Self-driving test miles zoom in California

Even with auto makers and tech companies sprouting projects across the country, California remains a fertile testing ground for self-driving vehicles.

Dozens of companies are testing autonomous-driving technology on the state’s roads, and they collectively drove at least 2 million miles in the most recent statistics reported to the state’s Department of Motor Vehicles, which were released last week. That’s more than four times the 500,000-mile total compiled during the last reporting period and perhaps a signal that, despite whatever broad industry headwinds self-driving technology has faced in recent months, research and development is continuing at an accelerated pace.

In reality, the mileage numbers likely are higher, but just 48 of the 62 companies permitted to test autonomous vehicles in California were required to file reports.