Introduction

Printable Version

The Highway Capacity Manual Applications Guidebook (HCMAG) is intended to assist transportation professionals with the appropriate use and interpretation of the analysis methodologies contained in the Highway Capacity Manual. It uses actual case studies as a means of educating practitioners on how to properly apply these methodologies and when to use alternative means of analysis and evaluation. Each case study begins with a description of one or more interconnected transportation facilities located somewhere in the United States. As part of this description, a number of performance-related issues and problems are identified that require resolution, and these are translated into a series of problem statements subsequently addressed in sequential order. The problem discussions provide detailed information on such issues as data requirements, selection of an appropriate analysis procedure, evaluation and interpretation of the analysis results, and  next steps.

The HCMAG aims to provide specific guidance to users of the Highway Capacity Manual (HCM) in defining and scoping the problems that are to be addressed, identifying and using the appropriate analysis procedures, and tools, and interpreting the analysis results and understanding what they mean. Within the definition and scope of the problem, the HCMAG provides guidance in identifying the appropriate parts of the transportation system that should be included, the most appropriate performance measure to focus upon, the available and appropriate tools for application, the manner in which solution alternatives can affect the problem definition, and the types and quantities of data that will be required. With respect to the analysis applications and tools, the HCMAG provides guidance in identifying application steps where special care and attention is appropriate, understanding how multiple HCM analysis methodologies are consistent (or inconsistent) with one another, and recognizing the conditions under which the application of analysis tools outside the purview of the HCM may be warranted. Finally, the HCMAG provides guidance in the analysis and interpretation of results by assisting the user in determining whether the results are reasonable and consistent, understanding why sensitivity analysis is important and how to conduct a sensitivity analysis, determining what solution alternatives are feasible, learning how to present the results to decision makers in a concise and understandable fashion, and recognizing the possible next steps in the investigation that the analysis results point toward.