What is scenario-based testing for ADAS and AV validation?

Scenario-based testing validates system performance across defined driving situations. Scenarios specify: Road geometry, traffic participants' initial positions and behaviors, environmental conditions, and expected system response. Sources include: Real-world driving data analysis, accident databases, regulatory requirements (NCAP protocols), and synthetic scenario generation. Testing levels: Simulation (millions of scenarios quickly), hardware-in-loop (controller testing with simulated environment), vehicle-in-loop (real vehicle with simulated traffic), and real-world testing. Critical scenarios include edge cases and corner cases that may occur rarely but pose high risk. Coverage metrics assess scenario space exploration.