Not so fast with those self-driving cars.

Once thought to be "green," autonomous vehicles may increase fuel consumption and greenhouse gas emissions

I’ve been a little cool to self-driving cars. First and foremost, I’m a Luddite who—despite my use of a laptop and the internet—thinks the only beneficial technological developments in the last 50 years are the frost-free freezer and the ability to take snapshots without those hideous red glows in our eyes.

But self-driving cars are here, and I know a few folks who have bought cars with self-driving features or are participating in some trials of Tesla’s self-driving vehicles. OK, I’m a Luddite, but my initial reaction is that, given how prone people are to error, self-driving cars may cut down on crashes, which is a really good thing. In 2021, automobiles killed almost 43,000 individuals on America’s highways. If we hadn’t grown used to people dying in such great numbers over the years, we would be in an uproar.

Second, self-driving cars may cause us to revert to being a far less-sober society. Way back, 50, 60 years ago, before Mothers Against Drunk Driving spearheaded reforms to drunk driving legislation, people drank much more than they do now. People would drink and drive, too. Lot of people died because there were so many drunks behind the wheel. In 1970, more than 54,000 people died in automobile fatalities, almost 10,000 more than today, even though we are driving about two-and-a-half times more than we were 50 years ago.

With an autonomous designated driver, folks may feel free to have that second or third mixed drink before they hit the road. The reforms that MADD brought about may no longer be needed and we may become less sober.

Self-driving cars were supposed to save emissions. Well … maybe yes, maybe no

Industry and even some environmentalists, are touting autonomous vehicles (AVs) for their ability to save on fuel. AVs can reduce stop-and-go driving, which is a BIG energy drain, by moderating their speed so as to avoid stopping at red lights. A development that is already part of some driver-assisted features, Adaptive Cruise Control, can reduce fuel consumption by up to seven percent as it properly gauges the distance between your car and the car ahead of you. Self-driving cars, coordinating in consort in what is called “platooning,” reduce air resistance and can achieve fuel savings of seven percent as well. Added up, it would seem that self-driving cars would be the next step to getting us a little closer to green.

Further research, however, is finding that AVs could actually make things a little bit worse, increasing both energy use and emissions. A study from 2021 published in the International Journal of Environmental Research and Public Health found great fuel savings from AVs, as much as 35 percent. The researchers also found that AVs were used a lot more than regular cars, leading, paradoxically, to an overall increase in fuel use by more than 41 percent.

People who can’t drive, such as the the very elderly and some disabled folks, can use AVs. While that is a very good thing for individual autonomy, it means more people on the road, as much as 16 percent more. The researchers found most of the increase in use, about 41 percent, comes from the ease of using AVs. If your AV is doing the driving, it can make your commute a more pleasant experience. As

Lloyd Alter

wrote in Treehugger in 2021, an AV could be considered an extension of your home, like a moving living room. Watching videos, relaxing with a second cup of coffee on your morning commute, who cares how long your commute might be? Folks may care less about their proximity to work and live in ever more exurban frontiers, increasing commute time and using more energy.

All that self-driving will take energy, too

With a high-powered computer doing the driving instead of our easily distracted brains, cars can go a lot faster and still be safe. Faster cars means lower fuel efficiency. As much as 24 percent of the increase in autonomous emissions is predicted to come from increased driving speeds.

A Waymo self-driving car. Photo: Wikimedia commons

While you’re breezing down the freeway or negotiating downtown traffic, your brain is (or should be) a beehive of activity as you estimate safe driving distance, look for hazards, and follow directions of the roadway signage. Self-driving cars do the same by making millions of calculations every minute. All those calculations take energy. Each one doesn’t take much, but remember, we’re talking lots and lots of calculations.

A team at MIT estimated all the power needed for all those calculations and published the results of their research earlier this year. Their modeling concluded that the computer power needed to drive one billion* autonomous vehicles for one hour each day would nearly equal the total annual emissions from the entire country of Argentina.

What do you think? Are self-driving cars worth it? There will be greater autonomy for many elderly and others who currently cannot drive. There almost certainly will be fewer automobile fatalities. You won’t need a driver’s license; you’ll be spared the trip to the DMV to get the renewal. Are these worth the extra energy expenditure?

X (You can find me on that thing formerly known as Twitter.)

*Currently there are 1.47 billion automobiles on planet Earth.

Could you get hip to that timely tip in an autonomous vehicle?

We can all get self-driving cars. But would we really want to make this song sound dated?

We might not platoon. How about a convoy?