Presidio Boulevard. Photo: Michael Rhodes

In an effort to make the Presidio function less like a traffic shortcut and more like a national park, the Presidio Trust is trying out an idea that’s caught on in the dense city that borders it: a trial street closure. From today until October 27, Presidio Boulevard will be closed to private automobiles between West Pacific Avenue and Upper Simonds Loop [map PDF], as the Presidio Trust and the MTA study traffic impacts. Muni and emergency vehicles will still have full access.

Traffic on Presidio Boulevard is about 60 percent cut-through, compared to 50 percent in the park as a whole. When the Doyle Drive replacement project is completed in 2013, that volume could go even higher, since the newly constructed Presidio Parkway will have a new interchange that will make Presidio Boulevard an attractive approach route for drivers.

The Presidio Trust wants to experiment with road closures that will train drivers not to use routes through the park once Presidio Parkway – the Doyle Drive replacement – opens. Planners are rushing to study the traffic impacts under regular circumstances since construction will begin later this year, altering the area’s normal traffic patterns.

Over half of Presidio Bouulevard’s traffic is cut-through. Photo: Michael Rhodes

About 35,000 automobiles use the park’s roads every day, half of it cut-through. That figure does not include traffic on the two highways through the park, CA-1 (Park Presidio Boulevard) and US-101 (Doyle Drive), which is almost entirely cut-through.

"We feel like, as a national park, we really need to prioritize our park users over folks who are just using us as a cut-through and maybe going a little faster than they should," said Presidio Trust spokesperson Dana Polk. While CA-1 and US-101 bring considerable noise and emissions to the park, their grade separation makes them less of an immediate safety threat to park users, she said.

"Our concern is, we’re putting in a lot of new trails, and we’re getting more and more recreational use," said Polk. "We really want to maintain the level of safety we have now for bikers and walkers, runners, hikers, and also just discourage people from using the national park as a shortcut." A majority of that shortcut traffic uses Presidio Boulevard, she said.

Some of the Presidio’s 3,500 tenants are concerned about the mobility impact the road closure will have. The Presidio Trust is considering adding a shopping shuttle to Laurel Village, and is looking at making immediate upgrades to the trails in the east side of the park, many of which are unpaved and unsuitable for bikes or strollers. "There were some people who live on this side of the park who could walk to the Julius Kahn playground but haven’t done so because they feel the trails would be hard to maneuver with a stroller," said Polk. "We’d want to do it right away so people could have that option during the study period."

CA-1, shown here passing next to Mountain Lake Park. CA-1 and US-101 will remain open during the traffic calming trial. Photo: Michael Rhodes

Unlike the city’s Pavement to Parks trial plazas, there are no plans for an extension if the trial succeeds. There has been discussion, however, of a Sunday Streets style event during the closure, if it can be organized in time. Similar to the temporary plaza in North Beach, it could provide an opportunity to make the most of a space freed-up for other reasons.

While the traffic experiments on Market Street are the big car-free news today, it’s worth keeping on eye on the Presidio, a national park where pedestrians and bicyclists ought to be able to find respite, but often find themselves in more conflict with cars than they do on some of the city’s most unreformed traffic sewers.