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Shoulder Width - Paved or unpaved shoulder?

Jon Lewis
exp
Shoulder Width - Paved or unpaved shoulder? was posted on August 1st, 2013 at 9:37 AM EDT
regarding Chapter 15: Two-Lane Highways

When doing LOS analysis for two-lane highways, the shoulder width should be provided. Does this include only the paved shoulder width, or should it include unpaved shoulder (gravel) as well? I can't find this referenced anywhere in HCM.

Thanks.

Peyton McLeod
Sprinkle Consulting
RE: Shoulder Width - Paved or unpaved shoulder? was posted on August 9th, 2013 at 9:58 AM EDT

In this context, shoulder width should refer to the paved shoulder only.

Gustavo Riente de Andrade
TECTRAN - T├ęcnicos em Transportes ltda
RE: Shoulder Width - Paved or unpaved shoulder? was posted on August 10th, 2013 at 10:54 AM EDT

Really, the HCM has no reference about that. I agree that the most conservative solution would be to ignore unpaved shoulder.

In 2008, we did a full network HCM analysis in Minas Gerais (Central Brazil) and, looking at the free flow speed data, we found out that the unpaved shoulder seemed to have some effect on speeds. So, as temporary technical solution at the tome, we used half of the unpaved shoulder width as an "effective width" value.

This is not, of course, an academic finding, bur rather a technical solution at the time, which I wanted to share here at the forum.

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