Peter Calthorpe, one of the creators of New Urbanism, at his office in Berkeley, Calif. He argues that the convenience of autonomous vehicles will only encourage more car trips. Mr. Calthorpe is a Berkeley-based urban planner who is one of the creators of New Urbanism, which promotes mixed-use, walkable neighborhoods. His designs emphasize the proximity of housing, shopping and public space. He is not opposed to autonomous vehicles. Mr. Calthorpe’s quarrel is with the idea that the widespread adoption of personally owned self-driving cars will solve transportation problems. In fact, he worries it will lead to more urban congestion and suburban sprawl. “One thing is certain: Zero- or single-o