California almost certainly has more self-driving cars and operators on public roads than the rest of the world. That the state is experiencing an autonomous gold rush should not come as a surprise. For a start, its reliably mild, dry, and sunny climate is perfect for road-testing early generations of vehicles that still balk at snow, fog, and heavy rain.
Neighboring Nevada is similarly meteorologically blessed and began licensing experimental autonomous cars several years ahead of California. But the Golden State has the advantage because it’s also home to Silicon Valley, where everything a prospective driverless car manufacturer needs—software engineers, hardware geeks, roboticists, venture capital—is available in a near-endless supply. Virtually every large technology company—and most mainstream automakers—have offices in the Bay Area.