Documentation standards in project-level traffic forecasting
Go to the Project-level traffic forecasting topic page.
Project-level forecasts must be accompanied with a document that describes how the forecast was accomplished. The document should be written in memorandum form. The document should describe these items:
- Project description, including the environmental setting, surrounding land uses, potentially impacted transportation facilities, and the anticipated open-to-traffic date;
- Project alternatives, including the do-nothing alternative;
- Elements of the forecasting process, including a list of techniques and models employed;
- Special requirements;
- Types and sources of data, including descriptions of networks;
- Methods used to process data;
- Sources of parameters;
- Base and forecast years;
- Time period of analysis;
- Problems encountered and assumptions;
- Scenarios;
- Direct results (volumes and speeds);
- Results of any other post-processing;
- An assessment of the level of confidence in any estimate; and
- Name and affiliation of preparer, date of preparation.
The document should be well written and sufficiently attractive for presentation at a public meeting. The document should contain a list of preparers and their affiliations, if there is more than one preparer. The document should be signed by the person responsible. Optionally, the documentation may contain a glossary or list of acronyms. An appendix should include the traffic forecast request form, as submitted.
The documentation shall be professional, “objective, impartial and impersonal” (Oregon’s “Traffic Analysis Manual”).
The report should contain maps and illustrations, such as:
- Study area map and boundaries;
- Map of surrounding highway system;
- Map of surrounding land use;
- Map showing any new site developments;
- Picture of the forecasting network, if any;
- Traffic volumes on roads;
- Turning movements at intersections;
- Details of project geometry for all alternatives, to the extent that they affect the forecast; and
- Details of traffic control elements for all alternatives, to the extent that they affect the forecast.
Forecasted traffic volumes, traffic speeds and other outputs should be presented in tabular form, where possible.