When cars are self-driving, they will be driving 11 percent more.

self driving car
via Paleofuture

Recently transit expert Jarrett Walker suggested that self-driving cars might be a coming congestion disaster; most commenters were not impressed, noting that most likely self-driving cars will be shared rather than privately owned. Walker was not sure this was true, suggesting that "The ownership model is closer to the status quo, and the status quo always has enormous power."

Now a new study from Michael Sivak and Brandon Schoettle of the University of Michigan's Transportation Research Institute, "Influence of Current Nondrivers on the Amount of Travel and Trip Patterns with Self-Driving Vehicles", throws more gasoline on the fire.

The authors looked at all the reasons and excuses that people use for not getting a driver's licence, which range from the surprising number one reason, "Too busy or not enough time to get a driver’s license", and the more plausible No.2,"Owning and maintaining a vehicle is too expensive." Alas, only a very small proportion avoid driving because they are "Concerned about how driving impacts the environment."

They looked at all the excuses for not having a driver's licence and calculated how many of them would probably use self-driving cars if they had the opportunity. They conclude that "the availability of self-driving vehicles would increase the demand for private road transportation by up to 11%"

table of excuses© The University of Michigan Transportation Research Institute

The table only considers people under 39 years old because that is the age group they had data for, and surprisingly, who they think will be most affected by self driving cars, noting that older people don't drive long distances, and that 90 percent middle-aged people have licences and will not be much affected. So they extrapolate:

The biggest impact of self-driving vehicles on the amount of travel will likely be in the age group studied in this analysis (18 through 39 years of age). In other words, the obtained increase of 11% in travel with the availability of self-driving vehicles by those 18 through 39 years of age is likely to provide an upper bound for the increase in travel by all persons.

Now these are the experts at the Transportation Research Institute writing, but I can't help but wonder if they are seriously under-estimating the demand from the baby boomer generation. The reason older people don't drive long distances may well be because they are uncomfortable doing it or don't drive at night anymore. Jim Motavalli, writing on MNN, notes that Seniors, not hipsters, will get self-driving cars first.

Brad Templeton, a consultant on the Google self-driving car team in 2011 and 2012, sees that early adopters of the technology will be … senior citizens, baby boomers actually. It may seem counterintuitive — young people usually take the first plunge into the new thing — but in this case it makes total sense.Templeton told The Wall Street Journal that suburban boomers who can’t drive anymore may face the choice of giving up their homes (because the suburbs don't have good public transportation) or putting technology behind the wheel.

The fact that such a high proportion of the 18 to 39 group either can't find the time or don't have the money to drive implies that they are not really motivated to do so. But at the other end of the age scale, the boomers are really motivated. So 11 percent might just be the floor, not the ceiling.

It also begs the question what they all will be doing less of. Will they be giving up on transit? Walking? Whether they are owned or shared also changes the outlook. There really are so many implications for our cities; We really ignore them at our peril.

Tags: Self-driving car | Urban Planning


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