In California tests, self-driving cars still require human help

Futuristic self-driving cars traveling along California roads have needed plenty of old-fashioned human intervention to stay safe.

California's Department of Motor Vehicles on Tuesday released reports filed by seven companies the agency gave permission to test prototype vehicles in public. The documents summarized instances in which a human driver had to take over due to technology problems or other safety concerns.

The reports show wildly different levels of success since on-road testing started in September 2014.