A. Cars do not scale as a mode of local and regional transportation. This is an issue of geometry relating to road and parking space requirements, and will remain true even if gasoline-powered cars were replaced with electric cars. It is true that electric cars can dramatically reduce climate pollution from gasoline and diesel combustion and provide some local air quality benefits. However, cars also generate local air pollution from tire, brake, and road wear, and vehicle manufacturing (including batteries for electric cars) represents a considerable portion of lifecycle climate emissions and other environmental impacts. Being a very energy-intensive mode of transportation, electric cars necessitate large quantities of electricity generation, which inevitably has some environmental impacts even if renewable. Cars facilitate and encourage sprawling land use and design, which exacerbates climate pollution from buildings and material manufacturing and consumes large amounts of land. Finally, climate policies in wealthy countries should be designed to provide a template for other countries to follow, and “electrified sprawl” is simply not a scalable solution for 8-10 billion people.

A. Autonomous vehicles (AVs) have the potential to exacerbate street congestion through induced demand, as reduced labor costs, increased convenience, driverless pick-ups, and “deadheading” of empty vehicles all potentially contribute to an increase in vehicle miles travelled (VMT). We have seen this occur in many places with ride hailing services even at the higher costs required when drivers are present. The long history of failed attempts to reduce congestion by adding more road capacity, and recent experiments to test the magnitude of induced demand, underline the limits of this strategy. Moreover, the arrival date of autonomous vehicles has consistently been underestimated. It now appears that they won’t arrive for more than a decade. Given the limited time window for climate action, we need to apply technology available today, rather than just waiting for future technology to arrive. In the meantime we can develop policy to make sure that autonomous vehicles serve the values and principles laid out here.

A. Most academic studies suggest that even new market-rate housing targeted at high income households in gentrifying neighborhoods tends to reduce rents and displacement pressures in the aggregate. However, we believe that this question misses the deeper observation that our car-centric land use policies and exclusionary zoning are the root cause of the new displacement crises in urban areas. We believe that rolling back or eliminating exclusionary zoning is required to achieve equitable housing outcomes, and we believe that implementation should prioritize adding housing in wealthy, high-opportunity neighborhoods that currently exclude apartments. Much new urban housing is being funneled into sensitive communities experiencing displacement pressure because they have been historically zoned for higher density and because exclusive neighborhoods have been effective at blocking new housing. The vast areas currently zoned for single family homes only, that prohibit even small multifamily housing, provide broad opportunities to increase housing supply without going against the wishes of residents in sensitive communities.

A. Building new sprawl will lead to more traffic and total emissions of pollutants than building infill housing as more people are forced to commute via car. When people have to drive for all of the activities of daily life, this creates high traffic at a regional scale. However, we also believe that infill should prioritize approaches to reduce car-dependence so that traffic and pollution is alleviated especially where the most people are exposed to it. This can be accomplished through all the mechanisms described above, such as mixed use zoning, complete streets safe for all users, removing free or subsidized parking and road space for cars, and providing ample alternatives in the form of public and shared transportation modes.

A. We believe that this framing presents a false choice between urban housing and access to nature. Because so much of our urban land is reserved for cars and private yards, and because of the rise of modernist architecture and single-use zoning, people have become accustomed to austere urban spaces devoid of natural, pleasant, and human-scale elements. Traditional urban patterns and urban landscapes in many places around the world achieve much greater densities than typically found in the US while supporting publicly accessible natural areas and gardens. Moreover, the idea that low density housing provides access to nature and the outdoors has always been incomplete and inequitable, because it means that people who cannot afford large plots of land, who do not have access to cars, or who are unable to drive because of age or ability, are denied these amenities.

A. When we talk about the advantages of urban density, we are referring to the number of people or housing units per square mile of land area. This is related to but distinct from the question of crowding, which is a function of the number of people in an enclosed or restricted space, and implicated in viral transmission. Crowding is sometimes a desired feature of city recreational activities (such as a packed bar, concert, or open streets event), but often it is the result of insufficient and inequitably distributed built space. Less housing units per square mile in a place where many people want to live can often mean more people housed per room. Similarly, excessive allocation of outdoor space to cars can exacerbate crowding on sidewalks and in parks.

Public transportation ridership is down steeply during the pandemic, and transit operators face fiscal challenges even as they strive to implement new safety practices. We support fully funding public transportation to insure safe and adequate service especially for those who most need it. Transportation networks need a unified approach to transportation safety, including assessing and mitigating public health risks based on science, appropriately contextualizing relative risks of different transportation modes, and communicating these to the public. The Seamless Transit Principles developed for Bay Area transportation provide a template for reforming governance to support these goals. Bikeshare and other micromobility options-- equitably deployed and operating on complete streets-- can provide people with more alternatives and alleviate congestion both on roads and in transit. Dedicated bus lanes can allow more buses to run with greater efficacy and less crowding.

We can’t avoid a conversation about environmental justice when talking about impacts of the pandemic on cities. Our most vulnerable communities-- those which have been exposed disproportionately to pollution (itself a possible COVID-19 risk), have access to insufficient and inadequate housing, have been allocated insufficient public space, and have had insufficient access to health services-- are those which are seeing the worst impacts of the pandemic around the country. Even if there were an irreducible health risk of density over sprawl (which we do not believe to be the case), then exclusionary housing policies are no solution: they merely allow the privileged to opt out of these challenges, often while still enjoying the cultural and economic benefits of density.

Finally, urban density featuring flexible and diverse land use can enhance resilience to both pandemics and climate change. We don’t all have to live in skyscrapers, but living in environments dedicated to one housing type that require driving for all the activities of daily life are uniquely fragile, limiting both functional and economic responses to disturbance. If cities are urban ecosystems, then single-family detached zoning is urban monoculture. Natural environments do not all look the same, but they do share common features like diversity, modularity, and feedback that allow them to resist and adapt to stressors. We need to incorporate these principles into our human environments across spatial scales from small towns to towering metropolises.

Also see our March 2020 blog post led by Urban Environmentalist Robert Spragg.