Eventually, self-driving cars will become our new reality. They’ll bring advantages, better traffic flow and improved safety and energy efficiency. But that doesn’t necessarily mean fully autonomous cars will have the positive impact on the environment people are counting on.
- A study from the University of Michigan claims self-driving cars could negatively impact the environment.
- People’s driving habits will change in autonomous vehicles, possibly increasing travel by car.
- If people no longer view traveling as time lost, what will the incentives be for staying off the road.
A study coming out of the University of Michigan and published in the journal, Applied Energy, found that the benefits of self-driving cars could actually offset the gains. According to a team of researchers at the U-M School for Environment and Sustainability (SEAS) led by Dow Sustainability Doctoral Fellow Morteza Taiebat, there are two reasons at play.
Will Autonomous Cars Increase Travel
Since autonomous cars make driving less of a hassle, they could induce increased driving. And, those extra miles offset energy savings. Previous studies show that some people will travel extra miles because they have better fuel efficiency, in a behavioral change called the rebound effect.
Also, autonomous cars create productive time where there was none. Once driving duties are relinquished to the car, we have the commute time to do with as we will. We can sleep, watch a movie, have a gourmet meal, work on a report, among countless other things. In fact, I can see people using autonomous cars as a place to go to get away from distractions, just driving around with no specific destination in mind – think of it as a mobile Starbucks.
Advantages Could Become Environmental Disadvantages
A decreased energy expenditure and greater time utilization incentivizes people to get into an autonomous car more frequently, thus increasing mileage. These changes in driving habits could partially if not completely offset any energy savings. Moreover, the added travel could potentially increase energy consumption in a phenomenon U-M researchers call backfire.
“The core message of the paper is that the induced travel of self-driving cars presents a stiff challenge to policy goals for reductions in energy use,” said co-author Samuel Stolper, assistant professor of environment and sustainability at SEAS.
In a departure from previous studies, Taiebat and his colleagues examined time cost in addition to fuel cost. He concluded that focusing exclusively on fuel-cost without time resulted in an overestimation of the advanced technologies benefits to the environment.
Time Cost Must Be Taken Into Consideration
Currently, the time we spend driving is viewed as a cost, billable hours lost or time taken away from other desirable activities. In an autonomous vehicle, we perceive the travel time cost as less. Therefore, it’s easier to make the decision to get in the autonomous car and travel somewhere you wouldn’t necessarily go if you had to drive yourself.
This confluence of factors induces more travel, which could cause “backfire”— a net rise in energy consumption. According to the researchers’ estimates, the induced travel resulting from a 38% reduction in perceived travel time cost would completely eliminate the fuel savings associated with self-driving cars.
Behavioral Changes Must Be Considered In The Equation
A great deal of this speculation is based on the assumption that the energy we use in Autonomous cars will result in more carbon emissions and not carbon neutral alternatives. But, if these phenomenon prove to be true, then we need to rethink the design and capabilities of autonomous vehicles. Otherwise there’s the possibility of net increases in local and global air pollution.
“Thus, much higher energy efficiency targets are required for self-driving cars,” said co-author Ming Xu, associate professor of environment and sustainability at SEAS and associate professor of civil and environmental engineering at the College of Engineering.
For us to survive on this planet, we need to reduce greenhouse emissions. Autonomous cars offer a viable solution – but only if we pay attention to how people will use the technology and account for it.