This SAE EDGE(TM) Research Report identifies key unsettled issues of interest to the automotive industry regarding the challenges of determining the optimal balance for testing automated driving systems (ADS). Three main issues are outlined that merit immediate interest: First, determining what kind of testing an ADS needs before it is ready to go on the road. Second, the current, optimal, and realistic balance of simulation testing and real-world testing. Third, the challenges of sharing data in the industry. SAE EDGE(TM) Research Reports are preliminary investigations of new technologies. The three technical issues identified in this report should be discussed in greater depth with the aims of, first, clarifying the scope of the industry-wide alignment needed; second, prioritizing the issues requiring resolution; and, third, creating a plan to generate the necessary frameworks, practices, and protocols. NOTE: SAE EDGE(TM) Research Reports are intended to identify and illuminate key issues in emerging, but still unsettled, technologies of interest to the mobility industry. The goal of SAE EDGE(TM) Research Reports is to stimulate discussion and work in the hope of promoting and speeding resolution of identified issues. SAE EDGE(TM) Research Reports are not intended to resolve the issues they identify or close any topic to further scrutiny.