Google's self-driving cars, which use laser sensors and mapping technology, are examples of Level 3 cars, Mr. Friedman said.

WSJ: Self-Driving Cars Spark New Guidelines

Google has suggested it could sell auto makers the mapping and machine-vision technology it's developing for its self-driving cars, or offer that technology for free as part of a package of other Google products and services.

WSJ: Self-Driving Cars Spark New Guidelines