27 CAR § 95-406 – Select an operational analysis tool

(a)
1. (1) There are many traffic operational analysis tools available for different situations.
2. (2) These can include deterministic tools such as the Highway Capacity Software based on the Highway Capacity Manual (HCM), or stochastic microsimulation tools such as VISSIM.
(b)
1. (1) It is widely understood that in many situations around freeway interchanges, particularly in urban areas, the HCM methodology alone is not likely sufficient for appropriate analysis.
2. (2) To obtain meaningful results from the operational analysis, having a clear understanding of the context for analysis is vital to the selection of the appropriate analysis tool.
3. (3) Answering the questions identified in Figure 4 about the context for the analysis will assist in defining the needs and requirements of the analysis tool.
(c) It is the responsibility of the proposing entity to make this selection, which should be discussed during early coordination.
(d) Guidance for selecting appropriate tools can be found in the Federal Highway Administration Traffic Analysis Toolbox. Source: Traffic Analysis Toolbox Volume II: Decision Support Methodology for Selecting Traffic Analysis Tools, January 2007 Figure 4. Decision Support Methodology for Selecting Traffic Analysis Tools
(e)
1. (1) Regardless of which tool or tools is selected, it is not only important to understand the limitations of the chosen tool or tools, it is also essential to apply the tool or tools in a manner which supports a verifiable, reproducible, and accurate analysis.
2. (2) This includes the effective calibration of the chosen tools and proper interpretation of the output.
(f)
1. (1) Figure 5 presents a process for the application of a microsimulation tool.
2. (2) While developed for microsimulation, the overall framework may be used to support any traffic analysis, regardless of tool type.