Leon Robertson is a sociologist/epidemiologist. He has conducted research on medical care delivery, the epidemiology of injuries and the effects of various injury prevention and control efforts. The feedback of vehicle use on increased greenhouse gas emissions, resultant warming and increased vehicle use is the subject of his latest research. During 2020, he switched to COVID-19 research and found that negative test results are associated with increased spread of the SARS-CoV-2 virus, apparently due to behavior after receiving a negative test. His book, Roads to COVID Containment and Spread will be published in late 2022.