But even traffic experts haven't yet quantified how much worse that commute would become if local jurisdictions approve two major nearby development projects. Suffice it to say that steering wheel covers might have to be replaced a lot more often if unrelated proposals for a 1 million-square-foot development project in Menlo Park, and a mini-city on the Bay in Redwood City, come to fruition.
"There are only so many ways to get to 101," Menlo Park Mayor Rich Cline said in an interview. "I don't know how to solve that, that's the thing. (Traffic) is a huge impact, it's probably unmitigatable in a lot of ways. It's a chief concern, without question."
Marsh Road is only one of several streets in Menlo Park and Atherton that could be affected by those proposals, and by a planned expansion of the Stanford Medical Center. But it can perhaps serve as a case study to illustrate how these projects could impact already overburdened thoroughfares.
According to the city of Menlo Park, Marsh Road was designed to bear about 20,000 vehicle trips per day. The segment of the road just west of the freeway onramp currently sees about 34,000 cars per day.
According to a consultant, the Menlo Gateway project proposed by developer David Bohannon, near the intersection of Marsh and Bayfront Expressway, would add about 2,500 daily trips to the total.
But that amount might be miniscule when compared to the number of trips generated by the Redwood City Saltworks project, a development nearly the size of Menlo Park proposed by agribusiness giant Cargill, stretching along the Bay between Woodside Road and Marsh Road. A Jan. 26 report on that project estimates that it would put 2,600 to 3,100 cars on Marsh Road during peak morning and afternoon commute hours alone. Peak-hour trips represent only one-fifth of the total daily trips the project is expected to generate.
At this point, it's difficult to get a complete picture of how the Cargill project would affect local streets, as an environmental impact report has not yet been released.
"Clearly, there will be additional trips on Marsh Road and on Bayfront Expressway, but at what level is difficult to tell," said Chip Taylor, who heads Menlo Park's transportation department.
And there are a number of caveats that concerned commuters should take into account. The preliminary estimate of traffic from the Cargill project reflects the number of vehicles that would use sections of Marsh Road both west and east of U.S. 101, while the city estimates given above pertain only to the section immediately west of the highway.
The consultant's report also doesn't take into account the fact that people who already use the thoroughfare might move to the new development, meaning that the report might be counting some trips twice. In general, the report notes that the project might help to alleviate the Peninsula's jobs-to-housing imbalance, actually reducing the vehicle miles traveled per household.
The estimates related to the Bohannon project don't reflect the fact that Menlo Park is pressing the developer to more aggressively encourage people to take public transportation. And it's possible that neither project will be built for decades, if at all.
Still, the Cargill project in particular — and the 25,000 new residents it would bring — would undoubtedly mean more traffic on local streets, including Woodside Road, Bay Road, Middlefield Road, and El Camino Real. Pair that with the effects of a major Stanford Medical Center expansion on Sand Hill Road proposed in Palo Alto, and Menlo Park and Atherton officials may find themselves wincing when they ponder future traffic patterns in their cities, with state law and the beneficence of other jurisdictions their only recourse.
Mr. Cline, the Menlo Park mayor, said he was looking forward to hearing what Redwood City council members had to say about the Cargill project in a Feb. 1 study session. Noting that the consultant's report identified no insurmountable obstacles to the project proceeding through the approval process, he said:
"Unmitigatable traffic can be viewed as an impassable obstacle. If they can't fix that, it's going to deteriorate the quality of life, home values ... these are significant impacts that we have to be aware of."