This paper describes the development and application of a national multimodal county level model for long-distance travel forecasting. The model was developed for use in a study of the feasibility of extending the South Central High Speed Rail Corridor from Little Rock, AR to Memphis, TN.

Traditionally, long-distance intercity travel is not as well studied as intra-city travel and is typically not represented in most passenger models. Standard passenger models, either include long distance trips in an external trip purpose or in some cases completely ignore long distance trips.

Long distance trips that are considered are typically not tracked once they leave the model area. Therefore, existing tools for studying long distance travel – which is essential in the feasibility analysis of a rail project traversing several states and connecting to existing long distance rail routes – are far from satisfying. By developing a national county level model, long distance travel can be estimated within a system that includes information on both ends of the trips. This makes possible the comparison of multiple rail alternatives connecting to the existing AMTRAK system at various cities and makes possible an understanding of the nature and size of various travel markets.

Investigators developed base year and forecast year county level demographics data (population, household, and employment, etc.) and model networks (highway, air, passenger rail, intercity bus and urban rail) from national data sources. Alliance estimated long distance travel characteristics from national travel surveys (2009 NHTS, 1995 ATS). Then the model was validated to available ridership data (FAA 10% sample, AMTRAK OD data, Arkansas state level bus ridership) and applied for the subsequent high speed rail feasibility study.

The model proved to be a useful system level planning tool for forecasting intercity travel demand and conducting a feasibility analysis for intercity transit services (intercity bus, rail, and air etc.).