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Modeling Coordinated Phases in HCM 2010

Scott T. Pasterski, P.E.
Keystone Consulting Engineers, Inc.
Modeling Coordinated Phases in HCM 2010 was posted on September 12th, 2013 at 11:24 AM EDT
regarding Chapter 18: Signalized Intersections

Greetings everyone,

I am trying to model an existing signalized interection that is coordinated along the mainline and present for non-locking, uncoordinated phases). The HCM methodology is apparently based on providing stop bar detection for all approaches (fully actuated), which is not the case in the field. The software I'm using (Synchro V. 8) is forcing me to put a detector at the stop bar for the coordinated phase, which is not consistent with the existing conditions.

In short, is this the correct way to model a coordinated phase? I'm a little uneasy coding a "dummy detector" in the program to trick it into thinking it is fully actuated when in fact it is not? Any help would be greatly appreciated!

Thank you in advance!

Scott

Scott T. Pasterski, P.E.
Keystone Consulting Engineers, Inc.
RE: Modeling Coordinated Phases in HCM 2010 was posted on September 12th, 2013 at 11:28 AM EDT

Sorry.....I sent the thread and then re-read it and realized that some words got inadvertently deleted in my first sentance. What I meat to say was that basically the mainline is coordinated and no stop bar detection is present. The side street and other non-coordinated phases are non-locking and have stop bar detection.

Sorry for the confusion........I'd greatly appreciate any help! Thanks, Scott

Brandon Nevers
Kittelson & Associates, Inc.
RE: Modeling Coordinated Phases in HCM 2010 was posted on September 12th, 2013 at 5:25 PM EDT

The statement "The HCM methodology is apparently based on providing stop bar detection for all approaches (fully actuated),..." is an incorrect characterization of the guidance in the HCM for coordinated phases. You will need to follow up with Synchro support staff to understand how to code coordinated phase control within the Synchro software. As a comparison, the HCM Computational Engine for signalized intersections includes an option for “No Detection”.

Here are a few references within HCM 2010 that might be useful for understanding how the HCM defines and applies phase duration:

• p31-12 Coordinated Phase Duration --- provides a description of coordinated phase operation. As described in the last sentence “Detectors are not typically assigned to the coordinated phase, and this phase is not typically extended by the vehicles it serves.” • Exhibit 31-9 --- illustrates the duration of the coordinated phase • P31-22 Determine Equivalent Maximum Green for Floating Force Mode --- describes how unused split time reverts back to the coordinated phase • Equation 31-41 on P31-28 --- provides the HCM2010 equation for calculating the duration of the coordinated phase.

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