It might sound counterintuitive, but, while traffic congestion might decrease in the short term, widening actually creates more traffic congestion over time.

Why? Decades of research from past widenings show that, as drivers see extra capacity, they make more trips, they shift trips from other times of day, and they decide to drive instead of take transit until congestion is right back to where it started. Cars take up a lot of space, so even just a small increase in the number of cars on the road is enough to exponentially increase congestion.

The added driving doesn't only congest the freeway. They congest our local streets and local South San Francisco, San Bruno, Brisbane, Daly City, and San Francisco communities.

In fact, Caltrans' induced travel calculator cited in their own traffic analysis framework estimates that increasing vehicle capacity by 25% along the 9.4 miles of US-101 between I-380 and San Francisco County would induce additional driving by 400,000 miles of additional driving every day, the equivalent of an additional 16,000 cars clogging San Mateo County, San Francisco County, and Bay Area roads every day.

Our tax dollars deserve to be spent on projects that actually fix traffic, not make it worse.

Funding large transportation projects is complex. Regional, state, and federal dollars rely on price matching programs, meaning San Mateo and San Francisco Counties will be on the hook for millions.

Moreover, most transportation dollars are flexible and can be used for other things that actually fix traffic, like fixing potholes, supporting transit service, and increasing walking and bicycling networks. For example, the nearly $600 million US-101 widening project from Redwood City to San Bruno largely used voter-approved SB 1 funds, which promised to fix roads and improve transit but instead went toward taxpayers footing the bill for more traffic.

Ultimately, widening freeways is a policy choice. San Mateo County, San Francisco County, and Caltrans officials can instead choose to not widen the freeway, saving the county money.

Put simply, widening freeways is fiscally irresponsible.

San Bruno, South San Francisco, Daly City, and the southern portion of San Francisco surrounding US-101 represent the highest concentration of low-income communities of color in San Mateo and San Francisco Counties. That isn't a mistake; centuries of oppression and racist decision making mean that many people have no choice but to live near the freeway. Downtown South San Francisco adjacent to US-101, for example, is in the 96th percentile of most polluted census tracts in the entire state of California. 

Because widening freeways attracts more people to drive, that means our communities near the freeway suffer:

• More health issues from pollution and particulate matter from burning fossil fuels and wearing tires.

• More greenhouse gas emissions that contribute to sea level rise, wildfires, bad air quality, and extreme climates.

• More noise from automobiles.

• More unsafe roads from added traffic trying to get on and off the freeway.

Our communities deserve better.

Transit helps reduce congestion and take cars off the road. Making driving easier makes transit less attractive. When officials propose to widen US-101, they're actually saying they want to divert funding and ridership from public transit.

Why? As more people choose to drive instead of take transit, they won't ride Caltrain, which is parallel to the US-101 and already has the lowest pandemic ridership recovery in the Bay Area, or SamTrans, congesting local roads for both people driving and people taking transit. We've already seen that when officials widened US-101 in 2023, Caltrain's ridership struggled to keep pace with the increase in driving.

Moreover, officials are already starving transit. A recent study found that San Mateo County currently spends a whopping 88% of its state transportation funding on projects that increase driving or make no dent in decreasing driving (compared to 80% of all state transportation funding), and only 12% of its state transportation funding on transit and other projects that reduce driving. So when San Mateo County officials tell you that they will also increase transit, they're really trying to tell you they're funding the scraps for transit.

We can do better.

It's no secret that driving takes up a lot of space and energy, releasing emissions and pollution into our environment that are bad for our communities and our future.

But that fact isn't always intuitive. The biggest impact from transportation is not how many cars are carpools or how long vehicles idle, but how much vehicles drive. Driving increases greenhouse gas emissions and particulate matter (and even fully electric vehicles have large environmental impacts in the form of break dust and tire wear). Because US-101 is one of the main throughways in San Mateo County, a 25% increase in vehicle capacity will dramatically harm the environment.

Officials' assumptions are flawed, too, because they assume that everyone will drive. The environmental report of the US-101 widening from Redwood City to San Bruno, for example, claimed that there would be no environmental impact on traffic because everyone will drive anyway. When officials start with the assumption that everyone will drive, then there's no more room to increase driving. But if officials were to start with the assumption that people will take the most efficient choice for their needs given their options, then we can start to change the narrative.

Our future depends on solutions that reduce emissions and pollution from cars on trucks, not increase emissions and pollution.

People don't just want reduced congestion, they want more options and freedom of mobility. 

We currently live in a county and state where most people are forced to drive for most trips. But, as San Mateo County adds more jobs and housing, there simply is not enough space for every person to drive.

It doesn't have to be that way.

People want to be able to hop on a bus or train so they can relax on the way to work; they want to take their bike or walk to nearby destinations without congestion; and they want to be able to take a car if they need to carry things.

And that's great! When some people take more trips on transit, walk, or bike, it frees up space for those who need to drive. But we need to be able to let people have that freedom, and that means not widening US-101.

There are no laws that prevent Caltrans and San Mateo County from converting a lane to a managed lane. There are no funding regulations that prevent Caltrans and San Mateo County from converting a lane to a managed lane. In fact, SB 922 (2022), authored by San Francisco's and San Mateo County's own Senator Scott Wiener, reduces barriers to converting a general purpose lane to a managed lane by eliminating bureaucratic environmental regulations that increase the cost of encouraging transit, walking, and bicycling. Thus, the only opposition to converting lanes to managed lanes is political, not legal.

Converting lanes to carpool lanes or Express Lanes, as opposed to adding general lanes or auxiliary lanes, would help achieve Caltrans' and San Mateo County's project goals of reducing congestion--without adding more traffic. In fact, San Francisco converted lanes of US-101 to a transit-only lane to build Van Ness Bus Rapid Transit and a converted a lane of SR-1 to a carpool / bus lane on Park Presidio, Crossover Drive, and Lombard Street. Since the conversion of US-101 to Van Ness Bus Rapid Transit, Muni transit has seen faster and more reliable travel times and ridership 31% higher than pre-pandemic levels, without increasing congestion.