DETERMINATION OF A DISCRIMINANT FUNCTION AS A PREDICTION MODEL FOR EFFECTIVENESS OF SPEED ZONING IN URBAN AREAS

Speed zoning is the application of a different speed limit to a section of roadway than is applicable to adjoining highway segments. In a 1985 Federal Highway Administration survey of state and local transportation officials, four factors received the highest frequency response as part of their speed zoning procedure. In descending order they are: 85th percentile speed, accidents and pace speed tied for second, type and amount of roadside development was fourth. These four factors are measurable in quantitative units and are utilized by a number of states as part of a procedure to adjust the speed limit. The purpose of this research is to identify additional factors which can be used to determine where speed zoning will be effective and to clarify their relationship to raising or lowering the speed limits. The hypothesis is that a quantifiable relationship exists between accident parameters, speed parameters, roadside friction, and environmental/geometric variables such that it is possible to predict the effectiveness of speed zoning in urban areas.