PHF

VTEnviro said:

I'm not familiar with the PHF method, but am well versed in the GFY system.

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305Gurl said:

I have a project that I am working on. I was given the counts for a particular intersection, but for the life of me I cannot determine how the PHF of 0.92 was determined. I know it is the Peak hour volume/ Peak 15min vol. The most I got was 0.88 found by the following calculation:

The peak hour volume is found between the hour of 7:45 am and 8: 45 am in the westbound direction. This total volume of 1633 is the peak hour volume. This is the sum of the left, through and right turns between 7:45 and 8:45 am, and is the highest 4 intervals of 15 minutes volume. Then PHF = 1633/ (4 * 465)= 0.88. This 465 was found from the highest 15 minute within the peak hour volume (14+444+7).

Could some please tell me what I have done incorrect of was the PHF provided to me incorrect. See counts attached for the intersection.

Thanks a bunch!

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PSU09Vet said:

VTEnviro said:

I'm not familiar with the PHF method, but am well versed in the GFY system.

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I assume this is a close spinoff of the GFYS method? It's what I tend to apply to this subject. :afro:

Very close corollary. Same method of thinking.

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VTEnviro said:

PSU09Vet said:

VTEnviro said:

I'm not familiar with the PHF method, but am well versed in the GFY system.

Click to expand...

I assume this is a close spinoff of the GFYS method? It's what I tend to apply to this subject. :afro:

Very close corollary. Same method of thinking.

Click to expand...

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ptatohed said:

305Gurl said:

I have a project that I am working on. I was given the counts for a particular intersection, but for the life of me I cannot determine how the PHF of 0.92 was determined. I know it is the Peak hour volume/ Peak 15min vol. The most I got was 0.88 found by the following calculation:

The peak hour volume is found between the hour of 7:45 am and 8: 45 am in the westbound direction. This total volume of 1633 is the peak hour volume. This is the sum of the left, through and right turns between 7:45 and 8:45 am, and is the highest 4 intervals of 15 minutes volume. Then PHF = 1633/ (4 * 465)= 0.88. This 465 was found from the highest 15 minute within the peak hour volume (14+444+7).

Could some please tell me what I have done incorrect of was the PHF provided to me incorrect. See counts attached for the intersection.

Thanks a bunch!

Click to expand...

305,

The formula for PHF is PHF = Vvph / (4 x V15 min peak)

I am assuming that the spreadsheet is correct and that 7:45 to 8:45 is the peak hour (it seems like it is)

We get Vvph by adding up all of the vehicle movements within that 60 minute period. This is shown as 3,455 under the Total Pk Hr Volume (I double checked and it is correct). Also, we can see by the diagram 202+11+82+17+1575+41+57+1306+34+48+5+77=3455

What isn't shown on the spreadsheet is V15. Doing some quick calcs to find V15:

V8:00-8:15 = 795

V8:15-8:30 = 939 <---- Use

V8:30-8:45 = 503

So, V15 min pk = 939

PHF = 3455 / (4 x 939) = 0.9199

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ptatohed said:

You're welcome 305. My pleasure.

For some reason, I totally missed PSU's post #4 yesterday. I only saw his post #5! I probably wouldn't have added post #6 had I seen that PSU already demonstrated how to derive the PHF = 0.92. Good job PSU.

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