maximus808
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These questions are from the 11th edition of the CERN. Another forum member from ppi has posted some responses. Could you please give your responses and feedback as well, thanks.
Transportation
Example 73.3
1. Is fp(driver population) always assumed to be 1.0?
No. It could be 0.75 to 0.90 for weekend
2. Is the number of lanes only in one direction?
yes, per CERM
3. Be sure to tab HCM for FFS factors!
Ok
4. Refer to B) is speed during peak hours the same as FFS, free flow
speed?
No. There a difference b/w FFS and vp(flow rate for peak 15-min)
5. Refer to B) is FFS the same as average speed S?
No
6. Refer to d). LOS, always go to the next higher density and FFS to
find LOS.
Yes. It's safe to round up for accuracy than to tound down
Example 73.4
1. How do you know to assume FFS=65mph? and PHF=0.92?
It's in the problem
2. How do you distinguish V vs. vp?
They will let us know which one to use (I would assume)
Example 73.5
1. for factor lc (lateral clearance), why is it 0.9? from HCM chapter 21?
why is left-edge lateral clearance taken as 6'?
2. How to distinguish service flowrate vs. Volume?
Transportation
Example 73.3
1. Is fp(driver population) always assumed to be 1.0?
No. It could be 0.75 to 0.90 for weekend
2. Is the number of lanes only in one direction?
yes, per CERM
3. Be sure to tab HCM for FFS factors!
Ok
4. Refer to B) is speed during peak hours the same as FFS, free flow
speed?
No. There a difference b/w FFS and vp(flow rate for peak 15-min)
5. Refer to B) is FFS the same as average speed S?
No
6. Refer to d). LOS, always go to the next higher density and FFS to
find LOS.
Yes. It's safe to round up for accuracy than to tound down
Example 73.4
1. How do you know to assume FFS=65mph? and PHF=0.92?
It's in the problem
2. How do you distinguish V vs. vp?
They will let us know which one to use (I would assume)
Example 73.5
1. for factor lc (lateral clearance), why is it 0.9? from HCM chapter 21?
why is left-edge lateral clearance taken as 6'?
2. How to distinguish service flowrate vs. Volume?
