Chinatown and North Beach, the “densest neighborhoods west of the Mississippi,” are set to be graced by Sunday Streets for the first time this year, Mayor Ed Lee announced today. City leaders and advocates said they’re eager for the opportunity to let residents experience Grant Avenue and California Street free of car traffic.

“Sunday Streets will be different from a street fair. It will allow residents to explore all uses of the streets,” said Mayor Lee. “This is about working with all of the elements of the community and breaking down bureaucratic walls to make things happen.”

The growing demand from neighborhood and merchants associations had initially put Sunday Streets on the horizon for next year, but a 2011 date is being chosen at the insistence of Mayor Lee, said Livable City Director Tom Radulovich.

Dwellers of the city’s urban core, including City Lights publisher and poet Lawrence Ferlinghetti, have long dreamed of pedestrianizing streets like the crowded Grant Avenue, he noted. Last year, a parklet made some headway by expanding the public realm in front of a Columbus Avenue restaurant. The area’s compact character will foster a slower, more pedestrian and play-focused environment than Sunday Streets held elsewhere, but it will not be like the vendor-oriented street fairs familiar to the area, said Radulovich.

“People living in Chinatown don’t have front porches or backyards to use,” said Supervisor David Chiu, highlighting the packed neighborhood’s long-stifled need for open public spaces. Sunday Streets will provide breathing room on the streets mostly reserved for storing and moving motor vehicles, despite the fact that it has one of the lowest car ownership rates in the country.

“It’s really great that there’s recognition that walking is the primary way of getting around Chinatown,” said Deland Chan, senior planner at the Chinatown Community Development Center. “We want to see the programming done in the most community-serving way, particularly for the elderly population.”

Advocates applauded the benefits Sunday Streets has brought to the city that go beyond encouraging healthy physical activity. Events in the past three years have provided an easy way for neighbors to meet one another and more intimately explore the streets around them when not subject to the impacts of car traffic.

“What greater way is there to connect neighborhoods and appreciate our city?” said Leah Shahum, executive director of the San Francisco Bicycle Coalition, who was excited at the opportunity to visit neighborhoods “not as a tourist, but as a local.”

Although the time frame is yet to be determined, SFMTA Sustainable Streets Director Bond Yee said the agency is working on squeezing the ninth Sunday Streets into the current calendar without conflicting with other events.

This year’s street parties will be held an hour later, from 11:00 am to 4:00 pm, to better accommodate church-going families, said Livable City Program Manager Susan King.

The first Sunday Streets of the season kicks off this weekend along the Embarcadero from Fisherman’s Wharf to Terry Francois Street: