The common exposure measures used by the United States National Highway Traffic Safety Administration (NHTSA) are highlighted, with the emphasis on travel data. An overview is given of crash components and a general description of available exposure measures is provided. Details are given of the exposure measures used by NHTSA. The crash model used divides the time sequence into three phases: pre crash; crash; and post crash, considering human, vehicle and environmental factors in each phase. NHTSA has four major crash data systems that can serve as a source of exposure data. Sources of vehicle miles of travel are described. These are classified according to the urban and rural roadway function class. Examples are given to show the relationships between vehicles involved in crashes and vehicle miles travelled, and the drivers involved in crashes and involvement rates by sex and crash severity.
Abstract