**Problem 6: Planning
Level Analysis **

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Thus far, we have
taken an operational perspective in our analysis. Occasionally, when we are
considering future conditions, we are better served by looking at a less
detailed level of analysis, often called a planning level analysis. Let's
take this planning perspective now, considering the twenty-year traffic
projections. All of the intersections on U.S. 95 will be examined to assess
their sufficiency at the end of the twenty-year period. The signalized
intersection quick estimation procedures contained in Appendix A to
Chapter 10 of the HCM 2000 will be applied for this purpose.

The question to
consider now is whether or not the number of lanes at the U.S. 95/Styner-Lauder Avenue intersection will be sufficient to accommodate the
projected traffic demand over the twenty-year planning horizon. A uniform
increase of two-percent per year will be applied to the current volumes on
all traffic movements. Compounded annually, the two-percent annual
increase will produce a growth factor of 48.6% to apply to the current
volumes.

The quick
estimation method covers all aspects of signalized intersection analysis,
including determination of left-turn treatments, lane-volume computations,
estimation of signal timing plans, calculation of the critical
v/c ratio, and
calculation of average
control delay. The delay calculations use the same
mathematical procedures as the operational analysis method, except that
certain details, such as pedestrian minimum times, are excluded from
consideration. Liberal use is made of assumptions and approximations.

This method is
well suited to analysis of conditions projected over the long term where the
accuracy of the traffic volumes is questionable and immediate implementation
of results is not an issue. The method will be applied to each of the
intersections on U.S. 95 in separate sub-problems:

Sub-problem 6a: Planning
Analysis at Palouse River Drive

Sub-problem 6b: Planning
Analysis at Styner-Lauder Avenue

Sub-problem 6c: Planning Analysis at Sweet Avenue

Sub-problem 6d: Planning Analysis at SH-8