Cost data come from a variety of sources ranging from detailed transportation agency bid tabulation data to high-level project data presented in deployment reports. Sources are analyzed and if deemed applicable can serve as a new cost entry in one or more parts of the ITS Costs Database. 

• System cost summaries are taken primarily from written sources such as formal evaluation reports, conference papers and presentations, data from State and local DOTs, and self-reported costs from recipients of ITS Program funds. On occasion these sources are supplemented with correspondence with the reporting agency or organization. Specific sources are cited with links to source documents when available.
• Cost element ranges are based on several cost estimation efforts developed for the U.S. Department of Transportation (U.S. DOT) ITS Joint Program Office (ITS JPO) and have been updated based on new data sources such as ITS project evaluations, State and local DOT ITS deployment reports, vendors of ITS products, and self-reported costs from recipients of ITS Program funds. Analysts review and analyze available cost data, then update the unit costs ranges (low to high) when appropriate. If no data are available for a unit cost element, then the value remains unchanged. A chronological listing of direct and indirect sources is available at Data Sources.
• A sample unit cost source may contain cost data that are used to update the values in the cost element ranges. See About Costs for the relationship of cost sources and the three types of costs data.