San Diego traffic engineers are asking the City Council to spend $22.5 million to widen the SR-56 freeway through Carmel Valley, less than three months after the city pledged to achieve carbon neutrality in the next 13 years.
The 2.2-mile expansion would generate roughly 12.8 million additional miles of car travel per year, according to an online calculator developed by researchers at UC Davis, representing a major setback in the city's quest to reduce driving and lower greenhouse gas emissions.
The project was advanced unanimously by a council committee on Oct. 12 and could be decided by the full council as soon as Nov. 1. Construction is scheduled for April and would last roughly two and a half years.
SR-56 is frequently congested during rush hour, and residents of the suburban-style communities that surround the freeway have long been asking for relief. The widening project, which has been planned since at least 2014, is the first of a three-phase plan to add connectors between SR-56 and northbound I-5.
Kristy Reeser, deputy director of the city's Sustainability and Mobility Department, said the project is consistent with the city's climate goals because the expansion would add carpool lanes, not general purpose lanes that can be used by any vehicle. She added the lanes could eventually be used by buses, and that a concurrent project would expand a bike path that runs parallel to the freeway.
"It really does support our goals in the (Climate Action Plan) for the transit mode share and making this area accessible to transit for more people," Reeser said.
Bus service along SR-56 is not currently planned until 2050. The bike path improvements are already funded and will be built regardless of whether the council agrees to fund the freeway expansion.
Construction of the new HOV lanes would be overseen by Caltrans, but it would be funded entirely by the city of San Diego using fees collected from developers who built projects in the area. It's uncommon for cities to fund freeway expansions on their own, said Allan Kosup, North County Corridor director for Caltrans.
At the council's Active Transportation and Infrastructure Committee this month, staff suggested the city's contribution would be capped at $22.5 million and Caltrans would absorb any cost overruns.
"I'm glad that we are capped at $22 million," said Councilmember Jen Campbell at the committee meeting. "I'm sure that would probably cover about a mile of this, so I'm glad Caltrans is coming through."
In reality, Kosup said, Caltrans will not be contributing any state funds to the widening. Design and engineering work was mostly funded by local and federal dollars, he said. If construction costs exceed $22.5 million — a real possibility given the high inflation rate — Caltrans would ask the city to contribute more.
"If they were unable to contribute more, we would reduce the scope of the project," Kosup said. "And we have those contingency plans in the back of our heads."
Despite the widespread desire for congestion relief on SR-56, the additional lanes will not provide it in the long term. This is because of the well-observed phenomenon of "induced demand." When freeway capacity is expanded, the short-term increase in vehicle speeds attracts new drivers and congestion returns within a few years.
City staffers acknowledged the reality of induced demand for general purpose lanes, but said the HOV lanes on SR-56 would not attract more drivers and instead encourage carpooling.
"The research is not on their side with that claim," said Amy Lee, a PhD candidate in transportation technology and policy at UC Davis.
Lee pointed to a study published last year by UC Berkeley researchers that found no significant difference between general purpose lanes and carpool or toll lanes when it comes to the amount of new driving they induce. Drivers who were already carpooling move over to the new lanes, and the capacity they leave behind is soon filled by new drivers. Researchers call this "lane filtering."
When asked whether drivers would see less congestion on SR-56 after the new lanes open, Phil Trom, program manager in the city's Sustainability and Mobility Department, said it was "hard to say."
In August, the City Council approved an update to San Diego's Climate Action Plan that sets a legally binding target of "net zero emissions" by 2035. That means all the city's carbon emissions would somehow have to be offset by removing the same amount of carbon from the atmosphere.
City staff have not yet provided a timeline or funding strategies for how they would accomplish the climate goals, but have promised to give more details by February.
One year ago, Mayor Todd Gloria told KPBS he would order a review of all planned road widenings in the city to determine whether they're consistent with his environmental and traffic safety goals. That review has not yet begun in earnest.
"What we've identified are a number of legacy projects that are working their way through the system that may envision stuff that made sense in the 1980s, 1990s or 2000s, but no longer make sense in the 2020s when we understand we have an urgent climate crisis," Gloria said last year. "As a general rule, I think widening roads is not the solution for climate action. … This does not mean you may not ever see them again, but my hope is that we'll do that on a much more limited basis."
Transportation, which accounts for more than half of the city's carbon footprint, is a major component of the new climate plan. By 2035, half of all trips across the entire city are to be made without a car. For those who would continue to drive, the city aims to shorten their trips by locating jobs and amenities closer to homes.
Corinna Contreras, policy advocate for the nonprofit Climate Action Campaign, said it was absurd for the city to claim the SR-56 expansion would reduce driving and greenhouse gas emissions when all the evidence suggests it will do the opposite. She added both the city and Caltrans are notably silent on just how much the new lanes would impact traffic.
"Is this going to relieve congestion by 17 seconds? Is it going to be 2 minutes?" Contreras said. "When we start asking those questions and we don’t get answers to them, it really is telling."
