It's often called the biggest transformation in how New Yorkers move in a half-century. From 2007 to 2013, under mayor Michael Bloomberg, transportation commissioner Janette Sadik-Khan oversaw the addition of hundreds of kilometres of bike lanes, hectares of new pedestrian plazas and concerted efforts to calm driving. Safety improved but vehicle congestion didn't spike. Now a principal at Bloomberg Associates, the consultancy set up by her boss when he left the mayoralty, she is part of a team that works to share the lessons they learned in New York.

Ms. Sadik-Khan came to Toronto this week in a visit hosted by the Metcalf Foundation, a philanthropic organization dedicated to sustainability and equity. She met privately with Mayor John Tory and spoke at an event co-headlined by chief planner Jennifer Keesmaat. Some takeaways from her remarks:

Cars don't shop, people do

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If the 20th century was the heyday of the car – though Ms. Sadik-Khan says it seemed more like a forced marriage than a love affair – 21st-century cities are recognizing that the goal is not simply moving vehicles as fast as possible. Think mobility of people, not movement of cars. And remember that taking space from cars – whether to offer safe routes for cyclists or to serve as plazas – can boost the fortunes of area businesses. After pedestrianization, Times Square became one of the 10 hottest retail areas in the world.

Change how road-space is allocated

Ms. Sadik-Khan noted that New York's transportation system wouldn't be able to absorb the number of people moving into the city. They needed a new approach, even if that meant less room for cars. As well as bike lanes, some bus routes were given dedicated space and traffic signal prioritization, sharply speeding them up and increasing reliability of service. While this inconvenienced some drivers, it made transit a more viable choice, and reflected the equity argument that it's unfair for a single person in a car to slow down dozens on public transit.

Try it out

"Paint is cheap" is the battle cry of the wave of urbanists inspired by the example of New York to try out different ways of using their streets. Ms. Sadik-Khan acknowledged that the Department of Transportation wouldn't have managed a fraction of the changes they did going through the traditionally laborious process of endless approvals. Instead, they moved fast, using paint, planters and cheap patio furniture to carve out space. It's a method that let officials test the results for real, instead of using computer modelling. If it worked, great; if not, it could be tweaked or reversed.

Data matter

Ms. Sadik-Khan was always keenly aware that her boss wanted to see the evidence, joking that then-mayor Mr. Bloomberg had "In God we trust, everyone else bring data" tattooed on his body. But when she started as transportation commissioner, the DOT had a lot of information that wasn't particularly useful. They added staff and ramped up the data, which helped make the case for change to residents and business owners. They could disarm skeptics with hard information and counter critics by pointing to the results of the pilot projects.

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It's not all Kumbaya

Perhaps the most striking slide in the presentation was of the before-and-after maps of New York's bike-lane network. But toggling quickly between one image and the other obscures the difficult, lengthy and contentious work behind the impressive transformation – one tabloid called a particular Brooklyn bike lane "the most contested piece of concrete outside the Gaza Strip."

So Ms. Sadik-Khan is quick to remind envious people in other cities that it was hard in New York as well. In a Nietzschean take on city-building, she warned that "when you push on the status quo, it pushes back at you." There was rancour and opposition and not everyone was satisfied. But she also said that when they showed what could be done, residents clamoured for similar changes in their neighbourhoods. By late in the administration, polling showed wide majority support for their work.