Aspirational plans by Mountain View City Council members to allow up to 10,000 new housing units in North Bayshore may hit a snag, after an early traffic analysis by the city shows that injecting that much housing into the office-heavy area would bring traffic to a standstill.
Early last year, council members agreed to revise the North Bayshore Precise Plan to include housing. Adding a residential neighborhood to North Bayshore, an office park primarily owned and occupied by Google, is part of a larger strategy to boost residential growth in the city. Although the number has fluctuated since Jan. 2015, the current goal is to add up to 9,850 housing units in the area.
But the big concern at the Sept. 27 City Council study session was whether the roadways into North Bayshore -- Shoreline Boulevard, Rengstorff Avenue and San Antonio Road -- could handle the kind of traffic generated by so many new residents. A preliminary traffic analysis indicated that vehicle trips associated with adding 9,850 units would far exceed the roadway capacity, and would fall well short of being compliant with the California Environmental Quality Act (CEQA).
The three roads have a combined "gateway" capacity of 8,100 vehicle trips during the morning commute into North Bayshore, and 7,940 during the evening commute out of the area.
Depending on the size of the units and the amount of parking allowed, 9,850 units could increase morning commute traffic, currently estimated at about 6,640 morning trips, by between 44 percent and 81 percent. For the evening commute, currently at 6,250 trips, that increase is even higher -- between a 81 and 99 percent increase in vehicles traveling in and out of North Bayshore.
The report estimates that between 1,300 and 3,200 units could be added to North Bayshore before reaching gateway capacity -- well below what council members were hoping to add.
"These results came in at a far different place than we originally anticipated," said Community Development Director Randy Tsuda. "It's pointing to the complexities of really trying to pull off a transition of this magnitude."
City Manager Dan Rich told council members the traffic study should be seen as an "early heads-up" based on the current data, and that city staff members fully intend to explore a range of options and policy tools to achieve the council's goals for North Bayshore.
"We don't think 3,000 (units) is going be the final number, but we can't tell you today with a straight face that 10,000 will be the final number either," he said. "It needs to be based off data and analysis."
Throughout the Tuesday study session, council members picked and prodded at the analysis, questioning whether the assumptions may have overestimated the effect of residential development on traffic. One of the big sticking points was that the traffic study lumped both inbound and outbound vehicle trips together to determine "gateway capacity," and that the big increase in morning commute traffic, for example, is really attributable to people traveling out of North Bayshore, not entering it.
It goes without saying that adding 9,850 units -- a 20-fold increase in the population of North Bayshore -- is going to increase traffic along the major access roads. But some council members were perplexed by the idea that residents leaving North Bayshore in the counter-commute direction would make a big difference in traffic flows into the office-heavy area.
Council member Lenny Siegel said he found it hard to believe that outbound traffic in the morning is going to bump up against the limit for gateway capacity when it's only one-sixth the number of cars heading into North Bayshore. Although staff suggested that drivers leaving North Bayshore will inevitably cause delays for the employees traveling into the area, Siegel pointed out that most people heading southbound are going to be headed straight, and likely won't be blocking any intersections until they hit Middlefield Road.
Siegel, along with Mayor Pat Showalter, also questioned whether the analysis low-balled the number of people who will both work and live in North Bayshore, making their commute "internal" to North Bayshore. City estimates predicted that between 10 and 20 percent of people living in North Bayshore will also work in the area. Siegel said he believes that number should be closer to 75 percent.
"The key variable in the analysis is the internalization rate, and I think the assumption that you're making is way off base," he said. "This is not Mission Bay, this is North Bayshore. It's clear that people are willing to pay a premium to live near the workplace."
City staff were quick to clarify that the traffic analysis doesn't preclude building more than 3,200 units of housing in North Bayshore, but another traffic analysis will ultimately determine what kind of residential development will be allowed, given the constraints of the roadway infrastructure into the area.
"This is likely how the analysis will have to be put together to be CEQA compliant," Tsuda said. "You can't put your aspirational goals into the CEQA analysis, they are, by their very nature, conservative."