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95% Queue Calculation

Amarpal Matharu
95% Queue Calculation was posted on September 27th, 2013 at 12:59 PM EDT
regarding Chapter 18: Signalized Intersections

Is there an example problem that shows how the 95% vehicle queue is determined? I've reviewed Chapter 31 though I'm curious if there is a more direct and straightforward explanation of the calculation that would save time versus doing the many calculations outlined in Chapter 31.

Amarpal Matharu
RE: 95% Queue Calculation was posted on September 30th, 2013 at 1:40 PM EDT

In case clarification is needed the following will provide a little more detail behind the question. There are a number of variables presented in HCM 2010 Chapter 18 and the supplemental Chapter 31 and equations are provided to show how one can calculate values for various variables. From interpreting the text report output from HCS some things are open to interpretation when one attempts to correlate between the software values and how to calculate those values utilizing the equations in the HCM. Is there some sort of reference that pulls necessary equations from the two HCM chapters and walks you through the process of calculating the 95% queue? In an attempt to hand calculate the average queue and have it match the value on the HCS report I was able to get a value very close, but not exact. There are a few variables I'm not certain of as I see selection of their value based on text in the HCM could be interpreted more than one way and result in different values based on approaching the problem from different perspectives or with different assumptions. The goal is to remove the uncertainty about methodology applied via HCS and to limit the time associated with trial and error calculations of queues that aim to match the HCS output.

Brandon Nevers
Kittelson & Associates, Inc.
RE: 95% Queue Calculation was posted on October 5th, 2013 at 6:28 PM EDT

Based on your situation I recommend applying the CH 18 computational engine and examining/comparing the results on a 'line-by-line' basis. All friends and members of the committee have access to the computational engine. If you are not already a friend or member, go to and click on "Become a Friend". Once that is established you can download the computational engine from the page of the Signalized Intersection Subcommittee.

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