January 27, 2015

Another Unexpected Consequence of Driverless Cars

Said Tara Grescoe: “The more I read about self-driving cars, the more I realize that nobody knows what they’ll mean for our cities.”

More evidence (something else that never occurred to me) from CityLab: 


How Driverless Cars Could Make Traffic Dramatically Worse


A new simulation-based study of driverless cars questions how well these two big secondary benefits—less traffic and more comfort—can coexist. Trains are conducive to productivity in large part because they aren’t as jerky as cars. But if driverless cars mimic the acceleration and deceleration of trains, speeding up and slowing down more smoothly for the rider’s sake, they might sacrifice much of their ability to relieve traffic in the process. …

… if we want riding in a driverless car to be as comfortable as riding in a train, we need to consider the possibility that more traffic will be the result. Le Vine and company conclude:

Our findings suggest a tension in the short run between these two anticipated benefits (more productive use of travel time and increased network capacity), at least in certain circumstances. It was found that the trade-off between capacity and passenger-comfort is greater if autonomous car occupants program their vehicles to keep within the constraints of HSR (in comparison to LRT).

DriverlessThe work is a reminder that the full benefits of a driverless-car world might take quite some time to materialize—and that we should prepare for the challenges, too. Le Vine acknowledges that congestion might very well clear up once every vehicle in the fleet is autonomous, or even once there are enough to create driverless platoons. Until then, however, the traffic outcomes are much less predictable and very possibly negative.

Consider, for instance, that these simulations didn’t include pedestrians. Doing so no doubt would have led to even more starting and stopping, and thus more delay. And if seatbelts remain mandatory in driverless cars, that might require smoother acceleration and deceleration; much of the comfort of a train ride, after all, is the lack of seat restraints. Traffic behavior would also change if manufacturers offer people several driving profile options—say, from ultra-smooth to aggressive.

All the more reason to think driverless cars will complement, rather than immediately replace, public transportation in cities.

Posted in


If you love this region and have a view to its future please subscribe, donate, or become a Patron.

Share on


  1. My first response is surprise that the safety and health benefits of mass transit aren’t widely known. My second thought is that this argument needs plenty of exposure, though it may not be the most important argument for YES.

  2. There would be more room in the city though as parking spaces can be converted into driving lanes. But it would be better instead if parking spaces are converted into increased space for cyclists, pedestrians and other space such as green space and retail.

  3. I’d speculate the relatively slow acceleration and stopping of HSR is more to do with the fact that they’re long, heavy trains with a lot of momentum – and less to do with passenger comfort. So it seems like a red herring to assume that any passenger cars would change speeds that slow. But the general point is taken – we don’t really know what driverless cars will do to our landscape – can it be any worse than what driverfull cars did though?

  4. Didn’t Google just admit their driverless car couldn’t deal with snow? Not much use for much of North America at this time of year.

  5. Maybe start with driverless buses on the road. Imagine, the freaky experience amongst vehicles with drivers and cyclists.

    Look forward to hearing from partner’s relatives from Germany if they will try mixing as drivers of their car, with the driverless cars in the pilot project on the autobahn between Munich and Berlin (this year?).

    I’m sorry, as a cyclist I don’t welcome driverless cars. Unless they have their own separated road lane. 🙂

Subscribe to Viewpoint Vancouver

Get breaking news and fresh views, direct to your inbox.

Join 7,301 other subscribers

Show your Support

Check our Patreon page for stylish coffee mugs, private city tours, and more – or, make a one-time or recurring donation. Thank you for helping shape this place we love.

Popular Articles

See All

All Articles