The Department of Motor Vehicles in California passed a policy that requires autonomous vehicles to be registered. The agency also issued testing permits and allowed three companies to dispatch 29 cars onto freeways. However, a human behind the wheel is required in case the computer in the car makes a bad decision.

Applications for the permits started 4 months ago and only Mercedes Benz, Google and Volkswagen Group have been issued permits.

According to Bernard Soriano, a DMV spokesman, many companies are completing their applications and more permits are expected to be issued soon.

As it was reported in May, a carmaker that wants to test self-driving cars has to apply for a testing permit, certify its drivers to test the vehicles and secure $5 million insurance.