Now that the streetcar has been put on hold, San Antonio needs an informed discussion about the future of mobility in the region. That future is very different depending on whether you look through the eyes of Google or those of urban planners.

Google and other companies are producing new technologies that will vastly increase mobility, while planners seek to reduce mobility. Google’s vision is that self-driving cars will go on the market by 2020, leading to a new transportation revolution.

By 2030, some new cars won’t even have the option of being driven by humans. By 2040, self-driving cars will so dominate the roads that many states will close highways to human-driven cars for safety reasons. Today’s millennials will be in their 40s and 50s in 2040, and any rail project San Antonio may have spent billions to build will have long become obsolete.

By reducing congestion, self-driving cars will allow more people to live in inner cities without the hassles of parking or stop-and-go traffic. But they will also allow more people to live in distant suburbs even if it means long commutes because they’ll be able to work during those commutes.

Self-driving cars will completely transform our society, yet planners for neither the city of San Antonio nor the Alamo Area Metropolitan Planning Organization have considered the effects of self-driving cars in any of their long-range plans. Instead, they are focused on so-called “smart-growth” policies that actually aim to reduce mobility.

Under such policies, 8‑mile-per-hour streetcars are preferred over 70-mile-per-hour freeways. Smart-growth planners in Washington state have actually set targets of reducing per capita driving by 50 percent.

Such plans threaten the mobility that is vital to our economy and our personal freedom. The automobile gives people access to higher-paying jobs, lower-cost consumer goods, better housing and many other things that can’t be reached by transit, bicycles or walking.

By comparison, transit is slow, inconvenient, and irrelevant to most people: only 1 percent of all trips and less than 3.5 percent of commuter trips in San Antonio are by transit. More San Antonians now telecommute than take transit.

Although transit is often presented as a way of helping low-income people, Americans who make more than $75,000 a year are more likely to use transit than Americans who make less than $25,000 a year. Studies have found that the most cost-effective way of helping someone out of poverty is to give them access to a low-cost car, while a free transit pass provides almost no help.

Transit is also expensive, costing four times as much per passenger mile as driving when all subsidies to transit and highways are counted. This means car-sharing of self-driving cars is likely to replace most transit in the future.

Why stand in the heat waiting for a bus or a clunky streetcar when, for a lower overall cost, you can have a car pick you up at your door and take you straight to your destination? If we are still worried about low-income families, giving them transportation vouchers will do more for their mobility than spending hundreds of millions on streetcars or light rail.

Nor is transit greener than driving. VIA’s buses actually use more energy and emit more greenhouse gases per passenger mile than the average SUV. By 2025, the average car on the road will be more energy efficient than even the nation’s most efficient transit systems.

Unable to predict the effects of self-driving cars on future cities, planners instead plan for the past, and try to impose that past through a combination of subsidies and regulation. San Antonio should reject smart-growth plans based on the immobile past and instead look to a future of vastly increased mobility.