SUFFICIENCY RATINGS FOR SECONDARY ROADS: MODEL DEVELOPMENT

Work has been done to develop numerical evaluation systems for priority planning use with secondary roads. However, the resulting systems are somewhat local in orientation and are not easily usable in other parts of the country because of differences in road networks, terrain, soil and weather conditions, and even political climate. Most state highway organizations use a form of numerical evaluation called sufficiency rating systems for priority planning. However, this practice is not prevalent in county highway organizations. County highway administrators have used a priority system that is commonly the composite of (a) knowledge of the local road network and its condition, (b) comparison of road conditions with a set of objectives (whether formally or informally adopted), and (c) political expediency. The research reported here was undertaken to develop a sufficiency rating system for secondary roads in Iowa. If a usable system that would yield reasonable results were available, county engineers would have an additional tool to assist them in arriving at a defensible road improvement program. The steps taken to develop the proposed model are recounted in this paper. Described are the instrument used to gather data to choose the rating criteria, the criteria chosen, their relative weights, and the final form of the model.