The ITS Costs Database contains three types of entries: system cost summaries, cost element ranges, and sample unit costs. System cost summaries are useful to understand real-world examples of full system installations, but do not always provide an itemized breakdown of costs. Cost element ranges may be useful for estimating costs of specific equipment purchases since they have been compiled with many years’ worth of data using expert judgment. Sample unit costs may be useful to the user who wants to review individual cost entries and construct a custom cost estimate.