Sub-problem 1b: Analysis of the Proposed Signalized Intersection

Let's discuss each of these issues and how each affects the operational analysis that we are about to complete.

Which tool or tools should be used for this analysis? There are a number of tools that the analyst might consider to solve this problem. A hand-calculated critical movement analysis or the HCM planning analysis might be considered to get a quick assessment of the intersection performance and operation. These are both discussed at greater length in Problem 6 in this case study. Other non-HCM tools such as Synchro, CORSIM, or aaSIDRA might be used. Finally, the HCM operational analysis method for signalized intersections, which produces estimates of control delay, v/c ratio, and queue length, is a potential tool for this sub-problem. We will use this latter tool for this analysis. Why did we make this choice? When we are considering conditions in which demand does not exceed capacity, or the flows from one intersection do not spill back and affect the adjacent upstream intersection, the HCM operational analysis method provides a useful and easily applied tool. In addition, we are conducting a comparative analysis between signalized and unsignalized intersection operational characteristics, so we are looking for procedures that allow this kind of comparison to be made easily and consistently. We will explore the use of non-HCM tools in problems 3 and 4 of this case study. We will address some of the major issues that are often confronted by analysts using the HCM methodology in this and subsequent problems in this case study.

The analysis tools for signalized intersections are contained in chapter 16 of the HCM 2000. The computational methodologies included in this chapter are complex and cover a wide range of conditions that are often observed in the field.