From more than a block away, I hear the man playing the trumpet. It’s a little after 9 am Wednesday, and his classical sonata carries through the air nearly undisturbed, a remarkable feat given the player’s choice of corner. He stands at the usually cacophonous junction of Fremont and Market streets in downtown San Francisco, but today his sonic competition has been squelched.

Effective Wednesday, private cars have been banished from most of Market Street, the major thoroughfare that slices southwest through the heart of the city. Commercial vehicles and taxis remain welcome on most of the 2.2-mile no-car zone. Everyone else, Uber and Lyft drivers included, must find another way.

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On the first morning of the new era, Market is populated by buses, cyclists, and the occasional truck. Honking has been minimized, as everyone moves smoothly. Keeping the peace is a small army of transit workers, lining the route like so many parked e-scooters. A block from the trumpeter, the driver of a Nissan Sentra has found her way onto Market. A sentry in a fluorescent jacket and gloves steps in front of her car and commands she reverse, then turn onto a side street. Police on motorcycles swoop down on those who slip through the net, explaining the new rules and issuing warnings. Once the grace period ends, tickets will cost drivers up to $238, plus a point on their license. And debates arise: Mohammad Gulabzai had to argue with a cop for the right to tow his halal cart to its permitted place, between First and Fremont streets.

Commercial vehicles, taxis, bikes, and buses are all allowed on the major thoroughfare. Uber and Lyft drivers will have to find another route. Photograph: Lauryn Hill

The car-free regime looks to have pacified, but not depopulated, Market. Every day, half a million pedestrians and 75,000 transit riders make their way down the street. At peak times, Market hosts 200 buses and 650 cyclists an hour. The point of the project, which the city’s transit agency calls Better Market Street, is to help those people not just move efficiently and safely, but to “promenade and linger.”

Banning cars is less of an end goal than a prerequisite for other changes the agency plans, starting with “quick build” work. These cheap and easy changes include adding more than 100 loading zones on side streets for commercial vehicles and ride-hail passengers—Lyft’s app now blocks users from setting pickup spots on Market—and painted “safety zones” that give pedestrians more room at intersections.