Stockton Street’s car-free Christmas — and beyond?

Food vendors, entertainers and puppies will once again replace jackhammers and wooden walls as one of San Francisco’s newest holiday traditions transforms two blocks of Stockton Street from a cacophonous construction zone into a pop-up pedestrian plaza.

The gathering spot, which opens Friday, is a side effect of the city’s massive Central Subway project beneath the street.

[...] whether the shopper-friendly plaza will stick around after the subway tunnel is completed — or be turned back over to traffic — remains unsettled.

On Monday, the rumbling of heavy equipment drowned out the holiday music and jangling bells as crews hustled to finish up work on what is known as Winter Walk SF.

Workers tamped down asphalt and rolled out yards of fake green grass, planting wires in it for temporary street lamps covered in holiday lights and wreaths in time for the busiest shopping period of the year.

The project makes the streets too narrow for the throngs of shoppers, so this is the third year that the Municipal Transportation Agency has cooperated with Union Square merchants to turn the site into a makeshift holiday haven.

The pop-up plaza has proved so popular among shoppers and store owners that the city started working last summer on plans to keep the two blocks of Stockton Street closed permanently — a potentially profound downtown shift in a city often obsessed with traffic.

While his wife shopped, 58-year-old Monterey resident Harold Lehon watched as his 2-year-old son pushed toy cars on the edge of the still-blocked-off turf.

Many Union Square retailers find the prospect of a year-round pedestrian plaza alluring, said Karin Flood, executive director of the Union Square Business Improvement District.

“Studies show that if you have a welcoming pedestrian area, it increases foot traffic, which could translate to better retail sales,” she said.

[...] some other businesses — particularly hotels — fear that keeping Stockton Street closed will exacerbate the difficulty of the already challenging task of navigating a vehicle around the Union Square area.

Before her death in September, Chinatown leader and political power broker Rose Pak called the plan for a permanent walking mall “unacceptable” in a letter to MTA director Ed Reiskin and vowed to ensure its defeat.

Supervisor Aaron Peskin, whose district includes Chinatown and Union Square, said he’s still studying the issue, and noted the opposition in Chinatown, a mixed reaction in Union Square and the impacts on traffic.

MTA spokesman Paul Rose said the agency is preparing different scenarios for Stockton Street but hasn’t made a decision yet — and won’t “without consulting neighborhoods along the route, including Chinatown.”