat and bar sales are in steep decline in Quebec – two key, fickle sectors in the Plateau.

The neighbourhood has stagnated in ways beyond anyone’s control. It is one of the densest in Canada, with 105,000 people in eight square kilometres. There isn’t much room for population growth. Higher property values and rents mean greater expenses for business owners and customers alike. Wages in Quebec have stagnated. “There are a multitude of factors – it’s not just a parking problem,” Mr. Grenier said.

Yves Jacot carries the portal of his now-closed bakery Le Petit Fourneau’s portal."The only thing I have left from those 8 years of work is souvenirs." he says.

Jacques Nantel, a professor of retail marketing at the HEC Montréal business school, said merchants need to forget their history as “destination stores” and start catering to the local market. That means more vegetable, fish, meat and cheese shops and fewer designer coat stores, he said. “I’m not a fan of Mr. Ferrandez, but he doesn’t deserve all the tomatoes being thrown at him,” Mr. Nantel said. “Part of the problem here is we are in an information vacuum. Retailers don’t have the data they need to make the hard transformation. And some don’t want to do it.”

Older cities like Montreal “were built for walking, it’s only a brief moment in history when the car took over,” said Gordon Price, an urban planner and head of the cities program at Simon Fraser University in British Columbia. “People like these neighbourhoods for that very reason.”

Mr. Price suggested “things will settle down in the Plateau and the worst of what’s being predicted will not happen.”

Across the wider city, the neighbourhood is often portrayed as a haven for car-hating fanatics. The Plateau remains top-three among Montreal tourist draws, but across the metropolitan area it’s got a serious image problem.

We own a vehicle, as about half of the borough residents do, and like many drivers, we get annoyed by construction and confounding one-way street mazes engineered to calm residential streets. We own a parking spot, solving one problem, but my wife’s book club is reluctant to meet at our apartment; her fellow readers do not believe they’ll find parking.

“You can’t kill business by cutting 2,000 of the 60,000 parking spots in the Plateau, but you can kill businesses if you talk about these 2,000 bloody parking spots every day and keep saying ‘Oh my God, you cannot access the place,’” Mr. Ferrandez said.

The mayor of the Plateau is easily Montreal’s second-best known municipal politician behind city mayor Mr. Coderre, a political creature of the suburbs who is Mr. Ferrandez’s ideological and political opponent.

The rivalry between the two men has helped fuel the conflict. In one infamous episode this fall, Mr. Coderre overruled Mr. Ferrandez’s plan to rip out parking to put in a bike path near a park. Mr. Coderre declared Mr. Ferrandez was being “dogmatic” about the bike path; he kept the parking but had a 45-centimetre sidewalk built to widespread ridicule. “That hurt him,” Mr. Ferrandez says.

Outraged wheelchair users and a video sendup by a contemporary dancer – who used the narrow walkway as her stage – probably did produce a narrow public-relations win for Mr. Ferrandez. He can only hope convincing evidence emerges to turn such hollow victories into more substantiated wins.