Is it possible to determine the PHF from hourly counts?

[TranspoLove]

Good day folks,

I received hourly counts for a permanent counter over the period of a year. The problem is that, the agency I'm doing the calculations for does not store the 15 minute records and they do not have the budget to send someone out there for a week or so to do some counts. So what I've done so far is just assume PHF = 0.88 (rural highway) as per the HCM 2010. The problem is that I think it should be higher; but I don't want to just throw numbers out of a magical basket.

So what I'm doing right now is doing analysis at PHF = 0.88, 0.90, 0.92, and 0.95 and see what happens. However, I'm not really sure that exercise is useful as I don't have any data to compare too or any data to validate.

I would be much more comfortable if I can estimate PHF from the hourly counts, especially since I have a every count over every hour for the whole year.

Thanks!

 

[IRstuff]

This is just a shot in the dark, pun intended, but in electronics we have something called Shot Noise (

http://en.wikipedia.org/wiki/Shot_noise),

wherein the standard deviation of a large number of events, like the Poisson statistics:

http://en.wikipedia.org/wiki/Poisson_distribution

TTFN
faq731-376

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