Driverless cars won’t save the planet if we use them all the damn time
Will vehicle automation make us rely on cars over greener alternatives?
More miles, more carbon emissions
Research has previously suggested that automated vehicles could cause people to drive more than they currently do, leading tomore congestion, energy consumption and pollution. Riding in a car as a passenger is much less stressful than driving, so people might be willing to sit through longer trips and battle more traffic if they can relax and do other things during the journey. The promise of a relaxed, comfortable commute to work could even make some people move farther away from their workplaces and accelerate suburban sprawl trends.
People would also have the ability to send their cars on “zero-occupancy” trips, or errands without passengers. For example, if you don’t want to pay for parking downtown, at some point you may be able to send your car back home while you’re at work and summon it when you need it. Convenient, but also twice the driving.
This could be a big problem. The transportation sector is alreadythe leading contributor to U.S. greenhouse gas emissions. States like California with aggressive plans to combat climate change have recognized thatreducing the number of vehicles miles that people travelis a critical strategy. What if automated vehicle technology makes it harder to achieve these goals?
The real-world environmental impacts of automated cars
While we and other researchers havepredicted these outcomes through modeling, no one has been able to verify them because fully automated vehicles aren’t commercially available yet. We found two innovative ways to use currently available technologies to study the real-world impacts of automated vehicles.
In a study published in mid-2021, we surveyed 940people who drive partially automated vehicles. Systems likeTesla’s Autopilotcan assist with driving tasks and reduce the burden of driving, although to a lesser degree than fully automated vehicles will.
We found that drivers who used Autopilot drove an average ofnearly 5,000 more miles per year than those who didn’t. In interviews with 36 drivers of partially automated vehicles, they generally said they were more willing to sit in traffic and took more long-distance trips, all because of theincreased comfort and reduced stressprovided by semi-automated systems.
In a separate study conducted in late 2019 and early 2020, we simulated the function of a fully automated vehicle by providing 43 households in Sacramento, California, with a chauffeur service to take over the family driving duties and tracking how they used it. These householdsincreased their vehicle miles traveled by 60%over their pre-chauffeur travel, and dramatically reduced their use of transit, bicycling and walking. More than half of the increase in vehicle travel involved sending chauffeurs on zero-occupancy trips without a household member in the car.
Limiting pollution from automated car use
These findings show that automated vehicles will encourage a lot more driving in the future and that partially automated vehicles are doing so now. Is there any way to reap its benefits without making climate change, air quality, and congestion worse?
Requiring future automated vehicles to use zero-emission technology,as California is doing, can be a big help. But until the U.S. develops a100% carbon-free electricity system, even electric cars will produce some upstream emissions from power generation. And all car travel causesother harmful impacts, such as water and air pollution from brake and tire wear, collisions with wildlife and traffic congestion.
To prevent an explosion in driving and associated harms, regulators and communities need to send signals that driving isn’t free. They could do this by putting a price on car travel – particularly on zero-occupancy trips.
The main policies that have this effect today arefederal and state fuel taxes, which currently average around 49 cents per gallon for gasoline and 55 cents per gallon for diesel fuel. But the impact of fuel taxes on drivers’ behavior will decline with the adoption and spread of electric vehicles. This means that the transportation sector will need to develop new funding mechanisms for ongoing costs like maintaining roads.
In place of fuel taxes, state and federal governments could adopt user fees or charges for the number of vehicle miles that drivers travel. Correctly pricing the cost of private vehicle travel could encourage travelers to consider cheaper and more efficient modes, such as public transit, walking and bicycling.
These fees could be adjusted based on location – for example, charging more to drive into dense city centers – or other factors such as time of day, traffic congestion levels, vehicle occupancy, and vehicle type. Modern communication technologies can enable such policies by tracking where and when cars are on the roads.
Another option would be to promote shared fleets of automated vehicles rather than privately owned ones. We envision these as commercial companies, similar to Uber, Lyft, and other ride-sharing providers. Having a car available when needed could make it possible to forgo car ownership and could serve travel demand much more efficiently by essentially acting as on-demand transit. These networks could also help riders reach fixed-route public transportation services that operate on main transportation corridors.
All of these policies will be most effective if they are adopted now, beforeautomated vehiclesare widespread. A transportation future that is automated, electric, and shared could be environmentally sustainable — but in our view, it’s unlikely to evolve that way on its own.
This article byGiovanni Circella, Director, 3 Revolutions Future Mobility Program,University of California, andScott Hardman,Professional Researcher, Plug-in Hybrid & Electric Vehicle Research Center,University of California, is republished fromThe Conversationunder a Creative Commons license. Read theoriginal article.
Story byThe Conversation
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