Summary of research findings from DDADWS meetings 8 and 9 concerning driver drowsiness detection and warning systems. Topics covered include fatigue contributing to 15-30% of road crashes, the safety-critical nature of KSS levels 8 and 9, distinguishing drowsiness from microsleep events, eye-closure behaviour as a practical detection tool with 2-second minimum duration criteria removing 85% of false positives while preserving 90% of true positives, KSS as a validation reference measure, testing environments including simulators and on-road conditions, system performance metrics, observable signs of drowsy driving including lane deviations and ocular indicators, participant demographics and state, ensuring valid drowsiness testing, warning effectiveness and escalation strategies, and evidence-based design factors for drowsiness warnings.