In this AESIN Conference 2025 presentation, William Latham of HORIBA MIRA introduces CERTUS, a collaborative approach designed to reduce the cost and complexity of verification and validation for ADAS and highly automated vehicles. The talk explores how the industry can build stronger safety cases by answering three critical questions: what to test, how to test, and when enough testing has been done. Through intelligent scenario generation, advanced performance analysis, co-simulation and automated toolchains, CERTUS aims to make safety assurance more efficient while recognising the need for multi-pillared testing across simulation, mixed-reality and physical environments.