ABROAD research program in the field of highway safety has been in progress at the Harvard School of Public Health during the past six years. These studies were initiated by the American Trucking Associations, Inc., the National Association of Motor Bus Operators, and the National Association of Automotive Mutual Insurance Companies.Since 1951 the Commission on Accidental Trauma of the Armed Forces Epidemiological Board, Department of Defense has sponsored research on the human factors in vehicular accidents at Harvard and at a number of other universities and research institutions. Thus far the research program has stressed basic causes in the areas of: 1. Identifying traits of personality and behavior which lead to repeated errors. 2. Defects in the design of equipment (human engineering). 3. Injuries and fatalities resulting from vehicular crashes. 4. Mathematical studies of the various interrelationships of contributory causes in accidents.An extensive review of these and other studies of human factors in highway safety, which has recently been completed as a part of this project, is given here.