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Sub-problem 5a - Page 2 of 3

ID# C105A02

Sub-problem 5a: Existing Analysis of 10-Mile Segment of U.S. 95

Step 2: Setup

What data are required for the analysis? We want to determine the LOS that drivers experience on the existing 10-mile section. The analysis methodology contained in Chapter 20 of the HCM is applicable, and the following data are needed to conduct an operational analysis:


geometric data


demand volumes for each direction


free flow speed

Today, the average daily traffic on U.S. 95 is about 600 vehicles per hour (both directions). Insofar as the input parameters are concerned, we’ve found from field studies that the shoulder widths are 6 feet, the lane widths are 12 feet, and the directional split is 54% southbound/46% northbound, consistent with the southbound side of the Styner-Lauder intersection that serves as the northern border of this corridor. The peak hour factor (PHF) is set to the HCM-recommended default value of 0.88, the percentage of trucks and buses is 10%, and there are no recreational vehicles. The base free-flow speed is 60 mph, the percent no-passing zones is 30% and there is an average of 2 access points per mile (an access point is a street, a driveway, or a curb cut that is significant in terms of traffic operations.)

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