This summer’s series of extreme wildfires, hurricanes, and tropical storms have made it more apparent than ever that the effects of climate change are here.
Limiting the damage caused by future disasters will require a whole-of-government approach — one not limited to what the federal government can do. There’s a host of ideas that states and municipalities could implement to curb greenhouse gas emissions, particularly in some of the world’s biggest polluters: American cities.
According to a 2021 study published in Frontiers, Houston, Chicago, and Los Angeles have some of the highest per-capita emissions totals in the world. The study broke down cities’ emissions based on sector, using the most recently available data (from 2009 and 2010), and found a large portion of those emissions come from transportation.
Data from the EPA shows that the transportation sector is actually the biggest source of pollution in the US, and that light-duty vehicles (or passenger cars) are responsible for 58 percent of those emissions. Overall, the EPA’s research — and the 2021 study — reinforce the fact that the transportation systems of American cities over-rely on cars in ways that are not sustainable should the US actually want to approach its stated greenhouse gas reduction goal of 50 percent by 2030, a number it has to reach in order to limit global warming by 1.5 degrees Celsius or less.
Reducing driving is difficult, however, because American cities, particularly those across the Southwest, are built for drivers. Biking and walking are often not options, and public transit, where it exists, does not typically serve trips that do not involve going from a city’s outskirts to its downtown or back.
“There’s really only one rational way to get where you’re going, and it’s typically not direct,” said Jeff Speck, a city planner and the author of Walkable City. “It’s typically organized around the assumption of driving as the only viable transportation mode.”
The greenhouse gases produced by this reality are not inevitable. They’re underwritten by federal, state, and local policy, from the initial construction of the interstate highway system to the recent bipartisan infrastructure bill, where the $39 billion in new funding for public transit is dwarfed by $110 billion for improving, expanding, and building new highways, bridges, and roads.
Transforming American cities to be more walkable isn’t easy, but there are measures local authorities can take to create a safer, more democratized transportation ecosystem that can positively affect the climate crisis. I spoke with several urban planners, transportation scholars, and advocates to learn about the most important strategies for curbing car reliance in cities. From those conversations arose the following solutions — all of which are implementable on the municipal level.
Make streets safer for bikes and pedestrians
Many of the car trips that people take are within biking distance — say, to dinner, or an activity like a movie theater. But people may choose to drive because riding would be dangerous. They might have to cross a highway or bike down roads where there are no bike lanes.
Places where bike ownership thrives — which can be as big as a city like Amsterdam, which has such a widespread bike network that cycling is favored over driving, or just a college campus — have prioritized bike and pedestrian safety over cars.
In most American cities, particularly in the suburbs, that’s not the case. And when the efficient movement of cars is considered paramount over the safety of any other mode, accidents and fatalities occur. The car-centric transportation system is contributing to a consistent yearly uptick in pedestrian casualties; they rose 21 percent in 2020, according to the Governors Highway Safety Association (GHSA).
“The problem is, the minute you leave the local [road], you probably enter an environment in which it’s not safe to bike because the bike lanes aren’t separate,” Speck said.
By adding protected bike lines — separated from car lanes by a barrier for safety — biking becomes a safe, accessible alternative to shorter drives. Essentially, bike lanes have to be set apart by something other than “a scrap of paint,” said Ralph Buehler, the chair of Urban Affairs and Planning at Virginia Tech. This is something that became clear during the first year of the pandemic: the GHSA found that 2020’s uptick in pedestrian deaths came despite traffic decreasing by up to about 42 percent at the peak of the pandemic. Reducing traffic alone doesn’t make biking and walking safer; the streets themselves need to be redesigned with safety in mind.
This sort of redesign also incentivizes walking and biking. Speck’s research has found converting 12- to 14-foot-wide driving lanes into 10-foot-wide lanes slows average car speeds from 40 miles per hour to 25 miles per hour and creates room to either add bike lanes or street-side parallel parking, which better protects the sidewalk from traffic.
And relatively inexpensive changes like turning one-way streets into two-way streets or lowering the curb radius so that cars slow down more when they make right turns are also proven to reduce crashes and injuries, Speck said.
Studies conducted in cities that have made such changes have found marked decreases in car use. Oslo has redesigned its roads in high pedestrian traffic areas, such that 91 percent have speed limits under 40 miles per hour, while expanding its system of bike lanes. It saw a 77 percent increase in bike traffic between 2014 and 2020.
There are American examples too. In Philadelphia, an investment in miles of protected bike lanes led to a nearly 70 percent increase in the number of people who biked to work from 2010 to 2017, even as congestion and public transit use worsened.
Buehler added that for such changes to be successful, there also needs to be connectivity across areas. If you’re taking a shorter trip to pick up takeout or grab a few groceries, much of it may be bike- or pedestrian-friendly — except for a critical highway juncture. To promote walking and biking, cities need to ensure that routes exist for human-powered transportation to every place the average person needs to go.
When I lived in Madrid, I could walk or take transit practically everywhere without ever crossing a highway that had no pedestrian infrastructure. I would take 30-minute walks home in the middle of the night from clubs, when the Metro was not running. Even in the dark, there were no crossings where I was unprotected as a pedestrian.
Examples of similar connectivity can also be found in the US, Buehler said, most commonly with respect to schools.
“There’s a safe-route-to-school program that tries to design safe routes to school,” Buehler said. “You can also think about that to community centers. The main point is designing networks.”
Safe routes to school are a start, but to really promote biking and walking, cities need to develop safe routes to other places, like drugstores and restaurants, as well. There’s a very large obstacle to doing this at the moment, however: zoning.
End single-family zoning to encourage mixed-use development
On its face, single-family zoning is a housing policy that creates quiet, uncrowded neighborhoods by restricting the development of apartments, townhouses, or any other dwelling that’s not a freestanding home. It’s incredibly prevalent in the US (75 percent of residential land is single-family zoned), and, as my colleague Jerusalem Demsas points out, it is incredibly harmful. It has had a racist impact, having been used to exclude people of color from certain neighborhoods, and it overall increases the cost of housing by limiting supply.
Another problem with single-family zoning is that it encourages car usage: In areas zoned for single families, there can be little development; the idea is people live in one area and then access workplaces, leisure activities, and stores via car.
“We zoned and created bento boxes,” said Brian Jencek, the director of planning at HOK, a planning and design firm. “Never let the gravy and rice touch. … Now we want stew, but we have to undo over a century of American planning.”
The best way to make that stew is to create mixed-use development, which facilitates what Jencek calls the 20-minute city, meaning you’re never more than a 20-minute walk from everything you might need, from jobs and schools to pharmacies and clinics to community centers and parks. In a mixed-use city, that’s possible. But in most American suburbs, single-family zoning does not allow for it.
Going back to my Madrid example, mixed-use development meant that nearly everything was within walking distance. From my neighborhood, I could walk to school, stop at a bakery along the way, get any beauty services at a salon on the way home, and meet my friends for dinner at night. I walked or took public transit everywhere.
Compare that to my grandparents’ house, in West Bloomfield, Michigan, a suburb of Detroit. Due to single-family zoning, the only activity we can walk to is to see my cousins who also live in the suburb. Any restaurant, appointment, or shopping has to be a car trip.
Razing West Bloomfield and rebuilding it as a 20-minute city isn’t really feasible. But one change that could encourage the development of walkable cities over time, Speck said, is eliminating single-family zoning in areas that are within walking distance of transit stops. Doing so would encourage the development of commercial spaces, which would benefit residents in the area; and those not living near the new services would be able to access them via public transit, lessening the need for a car.
Upzoning near transit also means that homeowners could add accessory dwelling units, or granny flats — a detached housing unit — on a lot, Speck said, helping to situate middle- and low-income people near transit, easing the housing crisis and putting more people in walkable and transit-accessible communities.
While increased development is often associated with rising property values and gentrification, Jencek said mixed-use development, done with community input, can create the economic benefits of development without pricing people out. The end result of rezoning would look different in different neighborhoods but does not necessarily mean a complete overhaul of a community. It could just mean adding a one-acre community park to a neighborhood without recreation access or creating a network of safer, slower streets to invite restaurants to expand their outdoor seating.
The idea is simple: Add a new land use to a neighborhood, creating an activity or business site that is accessible without a car.
Make drivers pay the costs of driving
The first two solutions focused on making driving less necessary. But people don’t always drive because they need to — they often do so because it is convenient and cheap.
It’s true that the upfront cost of a car is high, and there is gas and insurance. But drivers’ other costs — road maintenance, traffic lights, and policing, for instance — are heavily subsidized. Speck said estimates place the subsidization of driving at $10 for every dollar a driver spends as opposed to $1.50 for public transit.
Much of that subsidization comes in the form of taxes, which people pay whether they drive or not, but there are a lot of indirect costs as well: In higher-income households, people use highways but do not have to pay for the noise and emissions in the low-income neighborhoods that highways run through, for example. And the climate costs of mass driving affect everyone, regardless of car ownership.
One solution to this is congestion pricing, where drivers must pay a fee to drive in high-traffic areas or during peak hours. Central London imposes congestion pricing, and New York City has plans to do so, though they may not materialize. Another idea is to increase the gas tax, so that actual drivers are paying the costs of car infrastructure rather than general taxation. Both of these price controls could disincentivize driving.
But many experts believe making driving less convenient would do more to limit car usage, and one easy way to do this is to reduce the supply of parking.
Every mode of transportation needs a terminal. Planes have airports and boats have seaports, both of which require travelers and companies to pay. But for cars, parking “is capitalized into the costs of the goods you buy,” Brian Taylor, the director of the Institute of Transportation Studies at the University of California, Los Angeles, said. Think about your local grocery store — the parking lot is often larger than the actual commercial space, and it’s free. The grocery store is expected to pay for the parking lot through the revenue it generates from sales.
“We treat that as sacrosanct,” Taylor said. “The default is that the storage of private vehicles tends to get priority if you look at how we’ve allocated curb space. And that creates all sorts of problems.”
Delivery vehicles and rideshares that need to pull up on the curb have no space, so they halt traffic. Traffic is generated by people circling and looking for parking, knowing they can park on the street for free instead of paying for a garage. And because city governments mandate parking requirements for most types of development, commercial development — and therefore connectivity — is stunted by the need for parking.
Most American cities require parking minimums, meaning new apartment buildings and developments have to cordon off a certain amount of space for people to leave their car, either for free or for a rate much lower than the market price, considering how valuable that space is.
If cities removed their minimum parking requirements for developers, there would be far less incentive to provide free parking. A private developer would likely still build some off-street parking — but they would charge for it.
In Los Angeles, for example, Taylor said the real cost of an underground parking space might be $60,000. So a condo that costs $520,000, and comes with two underground parking spaces, could instead be sold at $360,000, with owners offering parking at its real cost of $60,000 per space. In that scenario, a family might forgo a second car and get an electric bike instead.
To disincentivize street parking, Taylor suggested municipalities raise the price at meters, manage curbs differently, or remove parking altogether in some areas and only allow loading, unloading, and scooter and bike traffic.
These are all strategies that would need to be rolled out in tandem with expanding connectivity, particularly with public transit. It is easy to imagine a situation in which gas taxes and expensive meters begin to primarily hurt low-income communities with zero access to public transportation, for instance. But once other options are in place, imposing the costs of parking on drivers would make driving more like going to a restaurant for dinner, Taylor said: You don’t do it every night, but it’s enjoyable when you do.
“If people were more responsible, in one way or another, for those costs, they’d be much more judicious of their use,” Taylor said. “Instead of being the default of every trip, it would be one among an array of choices that have advantages and disadvantages.”
What’s in the way of reducing car usage?
The free market did not create car supremacy by itself, though the government played a big role. The government has the power to change how city-dwelling Americans use their cars, but doing so on the scale needed to truly combat climate change isn’t easy.
City planners contend with regulations that promote driving, and politicians who want to change those are often met with pushback from constituents. In overcoming this, it’s important to remember that not every change needs to be a grand one — yes, a gas tax hike might help but so will more popular measures like bike lanes. And incremental advances, like new zoning regulations rolled out a few neighborhoods at a time, for instance, could have a large impact in the long run.
Also, a multimodal city does not mean cars will be obsolete. Some trips, like to a hardware store, will always necessitate vehicles, and there’s a role for ridesharing as well. But policies are needed to ensure other modes receive a fair shot. It’ll make us safer, maybe happier, and will give our planet a better chance of survival.