Rarely does the opportunity to create a new street present itself in a densely built-out city like San Francisco. But neighbors and planners at the developing Mission Bay campus of the University of California, SF decided to make the best of such a chance by designing an extension of Fourth Street as a car-free plaza.

Fourth Street currently terminates at 16th Street just north of the Dogpatch neighborhood. The SF Board of Supervisors approved a plan [PDF] this week to extend it south to connect to Minnesota Street at Mariposa with a public plaza and bikeway. It will run between a parking lot and a building in a 289-bed hospital complex set to open in 2015.

“The plaza on Fourth Street will provide an opportunity to create a warm and welcoming civic space for all to enjoy,” said D10 Supervisor Malia Cohen at a June hearing of the Land Use and Economic Development Committee.

Residents in the Dogpatch neighborhood have been advocating for the creation of the plaza for years, said Susan Eslick, vice president of the Dogpatch Neighborhood Association. Aside from the benefits of creating a new public space, she said neighbors didn’t want to encourage motorists to use Fourth as a new through-way into the neighborhood. The plan “will keep Dogpatch the livable, small-scale neighborhood that it is,” said Eslick.

On the northern end, the plaza would connect to bike lanes striped on Fourth last year which end just before the Fourth Street Bridge. (There are no known plans for bike lanes on the remaining stretch of Fourth in SoMa, which runs one-way southbound north of Townsend Street.) Under the plan for the area around the plaza, 16th, Owens, and Third Streets will serve as the main routes for car traffic. The plaza will also be bookended by areas for car drop-offs and designed to allow emergency vehicle access.

Residents and advocates at the hearing praised UCSF’s extensive community outreach in planning the development over the last decade.

“We’re really excited about building out a street that doesn’t exist now,” said Andy Thornley, the (since retired) policy director of the SF Bicycle Coalition. “We’re about to build a really great street that’s really going to be a wonderful place as well — a great place to ride a bike, stroll, or just sit around and watch other people.”

“As someone else said at an earlier hearing, it’s going to be like Sunday Streets every day, and that’s a good thing,” he added.

Construction on the plaza is scheduled to begin in 2013.