Some Cities Are Actually Cutting Transportation Emissions. Here’s How.
By Laurie Mazur
Our nation’s climate-changing carbon emissions have declined overall since 1990, but one sector — transportation — is headed in the opposite direction. Transportation remains the largest emitter of greenhouse gas emissions in the United States, accounting for 29 percent of the country’s total. After a brief, pandemic-related drop of 13 percent in 2020, transportation emissions accelerated in 2021, increasing by 12 percent.
But local governments and metropolitan regions have the power to bend the curve of transportation-related emissions. It is municipalities, for example, that determine the location of jobs and housing, and therefore the length of commutes, through zoning laws and other land-use regulations. Longer, more-car-dependent commutes mean more climate-changing emissions.
According to the American Council for an Energy-Efficient Economy’s (ACEEE) just-released 2024 City Clean Energy Scorecard, 31 of the 75 cities studied have set targets to reduce their emissions from transportation. Several of those cities are actually seeing progress at reducing those emissions, and the range of approaches they are using should inspire other localities to strive for the same.
San Francisco took the top spot in the ACEEE scorecard for transportation, winning points for its excellent transit service, bike network and numerous EV charging stations. The city’s transit agency and central school district are also working to electrify their bus fleets.
Portland, Ore., came in second on transportation, in part for its efforts to reduce emissions by promoting affordable housing near public transit. Equity is central to Portland’s decarbonization efforts: The city’s Transportation Wallet program gives low-income residents an annual transit pass preloaded with $200, membership in a bike-share program and a $75 prepaid Visa card for other transportation expenses. Oakland, Calif., which placed third, also prioritizes equity: The city favors affordable housing developments located within a third of a mile of public transit.
Those cities and others making progress on controlling transportation emissions are employing a range of strategies and approaches:
Plans and targets. Cities that have successfully reduced emissions set out comprehensive plans to decarbonize mobility. San Diego’s 2015 Climate Action Plan set a 2030 target to reduce per capita emissions from transportation, and the city is on track to achieve that goal. It is seeing per capita emissions decline by about 2.4 percent annually — one of only four cities in the report with a downward trend. According to city data, much of that decrease comes from more-efficient vehicles and the rapid adoption of EVs, thanks in part to California’s robust incentives for EVs and chargers.
Zoning changes. After World War II, zoning was used to segregate manufacturing from residential areas, while a massive investment in highways fostered sprawl. As a result, Americans typically spend an hour getting to and from work each day, mostly by car. Many cities are rethinking that zoning model, adopting codes that encourage walkable, mixed-use, “location-efficient” communities. For example, Spokane, Wash., modified its zoning code to allow up to four units per lot in all residential districts, allowing more people to live near employment and transit. Charlotte, N.C.’s new code eliminates parking minimums in some areas, fostering more density and encouraging transit use.
Alternative ways to get around. Still, 87 percent of daily trips in the U.S. are made in private vehicles. Investments in transit, bicycle and pedestrian infrastructure are key to turning that around. And cities can actively encourage other modes of transportation. Encouragement may take the form of incentives, like Portland’s subsidized access to transit and bike-share programs. Or it may involve disincentives, like New York City’s congestion-pricing plan, which, if it survives legal challenges, will charge drivers for entering Manhattan’s central business district. It would reduce pollution while raising $15 billion for the city’s transit system. Similar plans are under consideration in other cities, including Portland and Los Angeles.
Efficient vehicles. Adoption of EVs and hybrids has been limited by high prices and a dearth of charging stations. Many cities are working to change that by offering incentives to purchase cleaner vehicles and by building out their charging infrastructure. For example, Los Angeles offers a $1,500 rebate on the purchase of a used EV, with an additional $1,000 for low-income, senior or disabled customers. Denver offers rebates of up to $2,000 for homeowners to upgrade wiring and install EV chargers; the city is also working to provide electric car-share vehicles and chargers at affordable housing in under-resourced communities. At the same time, many cities are switching their bus fleets from diesel to electric.
Efficient freight systems. Fully 30 percent of transportation emissions come from the trucks that ferry freight into and out of our cities. As such, efficient freight is an important — and underutilized — opportunity to reduce emissions. Successful strategies include truck-loading plans that utilize space more efficiently, last-mile delivery solutions (such as bicycle deliveries) and off-hour delivery programs. Open data portals can boost efficiency by providing real-time information that helps freight carriers reduce congestion and idling. Oakland, for example, has a sustainable freight plan and an open data portal, and is working to replace diesel-fueled cargo handling equipment with cleaner alternatives.
The carbon-spewing cities we inhabit today were not inevitable, and they are not immutable. Our cities were shaped by decades’ worth of decisions on transit, land use and more. Today, local governments must make different decisions. Of course, cities can’t do it alone; transportation policies are often shaped by states and regional planning organizations. But local governments can build on the efforts of those larger jurisdictions. In this way, we can bend the curve of carbon emissions while making our cities greener, fairer and easier to navigate.
Laurie Mazur is the editor of the Island Press Urban Resilience Project, which is supported by The Kresge Foundation and The JPB Foundation.
This article was published in collaboration with the Island Press Urban Resilience Project, which is supported by The Kresge Foundation and The JPB Foundation. It was originally published May 21, 2024 on Governing.
