A computerized benefit-cost model was designed for use by state highway departments in the selection of accident-reduction countermeasures to be applied to investigate sites. Two types of wet-pavement accident reduction countermeasures are in current use: those that increase frictional supply and those that decrease frictional demand. Although this project emphasized countermeasures that influence skid number and wet-pavement accidents, the computerized model treats accidents under both wet- and dry-pavement conditions and, in addition, evaluates costs and benefits for geometric and traffic control countermeasures. Thus, the computerized model is a general purpose tool for the selection of accident countermeasures. The tables supplied with and employed by the model include the published accident reduction percentages for most countermeasures currently employed. The model also includes the relations between wet-pavement accident rates and skid number found in Phase I of this project. In addition, the model includes a novel treatment of highway user costs associated with construction zone activities. It provides as output, cost and benefit data that can be compared and used in budgeting.
Samenvatting