HCM 2010 Update to the All In One Second Edition

The attached file (PDF) has some guidance about notable changes in the Highway Capacity Manual 2010 - particularly about Freeways, Multilane Highways and Two Lane HighwaysHCM2010-Update.pdf

Very nice. Thanks c_n.

civilized_naah said:

The attached file (PDF) has some guidance about notable changes in the Highway Capacity Manual 2010 - particularly about Freeways, Multilane Highways and Two Lane Highways

HCM2010-Update.pdf

Click to expand...

Thanks!

The PHF was changed to 0.94, is this for urban or rural (both?)

Thank you.

John Q said:

The PHF was changed to 0.94, is this for urban or rural (both?)

Thank you.

Click to expand...

I think neither. See page 10-11 Chapt 10 Vol 2.

Assumptions for urban freeways:

• Total ramp density= 3.00 ramps/mi (i.e., 1/3-mi average spacing between ramps);

• 5% trucks, no recreational vehicles (RVs), and no buses;

• PHF = 0.95; and

• fp= 1.00.

Assumptions for rural freeways:

• Total ramp density= 0.20 ramp/mi (i.e., 5-mi average spacing between ramps);

• 12% trucks, no RVs, and no buses;

• PHF = 0.88; and

• fp = 0.85.

Now I am confused, I am only going off the errata sheet posted above. I have not bought the 2010 HCM yet, obviously the HCM is correct.

Page 747 (All In One): PHF = 0.88 (rural), 0.92 (urban)

Errata sheet above states: "The default value of PHF is changed to 0.94 .... "

This isn't mission critical, I'm not going to make the cut for April 2014, so I have until October.

Me too! Chapt 11, pg 11-21 HCM2010 lists PHF=0.94 as default (see below). Perhaps Dr. G. can clarify?

[sorry, all the formatting was lost]

In using this chapter's methodology, a range of input data is needed. Most of

these data should be field-measured or estimated values for the specific segment

under consideration. When some of the data are not available, default values

may be used. However, the use of default values will affect the accuracy of the

output. Exhibit 11-16 shows the data that are required to conduct an operational

analysis and the recommended default values when site-specific data are

unavailable (13).

Required Data Default Values

Geometric Data

Number of lanes in one direction

Lane width (ft)

Right-side lateral clearance (ft)

Ramp density (ramps/mi)

Terrain or specific grade (%, length)

FFS (mi/h)

No default, must have site-specific value

12ft

10ft

No default, must have site-specific value

No default, must have site-specific value

Urban, 70 mi/h; rural, 75 mi/h

Demand Data

Length of analysis period (min) 15 min

PHF 0.94

Proportion of heavy vehicles (%) Urban, 5%; rural, 12%*

Driver population factor 1.00

* Alternative state-specific default values for percentage of heavy vehides are given in Chapter 26.