Highway Capacity Manual Applications Guide Foreword

The Highway Capacity Manual Applications Guidebook contains real-world case studies to illustrate how the Highway Capacity Manual (HCM) and other tools can be used to analyze traffic operations. Although it is primarily intended for new or infrequent users of the HCM, experienced users of the HCM are likely to gain insights also. Graduate students should find the Guide very helpful in better understanding the HCM and the problems faced by practitioners.

The HCM is the most widely used resource for traffic analysis. Software makes the HCM relatively easy to use, but many users lack a thorough understanding of the HCM methodologies. Inappropriate use of this tool can lead to highways that have insufficient capacity, increasing pollution and congestion, or that are overbuilt and wasteful of public funds.

The HCM currently provides only simple example problems to illustrate the methodologies. Complex, real-world problems require more than plugging numbers into formulas. Examples of realistic applications will educate users on how to properly use the HCM for these types of problems. These applications also can help identify limitations in the methodologies, including when their use is inappropriate, and they could be used as resources in training classes and self study.

Under NCHRP Project 3-65, Kittelson & Associates led a research team comprising some of the principal authors of the current HCM. The team identified and assessed difficulties that practitioners face in using the HCM and selected real-world problems featuring the most significant difficulties. They then worked through each case study, showing how the HCM and other techniques can be applied. These case studies were developed to be published as a world wide web site to make them more easily available. A CD-ROM version was also developed, particularly for those without ready access to the Internet.