Maturity in Automated Driving on Public Roads: A Review of the Six-Year Autonomous Vehicle Tester Program

With support from United States Department of Transportation and state policies and regulations, in recent years manufacturers have initiated automated vehicle (AV) testing on public roads. Vehicle autonomy has grown from simulations and controlled environments to real-world driving environments with normal traffic. California is one of the states with an autonomous vehicle tester (AVT) program. It was established as early as 2014 for authorized manufacturers to test their AVs on public roads. This review examines permit holder information, autonomous mileage reports, autonomous vehicle disengagement reports, and autonomous vehicle collision reports over a six-year period. In addition to reviewing operating experience and the growth of AV testing, this study conducted in-depth analysis to evaluate maturity in automated driving technology and reported disengagement causes. It shows that a state-run AVT program boosts maturity in automated driving technology. At the same time, by participating in the AVT program, AV manufacturers showed a trend toward improvement in their AV technologies (e.g., an 8% fall in disengagements caused by hardware and software discrepancies and a 12% fall in those caused by perception discrepancies). States are encouraged to initiate or continue their AVT programs for the benefit of autonomous driving on public roads.