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In 2020, Robocars Increase Traffic Congestion

There's a lot of speculation going on about the impact of self-driving cars, or robocars, on different aspects of life. Toyota is the first automaker to admit to their negative effects in the short-term. States Ken Laberteaux, Toyota Senior Principal Scientist, "U.S. history shows that anytime you make driving easier, there seems to be this inexhaustible desire to live further from things," (Business Week, July 21). This means private self-driving cars on freeways will induce sprawl - building new homes with long commutes far from jobs.  In  transportation planning, this is a well-understood phenomenon and can be expected for early robocar market penetration (e.g. from 0 to 15%). Further, as CARS' Sven Beiker points out, robocars may grab market share from public transit, further increasing congestion.

While no major US region has run a forecast envisioning 10% private robocar penetration on freeways, transportation planning theory predicts that more robocar commuters will be willing to brave peak commute hour (while they blithely play on their smartphones), inducing more traffic congestion. Legacy human drivers suffer as a result.

Regions are just beginning to grapple with these "robocar induced demand impacts," which means they haven't yet proposed mitigation strategies. Most mitigations will not be popular with robocar owners . For example, one strategy might be to require private robocars to have two or more people in the car in order to enable freeway autonomous driving - addressing traffic congestion through carpooling.

In a 2025 timeframe, RoboTaxi systems offer the promise of achieving "carsharing benefit:" each car share vehicle eliminates 10 private autos, and each car share member drives 45% less. With higher levels of market penetration, freeway robocars might reduce freeway traffic congestion by forming "platoons" where robocars safely drive bumper to bumper.