U.S. Department of Transportation
Federal Highway Administration
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
|This report is an archived publication and may contain dated technical, contact, and link information|
|Publication Number: FHWA-HRT-11-064 Date: November 2011|
Publication Number: FHWA-HRT-11-064
Date: November 2011
This appendix describes a few useful references on the application of traffic analysis tools.
The FHWA's Traffic Analysis Tools Program Web site provides a comprehensive set of resource documents for selecting and applying traffic analysis tools.(1) The site can be found at http://ops.fhwa.dot.gov/trafficanalysistools/index.htm.
The first two volumes are particularly useful for selecting among traffic analysis tool types. The volumes are as follows:
Volume V of the FHWA's Traffic Analysis Tools Program includes a brief case study of an application of sketch planning for interchange analysis in Eugene, OR. The FHWA Decision Support Methodology spreadsheet identifies a number of sketch planning tools. Section 3.1 of the British Department of Transport's Web-based Transport Analysis Guides provides a description of spatially aggregate models and specifies when these should be used.(11)
The FHWA has created the Travel Demand Modeling Improvement Program to support good practices in travel demand modeling. The resources Web page provides recommended reading, technical references, and a clearinghouse of documents on travel demand modeling and can be found at http://tmip.fhwa.dot.gov/.(12)
The introductory sections to each of the methodological chapters in volumes 2 and 3 of the 2010 HCM list the limitations of the methodologies described in the manual.(8) Chapter 6 in volume 1 directly addresses traffic analysis tools with descriptions of tools, guidance on the selection of tools, and guidance on their use. Chapter 7 addresses the presentation and interpretation of results with specific guidance on addressing uncertainty in the interpretation of analysis.
The HCM applications guide, located in the volume 4 technical reference library of the 2010 HCM details case studies that cover the fundamental applications of various methodologies. The applications guide is directed toward new users of the manual.
Volumes III and IV of the FHWA's Traffic Analysis Tools Program provide guidance on the development, calibration, and validation of microsimulation models. Volumes I and II of the same toolbox series provide guidance on the selection of microsimulation.(1)
The Minnesota Department of Transportation relies on CORSIM for most of its corridor studies and has developed a CORSIM modeling and calibration guideline based on the FHWA simulation modeling steps.(13) Prior to modeling, the guideline provides tips for scoping the project and whether or not a CORSIM analysis is appropriate. The second part of the guideline discusses base case modeling techniques, calibration, and alternatives analysis. Support beyond this guideline is also available online, where past projects, sample tables, and screenshots as well as CORSIM input files are available.
The Oregon Department of Transportation (ODOT) developed a traffic simulation guideline for four of its most commonly used software packages, including SimTraffic, VISSIM, PARAMICS, and CORSIM.(14) The SimTraffic guideline is by far the most thorough of all four, discussing topics including data recommendations, default values, common parameters, and data outputs. ODOT requires that VISSIM/PARAMICS submittals (i.e., volumes, signal timings) from consultants be converted to Synchro for more effective review.
The final report for NCHRP 3-85, Guidance for the Use of Alternative Traffic Analysis Tools in Highway Capacity Analyses, provides guidance on the selection and use of alternative traffic analysis tools to the HCM.(9) The report reviews how level of service is derived from simulation model outputs and the appropriateness of doing so. It develops methods for translating MOEs between different analysis tools and develops guidelines for the use of DTA tools.
The Ministry of Transport has sponsored a Web-based Transport Analysis Guide that provides general guidelines for the conduct of transport studies.(11) Section 2 is directed toward project managers and is very broad in scope. This guidance addresses the scoping of analysis, stakeholder participation strategies, and policy options and strategies as well as a framework for cost-benefit analysis and summaries of a variety of modeling applications. Section 3 is addressed to experts and provides a more detailed overview of the appropriate stages of analysis as well as input and policy output requirements. Methodologies are addressed at the level of theory. References to other more detailed documentation are included throughout.
Transport for London has issued guidelines for transport assessments required of major developments under its planning authority.(15) This includes a review of the criteria used for requiring assessments. The specific guidance addresses scoping, study and report organization, and recommended methodological approaches.
Austroads prepared a research report that explores the limitations of microsimulation traffic models and provides a list of appropriate problems amenable to microsimulation analysis.(16) Furthermore, the report provides some background on a variety of microsimulation software packages and reviews criteria for selecting among these. The report addresses good practices for model validation and calibration. The report includes a pro forma for the formalized auditing of microsimulation models. The report is also appended by guidance on the scoping of microsimulation analysis under the heading "Preparing a Brief for Microsimulation."
A draft report from the Japanese Society of Traffic Engineers provides an overview of the microsimulation modeling process, discusses appropriate applications for microsimulation, and reviews model verification techniques.(17) The paper makes a distinction between verification and validation, indicating that the first is a process of evaluating the reproducibility of theoretical results with model results based on virtual data sets whereas the latter deals with the reproducibility of observed travel characteristics using actual data. The paper discusses verification and validation in detail.