Apple isn't the first company to employ California's transportation infrastructure as a giant R&D lab. Alphabet, Tesla and Uber (after some cajoling) have already applied for, and been granted, similar permits.
This news comes as California is warming to the idea of being a high-tech testbed. The DMV recently announced that it would be adjusting its rules to make it easier for companies to test their cars in the state. GM also announced this week that it is dramatically expanding its self-driving vehicle operations in San Francisco and hire 1600 people by 2021.