Preface. My main post on this is: “Why self-driving cars may not be in your future“.

Alice Friedemann  www.energyskeptic.com  Author of Life After Fossil Fuels: A Reality Check on Alternative Energy; When Trucks Stop Running: Energy and the Future of Transportation”, Barriers to Making Algal Biofuels, & “Crunch! Whole Grain Artisan Chips and Crackers”.  Women in ecology  Podcasts: WGBH, Financial Sense, Jore, Planet: Critical, Crazy Town, Collapse Chronicles, Derrick Jensen, Practical Prepping, Kunstler 253 &278, Peak Prosperity,  Index of best energyskeptic posts

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Taiebat, M., et al. 2019. Forecasting the Impact of Connected and Automated Vehicles on Energy Use: A Microeconomic Study of Induced Travel and Energy Rebound. Applied Energy247: 297

The benefits of self-driving cars will likely induce vehicle owners to drive more, and those extra miles could partially or completely offset the potential energy-saving benefits that automation may provide, according to a new University of Michigan study.

Greater fuel efficiency induces some people to travel extra miles, and those added miles can partially offset fuel savings. It’s a behavioral change known as the rebound effect. In addition, the ability to use in-vehicle time productively in a self-driving car — people can work, sleep, watch a movie, read a book — will likely induce even more travel.

Taken together, those two sources of added mileage could partially or completely offset the energy savings provided by autonomous vehicles. In fact, the added miles could even result in a net increase in energy consumption, a phenomenon known as backfire.

Traditionally, time spent driving has been viewed as a cost to the driver. But the ability to pursue other activities in an autonomous vehicle is expected to lower this “perceived travel time cost” considerably, which will likely spur additional travel.

The U-M researchers estimated that the induced travel resulting from a 38% reduction in perceived travel time cost would completely eliminate the fuel savings associated with self-driving cars.

“Backfire — a net rise in energy consumption — is a distinct possibility.

Mervis, J. December 15, 2017. Not so fast. We can’t even agree on what autonomous, much less how they will affect our lives. Science.

Joan Walker, a transportation engineer at UC Berkeley, designed a clever experiment. Using an automated vehicle (AV) is like having your own chauffeur. So she gave 13 car owners in the San Francisco Bay area the use of a chauffeur-driven car for up to 60 hours over 1 week, and then tracked their travel habits.  There were 4 millennials, 4 families, and 5 retirees.

The driver was free.  The study looked at how they drove their own cars for a week, and how that changed when they had a driver.

They could send the car on ghost trips (errands), such as picking up their children from school, and they didn’t have to worry about driving or parking.

The results suggest that a world with AVs will have more traffic:

1. the 13 subjects logged 76% more miles
2. 22% were ghost errand trips
3. There was a 94% increase in the number of trips over 20 miles and an 80% increase after 6 PM, with retirees increasing the most.
4. During the chauffeur week, there was no biking, mass transit, or use of ride services like Uber and Lyft.

Three-fourths of the supposedly car-shunning millennials clocked more miles. In contrast to conventional wisdom that older people would be slower to embrace the new technology, Walker says, “The retirees were really excited about AVs. They see their declining mobility and they are like, ‘I want this to be available now.’”

Due to the small sample size she will repeat this experiment on a larger scale next summer.