"It's a major commute route," said Barry Burr, a member of the city's pedestrian advisory committee, which studied traffic volume on the trail last year.
The four-mile walking and bike path connects several neighborhoods with thousands of jobs in the Shoreline district, prompting the Association of Bay Area Governments to call it "one of the best-developed and most ambitious trails in the Bay Area."
But the city is working to make it even better. In the spring, a tunnel under El Camino Real will be complete, allowing a 1.6-mile trail extension into yet another neighborhood, Waverly Park, at Sleeper Avenue.
City manager Kevin Duggan believes few other cities have taken advantage of potential trail corridors the way Mountain View has.
"It's been amazing, because 20 years ago there really weren't any trails like this in town," he said.
This Tuesday, Dec. 11, the City Council is scheduled to make a decision that could move another major trail forward — the Permanente Creek Trail. If council approves, city staff will study an undercrossing at Old Middlefield Way, which could result in the trail's extension a mile south of Highway 101.
Meanwhile, on the east side of town, preliminary plans are in place to extend the Hetch Hetchy Trail through the entire city on a 3.5-mile east-west stretch. The existing half-mile Hetch Hetchy Trail runs from Whisman Road to the Stevens Creek Trail.
Ultimately, city officials hope the urban trails will create a network of routes over car-jammed freeways, under busy streets and through open spaces. There are numerous obstacles, however, such as opposition from neighbors, and physical obstacles such as housing developments that use the Hetch Hetchy right-of-way for parking.
"Great things take time," said Bob Kagiyama, the city's principal civil engineer.
Two Permanente crossings
Besides the undercrossing at Old Middlefield Way, the Permanente Creek Trail extension requires a good overcrossing at Highway 101, which would connect the trail to residential areas west of Shoreline Boulevard. The 101 crossing is a top priority for the bicycle and pedestrian advisory committee.
Currently, walkers and bikers cross Highway 101 at the Shoreline Boulevard overpass, but that crossing "is very limited as far as safe crossing goes," said Burr, a regular bike commuter. "Permanente Creek will give us that quick access. That whole area is going to continue developing. It's going to be even more important to have Permanente come through."
The Permanente Creek Trail's northernmost trailhead is just west of the Shoreline Amphitheatre. It then runs south, squeezing between Google headquarters and the former Alza building before it dead-ends at the northern edge of Highway 101, near another Google building.
If the council approves, this is where a pedestrian overcrossing will begin a gradual climb over Highway 101. The council has put the crossing on hold until the rest of the trail is clearly feasible.
On the southern side of Highway 101, another obstacle stands in the way: a section of Old Middlefield Way where cars speed on and off Highway 101. The City Council toured the area recently, and member Nick Galiotto said an at-grade crossing would be one of the "most dangerous things" he's ever seen.
Trail advocates are also waiting on the Santa Clara Valley Water District to present its plans for flood protection along Permanente Creek, which should include plans for the one-mile trail extension, which the water district would build, Kagiyama said.
Kagiyama said the district has determined that Permanente Creek Trail will have to end farther south at Middlefield Road, because numerous plots of private property stand in the way. Bicyclists will be able to continue southward on Farley Street, however, where eventually they may be able to connect to an extended Hetch Hetchy Trail near Central Expressway.
The Hetch Hetchy challenge
The Hetch Hetchy right-of-way is owned by the San Francisco Public Utilities Commission and runs east-west through the city for 3.57 miles, along the path of the Hetch Hetchy aqueduct. To make servicing the massive underground aqueduct possible, no buildings may be built on top of it.
At the existing trail terminus, the aqueduct can be seen meandering away until it vanishes to the west under Highway 85. It then resurfaces under a residential parking lot, crosses the intersection of Moffett Boulevard and West Middlefield Road, overtakes a strip of open space, crosses the intersection of Montecito and Shoreline Boulevard, hits a driveway and parking lot, more open space, Central Expressway, Rengstorff Park and, finally, San Antonio Shopping Center.
Because of all those various uses, pushing a trail through may be a long-term goal at best, said council member Ronit Bryant.
"It would be fabulous to have something going east-west," she said. "But there are all kinds of problems with it. The Hetch Hetchy right-of-way is completely paved over" in some areas.
"It's not all that likely we will be able to connect all the various segments," she concluded, but added, "We have it in the open space plan to try to do whatever we can to have another trail going east-west."
Council member Matt Pear noted that for every person who supports the trails there is a neighbor who opposes them due to fear of crime, noise or loss of privacy. He said there have been a few bad incidents on the Stevens Creek Trail, and that one man used it to escape from a robbery by motorcycle.
As for the parks and recreation commission, project manager Helen Kim said trail plans are still being evaluated.
Despite the obstacles and potential problems, "The trails are a wonderful way to connect neighborhoods," Bryant said. "You find yourself being cut off from people. When you have a trail connection you just walk over."