Autonomous vehicles (AVs) are coming soon to a road near you. Automakers and software companies are hard at work getting vehicles ready for primetime. Experts predict that, by 2030, the first fully autonomous Level 5 vehicles—which can drive without human back-up and under any conditions—will be commercially-available.
AVs could be beneficial or detrimental for the climate, depending on how they are deployed. Electrifying AVs and incentivizing sharing them may help to rapidly decarbonize the transportation sector – currently the largest contributor to U.S. greenhouse gas emissions. However, a less intentional approach to AV deployment could prove ominous. To ensure that AVs have a positive environmental footprint, lawmakers and regulators must advance policy that is designed to accomplish our climate goals. If federal officials are not up to the task—which, in light of the Trump administration’s disdain for pro-climate policies and antagonistic position on clean car standards, is a particular concern—then states should take the lead.
Climate impacts of AVs are uncertain
Every model estimating the climate impact of AVs shows that carbon emissions could either rise further or fall as AVs are integrated into the existing transportation system. On one hand, fuel use and its associated emissions could increase—by some estimates up to 250 percent. This is due to higher freeway speeds, increased travel from the reduced cost of drivers’ time, increased driving from unoccupied AVs traveling between occupied trips—also known as deadhead miles—and new users such as seniors and young people, who may be currently unable to drive themselves, taking to the roads. On the other, programmed fuel-efficient driving styles and improved crash avoidance—which reduces congestion related to accidents– could bend the curve toward lower emissions.
The outcome is uncertain, but research has consistently demonstrated that the guaranteed way to avoid the more harmful effects of AVs is to ensure that they are electric and shared. University of California professor Dan Sperling came to this conclusion in his book, Three Revolutions: Steering Automated, Shared, and Electric Vehicles to a Better Future. His work is backed up by recent research and reviews including those from the University of Michigan and Ford Motor Company, Center for American Progress, Morgan Stanley, and consulting firm BCG.
AV technology providers too are recognizing the potential of shared and electric autonomous vehicles. In 2017, the rideshare company Lyft—which is developing AV software—committed to providing 1 billion rides per year via electric autonomous vehicles by 2025. Executives at the company have stated that their plan is motivated by a need to reduce emissions. Lyft and other rideshare companies are generally moving in this direction, but it is unclear if other major AV players such as General Motors and Tesla have the same plans or motivations.
Relying on AV companies to make what are essentially public policy decisions is unlikely to result in net-positive climate benefits. Public policy will ultimately determine whether AVs are a boon to environmental protection efforts or part of the problem.
Existing laws provide opportunities
California has a unique role in regulating emissions from vehicles that could be used to influence AVs. The state has historically had some of the nation’s worst air quality, in part because of its geography and in part because of the car-centric nature of its cities’ development. Recognizing the need to help California manage its unique air quality challenges, Congress created a waiver in the Clean Air Act that allowed the state to set more stringent standards for vehicle emissions than the federal government and allowed other states to adopt California’s standards. Thirteen states and the District of Columbia, which collectively cover about 25 percent of the U.S. vehicle fleet and vehicle miles traveled, have adopted California’s stricter emissions standards. Nine of these states also participate in California’s zero-emission vehicle (ZEV) mandate that requires major manufacturers to provide a certain number of electric vehicles in those states.
California’s waiver authority and its ZEV mandate could stave off a dramatic rise in emissions from AVs. Cars, including AVs, that are covered by these policies will simply be more efficient. States could go even further and use this authority to require that all AVs be electric. However, the Department of Transportation and Environmental Protection Agency have reportedly threatened to undermine or revoke California’s waiver authority, even though it is needed now more than ever.
Creative new policies can make the best of AVs
Traditionally, transportation regulation assigns state governments authority over the driver and the federal government authority over the vehicle. (There are, however, exceptions, as in the case of California). But clearly the lines begin to blur with driverless vehicles. In the absence of clear federal leadership, 22 states have enacted legislation related to AVs, along with 10 gubernatorial executive orders. Most require study of AVs, permit testing, or comment on issues of liability. Moving forward they should also consider the environment.
States can take the first steps by studying the impact of AVs on the environment. States can go further to reduce AVs’ carbon footprint by setting rules regarding shared autonomous vehicles; who can operate an autonomous vehicle; the number of deadhead miles; and safe driving speeds or distances. And not all rules and regulations need be proscriptive. For example, instead of setting limits on deadhead miles, states could tax those miles to reflect the environmental costs, which would generate much-needed revenue for infrastructure or clean energy. States could encourage people to share AVs independently or through ride-sharing services by providing free access to high-occupancy vehicle lanes or bus lanes for shared AVs. Some states have already done this for electric vehicles. There is a plethora of potential policy innovations states should consider.
If in the future the federal government takes a more heavy-handed role in regulating the safety of AVs—for example, by pre-empting state laws—states’ authorities to manage their AV emissions must be preserved. This is particularly important as the Trump administration stands ready to strip states of transparency measures, research programs, and financial tools used to track and control emissions.
Without checking emissions from AVs, the country will see this transportation revolution radically redirect climate progress while also turning back the clock to a time when poor air quality was a common threat to public health, the environment, and economic wellbeing. AVs can be an integral solution to climate change—so long as states get creative and federal lawmakers support these efforts.
Lia Cattaneo is a research associate for Energy and Environment Policy at the Center for American Progress.
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