Volume 4 of the HCM supplements the three printed volumes of the HCM with additional detail that many HCM users will find useful. The content of Volume 4 has been divided into the following four major areas, which can be accessed using the links at the top of the page:
Methodological Details. Most Volume 2 and 3 chapters (and one Volume 1 chapter) have a companion Volume 4 chapter. The specific content varies by chapter (see the Introduction section of each Volume 4 chapter for a summary of the chapter’s contents), but will include material in one or more of these areas:
- More-detailed descriptions of computational methodologies, written for users who seek a greater depth of understanding of the methodology or plan to develop HCM implementation software;
- Sensitivity analyses, statistics on methodological uncertainty, worksheets, and data collection forms;
- Example applications of alternative tools to situations not addressed by the Volume 2 or 3 chapter’s methodology; and/or
- Additional example problems and calculation results.
Interpretations. As the 2010 HCM is applied, it is anticipated that users will raise questions about how to interpret various sections of the HCM. Official clarifications, interpretations, and corrections issued by the TRB Committee on Highway Capacity and Quality of Service will be posted here.
Technical Reference Library. The Library contains selected technical reports and companion documents that provide background information about how HCM methodologies were developed. In the future, the Library may also contain research papers being considered for the next edition of the HCM.
Highway Capacity Manual Applications Guide. The Guide provides six case studies that illustrate how to use the HCM to perform common types of analyses. The case studies focus on the process of applying the HCM, rather than on the details of performing calculations (which are addressed by the example problems in Volumes 2, 3, and 4).
Note to reviewers:
This version of Volume 4 is a prototype, illustrating the kinds of content that will be included in the final Volume 4. In particular, please note the following:
Highway Capacity Manual Applications Guide. The original five case studies have calculation results from HCM2000. At this time there is no plan to update the calculations with the 2010 HCM methods, as the focus of the Guide is on applications, rather than calculation methodologies. However, to avoid confusion from users, some text will be added to the case studies and the introductory material that lets the user know that the calculation results in the HCM AG were based on results from HCM2000 and that users should focus more on the application and interpretation guidance as opposed to the actual numerical results, which may change over time as changes are made to the underlying HCM methodologies
Technical Reference Library. The library contains copies of, or links to, key documents referenced in just the 2010 HCM chapters that have been released in draft form. Input is still needed from subcommittees on other documents that should be included in the library.
Methodological Details. Please comment on these chapters’ content directly, rather than through a comment on Volume 4.
Interpretations. HCM2000 interpretations are posted as a placeholder.