Cars that can drive themselves without a human being behind the wheel are still years away, but California is starting to grapple with their impact on emissions. This week the Air Resources Board presented new research on how autonomous vehicles could impact the state’s ambitious clean air goals, and the early signs are not looking good.
According to a new study from the University of California, Davis Three Revolutions, so-called connected and automated vehicles or CAVs that can drive themselves and communicate with each other are likely to increase vehicle kilometers traveled and reduce people’s willingness to use public transport Future Mobility Program, that explores shared, automated and electric vehicles.
What you need to know
- Connected and automated vehicles could significantly increase the number of kilometers traveled by car, according to a new study by UC, the Davis Three Revolutions Future Mobility Program
- The study found that privately owned CAVs could travel 40% more miles by 2050
- Traffic congestion could also get worse, especially in the San Joaquin Valley
- CAVs could reduce the use of public transport and domestic air traffic
“These are pretty significant impacts to consider and also frightening for the future of California traffic,” said program director Giovanni Circella.
Using travel demand models for 2050 developed by the California Department of Transportation, UC Davis researchers looked at six different scenarios for CAVs: three for those that are privately owned and three for those that are shared through services such as ridesharing.
The first scenario is similar to the current model of people owning private vehicles, except that the cars would drive themselves. The second examined how private CAV use would affect if road charges made operation more expensive. The third looked at personal CAVs that have no emissions.
Privately owned CAVs that are non-electric and not subject to road tolls increased vehicle kilometers driven by 5 to 40%, the researchers found – “more than what we would have in 2050 if we didn’t have vehicle automation” . said Circella.
With a non-electric vehicle, the more kilometers driven, the more emissions are generated. To reduce the number of kilometers driven, many cities have introduced road tolls to discourage driving. But even at such prices, according to Circella, vehicle mileage could still increase – a situation that was true even for the study’s shared autonomous vehicle scenarios, as personal journeys are likely to increase.
Driverless cars have the potential to dramatically change transportation, but they could also radically reorganize society if people’s perceptions of the safety and comfort of their vehicles change, affecting their willingness to drive, and how long they spend on other activities others can exercise while traveling.
This, in turn, could have an impact on which mode of transport they choose and could even affect where people live, work and relax when long journeys no longer tire and are cheaper.
All of the scenarios that Circella and his team looked at showed the potential to wipe out a significant number of trips by mass transit, long-distance rail, and state airlines. “Within California, the distances are so great that quite a large number of trips that are made by air today could be replaced by the use of CAVs in the future,” he said, citing air traffic between San Francisco and Los Angeles as likely candidate.
While privately owned electrically powered CAVs would not generate the same emissions increases as fossil fuel CAVs, “traffic congestion will still increase,” Circella said.
The largest increase in CAV vehicle miles driven would be in LA County, he added, where VMT is already highest. But places like the San Joaquin Valley in the central part of the state could be dramatically changed by the widespread adoption of CAVs as more people travel through it on their way between Los Angeles and San Francisco and more local trips are made in automated vehicles.
“This study underscores the importance of the early use of emission-free vehicles,” said Circella. “ZEVs will reduce emissions, but other disadvantages of using CAV will remain due to an increase in tourist traffic and a fairly significant increase in traffic congestion that is likely.”
In order to reduce the negative emissions and traffic congestion caused by the use of CAVs, according to Circella, regulators should consider additional guidelines to encourage their use as shared vehicles instead of private vehicles and to coordinate their use as the first and last access to public transport.
While CAVs are years away from widespread adoption, the Air Resources Board commissioned the UC Davis study to understand what policy tools it might now consider to discourage residents from using automated vehicles in such a way that even more emissions are generated than the cars they are currently driving.
Traffic is the state’s largest source of greenhouse gas emissions and presents an exceptional challenge for regulators as California seeks to cut greenhouse gases 80% below 1990 levels by 2050.
“The transportation sector is experiencing rapid changes that have the potential to significantly disrupt people’s mobility,” said Melanie Zauscher of the ARB, contract manager for UC Davis CAV research. “Even if autonomous vehicles are still future technology, several companies are currently testing robo-taxis or ride-hailing automated vehicle services on the streets.”
As of May 21, the California Department of Motor Vehicles had approved 55 companies to test automated vehicles with a safety driver; eight of these companies are also licensed to test vehicles on public roads without a driver behind the wheel, and one of them is licensed to use the technology.
