When it is easier to travel in a city in self-driving cars, Mr. Calthorpe said, everyone will want to do so. And when self-driving vehicles are more affordable — which could take years to happen — people who currently rely on public transit while running their errands will instead send their cars to pick up the groceries and the dry cleaning, adding significantly to what Mr. Walters and other urban planners call “total vehicle miles.”

This year, Mr. Calthorpe challenged Silicon Valley to take another look at its housing and transportation problem in a proposal in which he asked: “Can one street solve the San Francisco Bay Area housing crisis?”

In addition to his planning consultancy, Mr. Calthorpe has created Urban Footprint, a company that offers a software design tool for planners, architects and environmental analysts who want to model different kinds of development in urban and regional settings.

He used his software to show that by changing just commercial zoning to permit higher density along El Camino Real — the 45-mile boulevard that stretches through the heart of Silicon Valley from San Francisco to San Jose — it would be possible add more than a quarter-million housing units.

The Valley’s housing crisis can be explained in data that shows that since 2010, the region has added 11 jobs for every new home built; the median home price has reached $934,000; and rents have gone up 60 percent since 2012. One of the consequences of the growing imbalance between housing and jobs is the increasing traffic and congestion, according to an Urban Footprint report.

To avoid congestion, the plan requires efficient mass transit. Mr. Calthorpe has proposed an alternative — autonomous rapid transit, or ART — using fleets of self-driving vans in reserved lanes on main arteries like El Camino Real. Those lanes would allow the vehicles to travel faster and require a lower level of autonomous technology. And the vans could travel separately or be connected together.