# RV's in Freeway Flow Rate problems



## Blu1913 (Sep 5, 2006)

Ok hopefully someone who took the test can answer this one.

If the problem statement mentions nothing about RV's in determining Heavy Vehicle factor in the flow rate equation, do we:

a) neglect RV's

b ) use a default value of .02 for Pr and assume there ARE RV's

Lindeburg neglects them, while the CD course I got from NSPE assumes them. The determination would have a huge result on the answer!

Anyone?!?! :suicide:


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## Road Guy (Sep 5, 2006)

From what I recall there was not anything in the questions that would require you to make an "assumption" in this regard.

It makes sense to always include RV's, especially in the freeway section of the HCM, but I flipped through both that chapter and the ITE Traffic Engineering Handbook and I couldnt find where it said to use a 2% if not given.

Only little trick I see is on page 23-8 where you can consider all HV to be trucks if the % of trucks &amp; buses is at least 5 X the % of RV's

I am working some HCM questions this week and if I come across something different I will let you know.


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## Blu1913 (Sep 5, 2006)

2% was just the value they used in the CD review class.

Im thinking if is doesnt mention RV's to just forget it. I think that might be an assumption too difficult to make without the right info.


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## traffic (Sep 5, 2006)

I would just go with 0 if no rv percentage is given.


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## Road Guy (Sep 5, 2006)

but if they dont give you an RV info do you just go with 0?


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## Blu1913 (Sep 7, 2006)

That is what I will do unless they tell me to incorporate RV's.


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