7.0 Final Report and Technical Documentation

This chapter discusses the suggested documentation of the CORSIM analysis in a final report with supporting technical documentation.  The effort involved in summarization of the results should not be underestimated, since CORSIM produces a wealth of numerical output that must be tabulated and summarized.  The list of suggested deliverables was established in the scope of the project in Chapter 1.  If documentation was developed and refined throughout the analysis according to the scope laid out in Chapter 1, the final step may be as simple as collecting and delivering the appropriate documents. 

The report form will depend on factors such as the reviewing agency’s guidelines, the size and complexity of the analysis, and consensus on the final deliverables before beginning the analysis.  One possible way to structure the final deliverables is to create two separate documents, a final report and a technical report.  This may only be necessary for larger projects while for smaller projects the final report and technical documentation may be provided in one report.  The key is that the results must meet the needs of two audiences: the non-technical decision makers and the technical specialists responsible for technical reviews.  The suggested format that follows may be useful regardless of whether the final documentation is presented in one report or divided into two reports.

7.1 Final Report

The final report presents the analytical steps, assumptions, and results of the analysis in sufficient detail for decision makers to understand the basis for and implications of choosing among the project alternatives.  The final report should include the following:

1. Study objectives and scope.
2. Overview of study approach (tools used, methodology, rationale).
3. Data collection (sources and methods).
4. High level model description, diagrams, assumptions, and modifications.
5. Demand forecast assumptions (assumed growth inside and outside of the study area, street improvements, variations to support a sensitivity analysis, etc.)
6. Description of alternatives and modifications (improvements).
7. Discussion of success or failure of design/alternatives.
8. Results and recommendations.

The benefits and implications of alternatives should be presented in the final report, preferably in layman terms.  Using the output data, summarizing it, and converting it to decision support intelligence should make it very clear what decisions are recommended. 

7.2 Technical Report

The technical report plus appendices should document the CORSIM analysis in sufficient detail, including the version of the software used, to enable an analyst to understand the calibration process, repeat the alternatives analysis, and reproduce the results.  The technical report may be an appendix to the final report or a separate document.  The technical report is a vital step in preserving the rationale for the various decisions that were made in the process of developing, calibrating, and operating the CORSIM model.  Due to the stochastic nature of simulation models, the high probability of errors in model coding, and incorrect judgment, these models must “hold up” to scrutiny.

The technical report should typically be submitted with both electronic data and hard copy printouts of project drawings and narrative descriptions of the material provided.  The technical report should include the model input, data collection and field observations, calibration adjustments, model results, and output files (in electronic format) for the final model calibration run and alternatives analysis model runs.  In addition to the electronic format, the technical report should include a printed listing of the files with a text description of the contents and purpose of each file.  Each step in the analysis should be documented and should include:

1. Study Objectives and Scope.
2. Data Collection.

• Input Data.
  • Link-node diagrams for all alternatives.
  • Plan sheets of the link-node diagrams.
  • Lane schematics.
• Traffic demand data.
  • Arterial turning movement counts - raw and balanced.
  • Freeway mainline and ramp traffic volumes.
  • Traffic count reconciliation process and results.
  • Balanced traffic count dataset.
  • Origin-destination matrix calculations (if necessary).
• Traffic control data.
  • Ramp metering rates and timing data.
  • Signal timing data from signal controller printouts and field observations.
• Transit, pedestrian, bicyclist, or other relevant data.
• Traffic operations and management data (ITS devices and locations, traveler information sources, etc.)
• Field observations (video, pictures, sketches, or notes).

3. Model Development.

• Model assumptions.
• QA/QC process and results.
• Coding techniques for complex or unconventional geometrics or operations.

4. Error Checking.

• Error checking process and results.
• 100% coded model.

5. Calibration.

• Calibration process, tests, and results (which parameters were modified and why).

6. Alternative analysis.

• Sensitivity analysis.
• MOE report on a spatial and temporal scale to show how the MOEs change throughout the analysis period and study area.
• Final results and recommendations.
• Output data (electronic files).
  • CORSIM TRF files.
  • TRAFED TNO files.
  • Background image files.
  • MOE files.
  • Configuration files for MOE multi-run data.
  • Signal optimization tool files.
  • CADD files.

7.2.1 Technical Memorandums

Technical memorandums are intermediate reports of technical issues pertaining to the model during the course of the project.  These memos are usually defined during the project scoping process; however, during the project, the need to elaborate on a particular issue may be necessary.  Below are some of the intermediate tech memos that may need to be prepared.

• Traffic Demand Forecast Methodology and Results.  Future year demand forecasts are a critical factor in the alternatives analysis, and thus the forecasts need to be clearly documented and agreed to by all parties involved before beginning the modeling process.  This memorandum can be incorporated into the final documentation.
• Intermediate Modeling Issues.  During the modeling process, unusual or complex issues or problems may arise where an unconventional modeling approach may be required.  This may require documentation to record the problem and potential solutions.  Discussions with software technical support personnel may also be needed.  Any such modeling issues could be documented in a memo, discussed, and a satisfactory approach should be agreed upon before beginning the alternatives analysis.
• Model Calibration.  A well-calibrated model is crucial to a sound analysis of alternatives, and thus the calibration needs to be clearly documented and agreed to by all parties involved before beginning the alternatives analysis.  This memo would document the process and resulting changes made to the model related to calibration.  The memo would also provide justification for any model changes and supportive statistics of comparisons between observed and modeled MOEs.
• MOE Summary Report.  The interim results of an alternatives analysis may be summarized in a memo that contains the MOEs for the alternatives tested.  Such a memo would give the reviewing agencies a chance to review and comment on the results before the final report is prepared and the analysis is complete.  The report should present the MOEs on a spatial and temporal scale to show how the MOEs change throughout the analysis period and study area. 

7.3 Presentation of a CORSIM Simulation Analysis

The presentation of the CORSIM analysis is very important to the possible acceptance or rejection of the recommendations of the analysis.  CORSIM can produce such a large quantity of data that it can become overwhelming to decision makers.  The data must be reduced by using drawings, graphics, animation, and summary data tables.  Decision makers may be skeptical of the methods used to produce the data.  The presenter must be prepared to defend the analysis methods.

Animation of simulation runs representing current conditions and various alternatives is a very effective way to display the traffic operations to decision makers and, in particular, to point out deficiencies, or unacceptable operations, within the alternatives.  The animation should focus on areas that show the advantages and disadvantages of the alternatives.  A particularly difficult issue is in choosing which simulation run to show an animation, as it is not possible to animate the mean values of all MOEs.  The analyst must choose an individual run that demonstrates a representative run of the MOEs of interest.  The analyst must also determine if they want to animate the worst case, best case, or mean case of the MOEs of interest.  The “Reviewing Animation Output” discussion in section 6.6 contains important information on how to select a representative run when presenting an animation.

7.4 Example Problem: Final Report

Example: Returning to the example problem for HWY 100, a final report was prepared for presentation to the client.  The format for this document was one final report with appendices providing the technical output of the preferred alternative.  The final report follows the model development and application process outlined in this document.  The report begins with a brief executive summary that provides a project overview.  Then, details of data collection, model development and calibration are provided before moving into the alternatives analysis discussion.  The report thoroughly explains the alternatives and provides graphics and spreadsheets to easily compare output data.  The report also addresses the preferred alternative, providing graphics and spreadsheets to support the conclusions.