If cars are able to drive without human direction, that would mean more people on the road. The specifics of what that would look like depend on a lot of unknowns — the prevalence of car-sharing in the future and the regulations surrounding autonomous vehicle operation, for instance — but two researchers at the University of Michigan have decided to take a crack at guessing how many more cars would be on the road if fully autonomous cars became widely available.
Their best guess, published this week, is that the use of self-driving cars would increase driving among 18-39 year olds by 10.6 percent. Michael Sivak and Brandon Schoettle, both studying autonomous vehicles at the University of Michigan’s Transportation Research Institute, pulled from survey results asking people in that age range why they didn’t have driver’s licenses.
It turned out that a big piece of 18-39 year olds don’t have driver’s licenses for reasons that would be moot if autonomous vehicles were present. For instance, 26.9 percent of the respondents were too busy or didn’t have enough time to get a license. Another 6.1 percent didn’t drive because of a disability or medical problem, while others simply never learned to drive or couldn’t drive because of a “legal issue.”
Others had reasons that the authors acknowledged might or might not become moot if cars were able to drive themselves — like having access to other people with cars willing to drive them.
Some reasons wouldn’t change at all if autonomous cars were introduced, such as preferring public transportation or wanting to avoid the cost of owning and maintaining a car.
The availability of self-driving cars might happen sooner rather than later. The United Kingdom-based firm Juniper Research estimated Dec. 1 that there will be 20 million self-driving cars on the road by 2025, provided that customers begin to embrace the technology by 2021.
That would represent only about 1 percent of cars, according to Juniper. Sivak and Schoettle's report works on the assumption that fully autonomous vehicles — not just semi-autonomous, like Tesla Motors has already put on the road — are widely available.
To develop their estimate of drivership increase, Sivak and Schoettle made several assumptions that may or may not come true as self-driving cars become more sophisticated and eventually hit the market. One was that people would continue to mostly own cars privately instead of share them — an assumption others have found to be unlikely. The consultancy KPMG published a report in October theorizing that more people might choose to buy into car-sharing schemes in the future as opposed to owning their own vehicles. Because cars could drive themselves, a customer could summon a car that would come pick them up, and possibly set up automatic carpools to maximize route efficiency.
Sivak and Schoettle also assumed that “range anxiety,” or the fear that an electric car’s battery would give out before completing a trip, wouldn’t change with the advent of self-driving cars. The companies developing autonomous vehicle technology — Tesla, General Motors and Google, to name a few — are trending toward putting the tech in electric vehicles. Another assumption was that trip patterns wouldn’t change as more people take to the roads.
Many of those things might change. For instance, current California law requires that all autonomous vehicles have a steering wheel and that a person capable of taking over for the car — with a driver’s license, in other words — be sitting in the driver’s seat while the vehicle is moving. In Texas, where Google is testing self-driving cars in the state capital, there are no regulations governing AV use — so theoretically, a car without a steering wheel is fair game.
Though the researchers estimate an increasing amount of traffic on the roads, that doesn’t necessarily mean traffic congestion will get worse. The Senseable City Lab at the Massachusetts Institute of Technology, for instance, has worked to model intersections where, instead of waiting at a traffic light, traffic flows through seamlessly without collisions or stops.
“Imagine a city without traffic lights, where lanes of cars merge harmoniously from one to the next, allowing traffic to flow smoothly across intersections,” a description of the lab’s project reads. “This futuristic vision is becoming reality. The development of autonomous driving promises to revolutionize the landscape of urban mobility, for a safer and more efficient city, across all modes of transportation.”