Abstract
Since the 1965 edition of the Highway Capacity Manual (HCM), fundamental curves representing the relationship between speed and volume or flow rate have formed the basis of design and analysis methodologies for basic freeway segments and for uninterrupted flow segments of multilane highways. As the 2010 edition of the HCM was being developed, a new set of freeway speed–flow curves was recommended. Somewhat late in the development process, the recommended curves became controversial. This paper presents the recommended curves and the research behind them and the controversies that affected the outcome. A final set of curves for HCM 2010 was recommended on the basis of extensive comparative statistical analyses of a substantial database and on several conditions that the TRB Highway Capacity and Quality of Service Committee voted to impose on the curves characteristics. Recommendations for the future are made.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Transportation Research Record: Journal of the Transportation Research Board
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
