March 26


Peak Hour Factor Data Update

By Mike Spack

March 26, 2013

In December I wrote about Peak Hour Factors (PHFs) and included a spreadsheet with about 3,500 peak hour counts we've done at Traffic Data Inc.  Kordel rightly commented about cross-referencing the data against the total entering volume at the intersection (as the Highway Capacity Manual does).

It's taken a little while, but we entered that data and here's the updated spreadsheet - Download Peak Hour Factor MN Analysis.  I'm hoping ITE's SimCap committee will take on the role of being a hub for this type of data (without putting it behind ITE's firewall) – I've talked with Dave and Orla about this type of thing.

Here are the average Peak Hour Factors from our Minnesota dataset:

  • Total entering volume greater than or equal to 1,000 vehicles per hour:  0.93
  • Total entering volume less than 1,000 vehicles per hour:  0.88

This is slightly different than the 0.92 and 0.90, respectively, recommended in the 2010 Highway Capacity Manual.  It would be great if other folks would slice and dice the data in the spreadsheet to look at the PHFs from different angles and put there thoughts in the comments section.  Does anyone know where the HCM's 0.92 and 0.90 recommendations came from?

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    Mike Spack

    My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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