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Sub-problem 1c - Page 5 of 5

ID# C401C05

Sub-problem 1c: Analysis of the Eastbound Freeway Section

We can close out this analysis by looking at the performance of this facility across the entire year. As was the case for the eastbound analysis, we have data for 256 hours during 2001. The histogram, in Exhibit 4-15, shows that the predominant LOS is C, with some evidence of D, E, A, and B. It’s clear that you can describe the LOS of this westbound section as being predominantly C under the conditions we assumed: 5% trucks/buses, 0% recreational vehicles, and 0% daily users. If one or more of these assumptions change, the situation could be different.

To explore how different it might be, we changed just one variable, the assumption about daily users. We did this because during the spring, summer, and fall months many of the users on Friday afternoons are vacationers. If we change this assumption, the value of fP can range as low as 0.85. The results of this analysis are presented below in Exhibit 4-16.

Exhibit 4-16. Driver Familiarity Adjustment
LOS MaxD Reg Drive Vacation
NHr Pct NHr Pct
A 11 8 3.1% 7 2.7%
B 18 7 2.7% 2 0.8%
C 26 195 76.2% 20 7.8%
D 35 37 14.5% 210 82.0%
E 45 4 1.6% 11 4.3%
F >45 5 2.0% 6 2.3%

The percentage of hours at LOS F doesn’t change that much, from 2.0% to 2.3%, but the predominant LOS changes substantially, from C to D. Now 82% of the time, the LOS is D while only 7.8% of the time it is C.

Neither one of the situations, either “Regular Drivers” or “Vacation” drivers exactly describes peak hour situation. The truth is somewhere between. However, what we can say is that the LOS is typically either C or D. Moreover, it’s C-like during normal peak hours when the regular drivers predominate, and it’s D-like when the vacation drivers are present.

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