Most of Paris was asleep when a team of men in orange overalls fanned out across an avenue in the 11th arrondissement with blowtorches and road paint. They labored for hours to show Parisians a radical new way to use their 400-year-old street. By daybreak, one lane of regular traffic was gone and the asphalt was lined with rows of freshly stenciled yellow bicycles.

Squads like this one have been dispatched almost nightly across the City of Light since France first lifted its coronavirus lockdown on May 11. By order of the mayor, they are claiming territory from cars and giving it to commuters avoiding public transit. The plan is to give citizens more than 400 miles of pop-up bike lanes throughout Greater Paris that didn’t exist before the pandemic.

“The fact that in the space of a few weeks we’re quite radically changing public space to take room away from cars and give it to bikes is quite stunning,” said Christophe Najdovski, the deputy mayor of Paris for transportation and public spaces.

Normally it would be impossible to move so quickly given the controversy often generated by new bike lanes, which opponents argue take away space for car parking, cause more congestion for drivers and present a safety hazard for pedestrians.

But cities in the world’s hardest-hit countries, from Oakland to Milan to Mexico City, realized all at once that coronavirus lockdowns had opened a window, unique in the postwar era, for urban cycling to gain new ground.