Autonomous vehicles may lead to an increase in miles driven

Autonomous vehicles may lead to an increase in miles driven
Credit: Mario Goebbels

Autonomous vehicles may reduce the number of vehicles a family needs, but may lead to an increase in total miles driven, say researchers at the University of Michigan Transportation Research Institute.

UMTRI researchers Brandon Schoettle and Michael Sivak examined U.S. National Household Travel Survey data that contained comprehensive information about each trip made by a person within a selected household, including the exact start and stop times of each trip.

They found a general lack of "trip overlap" between drivers within a majority of based on vehicle sharing. In other words, families rarely use more than one vehicle at a time.

The study is based on sharing of completely that employ a "return-to-home" mode, acting as a form of shared family or household vehicle. This would mean that driverless vehicles could operate without any passengers at all.

In the most extreme scenario, self-driving vehicles could cut average ownership rates of vehicles by 43 percent—from an average of 2.1 vehicles to 1.2 vehicles per household, the researchers say.

On the other hand, the shift could result in a 75-percent increase in individual vehicle usage—from 11,661 to 20,406 annual miles per vehicle (this increase in mileage does not include additional miles that would be generated during each "return-to-home" trip).

Schoettle and Sivak found that, on an average day, nearly 84 percent of households had no trips that overlapped or conflicted. Just under 15 percent of households had two drivers and less than 2 percent had three drivers with overlapping trips that created a conflict.

The researchers say their results represent strictly an upper-bound approximation of the maximum possible effects of self-driving vehicles on reductions in household vehicle ownership, given several unknowns: sufficient gaps between trips, acceptance and adoption of and possible -sharing strategies within households.


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Feb 12, 2015
Only problem with a RTB option on these vehicle sis you're doubling the number of journies if you go somewhere, rather than driving there, parking up for a few hours then driving home, you'd go there, the car would return to base then when you're ready it would drove back and pick you up then take you home.

Fine if you're using electric vehicles that are all powered from solar, but if petrol / diesel fuelled this will increase the amount of co2 emitted, not to mention it could increase congestion.

Feb 12, 2015
That's amazing, they have the ability to pretend to do research on something which doesn't exist.

Feb 12, 2015
Of course! When u have kids you won't make the trip by the school rather you would make the car drive the kids to school and then you would travel to work or the other way around. Or every person would have a transport vehicle of their own.

Feb 12, 2015
I am finding it hard to believe driverless is going to be feasible. There are many places in this country where roads and intersections aren't clearly delineated. I have the feeling the technology won't be reliable unless it's deployed on restricted sections of roads specially set up to handle driverless vehicles. That probably means some sort of passive transponder every few feet and limited access higways. As soon as one of these things runs over a kid or kills someone when in driverless mode there's going to be a backlash. I could be wrong but I just don't see these things running around just anywhere in driverless mode.

Feb 12, 2015
Fine if you're using electric vehicles


Well you got to factor in battery wear and sufficient intermissions to recharge. Doubling the mileage even in an electric car is a very expensive proposition because of the high cost of replacing worn batteries.

Vehicle sharing without passenger pooling necessarily increases distance driven over passenger mile - that is, the vehicle becomes less efficient. As the article points out, 84% of the trips are non-overlapping.

Feb 12, 2015
This is one of those articles that is just so obvious. Of Course driverless vehicles would lead to more miles travelled. People don't have to drive, they just sit there, so they can ride in the car without having to do the 'work' of driving, not having to pay attention. If my car drove itself, I might just ride around in it for fun!

Did anyone think about how people will drink much more often if they don't have to drive their cars?

Feb 12, 2015
I would think that it wouldn't RTB unless it was requested to. It would park near the last persons trip and be summoned from there to where it's needed. Well... When it can do so at a reasonable price(preferably free parking at the venue traveled to).

Feb 12, 2015
Silly discussion. Just make unoccupied autonomous vehicles illegal.

Feb 13, 2015
Silly discussion. Just make unoccupied autonomous vehicles illegal.


Which is exactly what I think will happen but with exceptions.

Feb 15, 2015
Autonomous vehicles may lead to an increase in miles driven


Good. That can't be done without a vibrant economy and the required cheap and plentiful energy

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