Google's landmark deployment of autonomous cars — vehicles that can drive themselves — onto public roads and into live human traffic last summer and early fall was announced casually, and after the fact.

Astonishingly, the search-engine giant was able to set loose seven Toyota Prius hybrids, all adorned with a dizzying array of odd-looking sensors, onto Highway 1 between San Francisco and Los Angeles for several months without raising suspicion. Each vehicle was piloted by artificial-intelligence software designed to interpret the data collected by the sensors and use it to mimic the decisions made by a human driver. The goal: to fundamentally change the way we use cars.

How so, you ask? Google believes that the use of autonomous vehicles could nearly halve the number of automobile-related deaths — which it estimates at 1.2 million worldwide per year — because computers are theoretically more precise drivers than humans. In addition, the instant reaction time and 360-degree awareness of computer-controlled vehicles would allow them to ride closer together on the highway than vehicles driven by humans, thus reducing traffic congestion. And finally, they can be more fastidious with the accelerator, reducing fuel consumption and carbon emissions considerably.