Getting Over Our Highway Habit

Shifting Gears book cover by Susan HandyDriving between the Bay Area and Sacramento has long been a challenge. For the past several months, it has been a construction nightmare. Heading east from Davis, drivers face seventeen continuous miles of construction zones, first for the Yolo I-80 Pavement Rehab Project , then for the on-going “Fix50” project through the core of Sacramento. Heading west, the construction zone for the Solano I-80 Managed Lanes Project  starts before Vacaville and continues through Fairfield. I dread the day that construction starts between Davis and Vacaville, not just because construction makes for a miserable driving experience but also because it means the last remaining remnants of the iconic oleander median will be gone.

What does all this construction get us – and is it worth it?

The official rationale for these roads projects is the need to modernize old freeways (especially Highway 50) and accommodate the growing flow of traffic between Sacramento and the Bay Area driven by differentials in housing costs, the post-COVID ability to work remotely, and other economic forces. Congestion “relief” is cited as a goal of the projects in both official documents and statements by public officials. To relieve congestion, Caltrans is adding “managed lanes” to freeways, usable for free by carpools and electric vehicles with clean air vehicle decals and, in some cases, by other drivers for a fee.

This rationale does not entirely square with the state’s Climate Action Plan for Transportation Infrastructure (CAPTI). One principle of this plan is “promoting projects that do not significantly increase passenger vehicle travel.” As ITS-Davis researcher Jamey Volker and I have documented, a growing number of rigorous studies provide robust evidence that adding highway capacity generally leads to an increase in vehicle miles of travel (VMT), a phenomenon known as “induced travel.” Although the evidence on the effects of managed lanes is slim, there are good reasons to believe that these lanes may generate as much of an increase in VMT as the old-fashioned “general purpose” lanes. In short: adding lanes, even if they are managed lanes, is not consistent with state goals for reducing vehicle travel.

This can be a challenging idea to accept. For the past several years, Jamey and I have participated in countless Zoom meetings in which state, regional, and local officials have argued that highway widening projects within their jurisdictions would not lead to an increase in VMT or, at most, would result in a much smaller increase than studies suggest. After Caltrans official Jeannie Ward-Waller raised questions about the Yolo I-80 Pavement Rehab Project, which appears to be laying the groundwork, literally, for an additional lane, she was fired by the agency, as reported by the Los Angeles Times. Her concerns centered around potential abuses of the environmental review process, the purpose of which is to fully vet the likely impacts of proposed projects, including impacts on VMT.

Our own work has demonstrated how induced VMT has traditionally been underestimated or even ignored in the environmental review process. Agency forecasts of the VMT impacts of proposed highway projects are not especially good at capturing the various adjustments that drivers make when a new freeway lane opens. For example, deciding to drive to a more distant store, or making a trip that previously would have been too much of a hassle. By failing to account for these adjustments, forecasts tend to understate induced VMT which means that they understate environmental impacts and overstate congestion reduction. These biases undermine good decision making. Highway projects around the country are being challenged on this basis.

All of this controversy reflects something deeper and even more difficult to address than forecasting practices: an entrenched way of thinking that perpetuates the highway-widening treadmill that has dominated transportation planning for the last century, as I discuss in my new book, Shifting Gears: Toward a New Way of Thinking About Transportation.

One idea at the core of the traditional way of thinking about transportation is that congestion is bad, that it should be reduced, and that it can be reduced. No one likes congestion, but you’d think that, after a century of failed efforts to reduce it, we would have learned better by now. Congestion did abate temporarily during the COVID-19 pandemic, but not for reasons we would ever want to repeat. Rather than focusing on reducing congestion, we might be better off focusing on ways to make congestion less relevant to our lives. One way to do this is by providing good alternatives to driving, such as high-quality transit service. Another way to do this is by bringing the places we need to go closer to where we live. Rather than pouring billions into reducing congestion for workers who can’t afford to live near their jobs, why not pour billions into providing affordable housing for them near those jobs?

Another core idea that needs rethinking is that speed is good. Speed is psychologically complicated, in that it both thrills us and terrifies us. And terrify us it should: the faster that cars go, the more likely that their occupants—and bystanders—will die when cars crash. This trade-off is well documented and widely known but, too often in practice, speed takes precedence over safety. The transportation profession defines efficiency in terms of speed, and efficiency is something to be maximized. But just how much speed do we need? Isn’t this obsession with congestion really about our expectations about how fast we should be able to get places? Is it reasonable to measure traffic “delay” with respect to traffic-less “free flow” conditions? It would be a whole lot cheaper—and safer—to reset our expectations than to widen our freeways.

The power of these ideas might explain why the cost/benefit analyses that inform decisions about highway projects also fail to account for the costs that drivers incur during the construction itself. This failure suggests that such costs are accepted as a necessary part of providing congestion relief. But as a recent Sacramento Bee story poignantly documented, the human toll of highway construction can be intolerably high. Following the publication of the article, in which I was quoted, I received a heart-breaking email from a mother who her lost her daughter last year to a crash in the Fix50 construction zone.

We owe it to ourselves to reject a way of thinking that prioritizes congestion reduction and puts speed ahead of safety. It is high time for a new way of thinking about transportation.


Susan Handy is  the Director of the National Center for Sustainable Transportation at UC Davis. Her research focuses on the relationships between transportation and land use, particularly the impact of land use on travel behavior, and on strategies for reducing automobile dependence.

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