Estimating Revenues Using a Toll Viability Screening Tool

As the proportion of highway needs that can be supported by fuel taxes declines, the attractiveness of toll funding rises. Public agencies and local authorities are examining their options and some states, notably Texas, have broadly increased the range of local toll-related options available. These entities need an analytical tool that will allow them to make realistic "first-cut screening" estimates at potential revenue, so they can make prudent determinations about the potential viability of a toll-supported option. Most of the variables associated with revenue prediction are highly variable - corridor demand, diversion rate, and acceptable tolls. Sometimes only point estimates of these variables are available. But, it is imprudent to treat these factors as point estimates for simplicity of analysis, because such estimates can easily mask either a truly viable project or clearly questionable project. This report documents the development of a spreadsheet analysis tool to provide a preliminary determination of the viability of a toll road or toll-supported project. The tool uses inputs typically available to TxDOT or local planning agencies and outputs measures representing various aspects of viability including economic measures, such as annual revenue or net present value. The project treats input and outputs as random variables, uses sensitivity analyses to identify critical variables, and develops probability distributions that improve the accuracy, reliability, and decision-making value of the toll study. The results of this project provide to TxDOT and local agencies a "first-cut screening tool" to be supplemented by investment-grade traffic and revenue studies if the findings warrant.