Base Free Flow Speed

[Cheese]

I am trying to solve a Level of Service problem given several (many different factors).

I have found the heavy volume factor (fhv) then found the Peak hour flow rate (vp).

Now I want to calculate free flow speed (ffs) using ffs = bffs-flw-flc-fn-fid.

I know how to finish the problem and look up density vs the level of service table.

How do I determine BFFS? NO speed at all was given in the problem. Am I missing a table?

Thanks,

Cheese

 

[AJK]

Assuming this is a FREEWAY SEGMENT, and the base free flow speed is not given,

I believe the BFFS is 70 mph for an urban freeway or 75 mph for a rural freeway.

This comes from the HCM (I think chapter 23), I don't have it in front of me now.

Andrew

 

[redrum]

yes its an assumption (or a given) I dont have my HCM here, but in the beginning of the chapter it should state a given starting point, I think its 70, and then you subtract for all the different factors.

also check out the worksheets, they really give a lot of info