This paper builds upon the presentations on the Impact of Human Factors on Safety presented at the FISITA 2021 Intelligent Safety Conference. Sources of information considered include summaries of research issues identified in 2021, the Haddon Matrix, keyword searches, and the authors own research and experience. That research and the authors experience emphasizes the need for greater use of (1) quantifiable research questions, (2) quantifiable outcomes based on human performance models (especially workload), (3)consistently defined measures of driving performance and statistics (e.g. SAE J2944 and beyond), (4) quantifiable measures of traffic and its orderliness, and (5) standard scenario identifiers.