Evaluation of Traffic Operations, Safety and Positive Guidance Projects. Volume II in a Series on Positive Guidance

摘要

The report is for use by highway and traffic engineers and technicians in implementing an evaluation of Traffic Operations, Safety and Positive Guidance projects. Evaluation should begin in the planning stage where evaluation designs are selected and measures of effectiveness (MOE's) identified. It should continue during the solution development phase where the measures are used as diagonostics and culminate in an evaluation where differences are in the measures taken before and after the improvement are used to asses the effectiveness of the solution. The Evaluation report provides a cookbook approach to implementing the procedure. This enables those engineers and technicians who are not versed in accident or accident surrogate MOE's, experimental design or statistical analysis to determine whether their solution is effective. Each step in the evaluation is structured in terms of inputs, outputs, and the logic involved in its execution. Tables and worksheets lead to the development of a detailed evaluation plan, data collection procedure and data analysis routine. Among the factors detailed are the selection of appropriate MOE's, overcoming threats to the validity of the evaluation, ways to assure Before and After comparability, how to select the proper statistical test, establishing an appropriate confidence level and recognizing the importance of practical significance.