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Getting Started
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Getting Started - Page 2 of 5

ID# C1GS002

Getting Started

The Idaho Transportation Department has primary authority for the operation of U.S. 95. It does all of the planning, design, and maintenance of this highway. However, it works closely with the staff from the City of Moscow so that, as much as possible, decisions regarding the state highway facilities within city limits are made jointly between the city and the state. As we develop the results from our analyses, the major audience, then, will be the engineering staffs from these two agencies. 

In addition, residents of the city will need to understand the rationale for any final decision that is made regarding the intersection and whether a signal should be installed or not. This points up an important issue in any technical analysis. While any analysis must be technically sound and based on standard methods of professional practice, it must also be presented in such a way that it is understandable by decision makers and elected officials (who often do not have technical backgrounds) as well as the general public. This is particularly important as we consider such concepts as level of service, and as we talk about sensitivity analysis and the relative certainty that we have in our final results.

The major reason for conducting the analyses that makes up this case study is to provide decision makers with sufficient information about the performance of the intersection of U.S. 95/Styner Avenue/Lauder Avenue so that they can decide whether the intersection should be signalized or whether it should remain stop-sign controlled. The Highway Capacity Manual provides estimates of delay, volume/capacity ratio, queue length, and other data that are helpful to decision-makers in making this kind of decision.

We should also point out that the Manual on Uniform Traffic Control Devices (MUTCD) is commonly used to determine if a signal is warranted and in most jurisdictions is the legal document used to determine many of the characteristics of a design. However, it is also useful to compare the forecasted operations of an intersection under different control scenarios. The Highway Capacity Manual provides the tools for such an operational analysis.

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