Highway Capacity Manual
Highway Capacity Manual (HCM)
The Highway Capacity Manual (HCM) contains concepts, guidelines, and computational procedures for computing the capacity and quality of service of various highway facilities, including freeways, signalized and unsignalized intersections, rural highways, and the effects of transit, pedestrians, and bicycles on the performance of these systems.
Highway Capacity Manual 7th Edition is Now Available!
A major update to the Highway Capacity Manual was published during the 2022 Transportation Research Board Annual Meeting 2022. This version of the manual is entitled, Highway Capacity Manual (HCM) 7th Edition: A Guide for Multimodal Mobility Analysis.
The 7th edition of HCM includes the following changes:
New Electronic Format - The HCM 7th Edition breaks new ground in that it is the first edition of the HCM that will be available not only inbound, printed format, but also in two electronic formats (PDF and e-book) that are hyperlinked, searchable, and make the HCM truly “portable.” The electronic version also will make all of the Volume 4 chapters readily accessible for offline use.
New and Expanded Procedures – The HCM 7th Edition will formally incorporate significant additions or expansions to computational procedures:
o Guidance on the application of HCM methods to determine capacity impacts of connected and automated vehicles (CAVs).
o A new network analysis method to evaluate spillback between freeways and urban streets, estimate travel time across facilities, and conduct lane-by-lane analysis for freeways.
o A new two-lane highways analysis method that offers improved analysis of two-lane highway capacity and operational performance.
o Enhancements to existing pedestrian analysis methods at signalized intersections and uncontrolled crossings
Significant Errata – The HCM 7th Edition will address all errata and revisions from the HCM 6.
New Corridor Methodology for HCM is now available
The draft final report for NCHRP 15-57 entitled as "Highway Capacity Manual Methodologies for Corridors Involving Freeways and Surface Streets" is now available to download.
The objective of this research project is to develop materials for the HCM in order to modify the freeway analysis methods and the urban street methods so that the effects of operations from one facility to the other can be evaluated. This report summarizes the entire research effort and provides the proposed new HCM Chapter (Chapter 38). The new methods produced can be used to evaluate operations along corridors that include both arterials and freeways. The methods can also evaluate the impact of spillback into freeways and into arterials from downstream facilities.