Transit Ridership Forecast Methods. There were no national studies which focused on technical modeling guidelines until 2006, when the TCRP Synthesis 66 provided a comprehensive overview of fixed route transit ridership forecast practices throughout the United States through literature review, surveys and telephone interviews. Seven major techniques were recognized for transit ridership estimation, and most agencies used multiple methods. • Professional judgement • Rules of thumb/similar routes • Service elasticities • Four-step demand model • Econometric model • Regression analysis • Other methods – include trend line analysis, ITE trip generation rates, etc. While the report did not delve into the analytical details, it provided a clear picture in terms of the purpose of ridership forecast, the methodologies, data sources, the planning horizon. Some of the major findings from the report included: • Qualitative forecasting techniques were still widely used by transit agencies, especially for small-scale and near-term changes. They highly relied on professional judgment and experience. However, these methods could not be considered simplistic by any means as they tended to involve consideration of a wide variety of factors, often geared toward identifying similar circumstances elsewhere in the transit system that could provide guidance for likely ridership responses. • The use of service and headway elasticities was widespread among transit agencies. In view of this, TCRP Report 95 were very useful in providing information on “typical” elasticities; however, several agencies desired to adapt these to their service areas using their own experiences. • Formal travel modeling expertise was found at the MPOs, not usually at the transit agencies. The literature review noted that several MPOs were actively engaged in the development of forecasting methodologies at a more appropriate scale for transit needs than the traditional four-step travel model, including Georgia, Arizona, Texas, and Tennessee, where sketch planning tools were developed. • Widespread use of new technologies such as Geographical Information System (GIS) and Automatic Passenger Counts (APCs) were expected to allow transit agencies to develop more sophisticated ridership forecasting tools. • Transit agencies reported the value in ridership forecasting. Several noted that ridership forecasts provided a basis for prioritizing among competing proposals and, more generally, for decision making at the senior management and board leve...
