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32 CONCLUSIONS AND FURTHER RESEARCH NEEDS ridership forecasting techniques and are increasing the confidence level in forecasting results. There will always Qualitative forecasting techniques relying on profes- be a role for professional judgment and experience, par- sional judgment and experience continue to be widely ticularly in understanding the underlying factors affect- used by transit agencies, especially for small-scale and ing ridership behavior. The continued integration of rid- near-term changes. Some consider these too subjective ership, service, demographic, and other data will provide and too dependent on the skill of the analyst. Examples new tools to assist in this understanding. cited throughout this synthesis demonstrate that "qual- itative" does not equal "simplistic." Qualitative proce- Findings from this synthesis suggest five major research dures can involve consideration of a wide variety of needs: factors, often geared toward identifying similar cir- cumstances elsewhere in the transit system that can 1. Transferability of ridership forecasting methodologies. provide guidance for likely ridership response. How well does a methodology developed at one transit Use of service and headway elasticities is widespread agency work at another agency? Calibration to local con- among transit agencies. Broad-based studies such as ditions is a given; however, how extensive is the needed TCRP Report 95 are very useful in providing informa- calibration and how accurate are the resulting forecasts? tion on "typical" elasticities; however, several agencies Ongoing work with the T-BEST model in Florida, spon- have emphasized the need to adapt these to their service sored by the Florida Department of Transportation, has areas using their own experiences. as one of its purposes calibration and use of this model Formal travel modeling expertise is found at the MPO, at all transit agencies within the state, and should offer not usually at the transit agency. The literature review interesting findings regarding transferability. noted that several MPOs are actively engaged in the 2. GIS applications in ridership forecasting. The use of development of forecasting methodologies at a more GIS by transit agencies continues to increase. appropriate scale for transit needs than the traditional Although many GIS applications are oriented toward four-step travel model. At the same time, widespread simple mapping functions, the true value of GIS in use of new technologies such as GIS and APCs allow transit may be as a data integration platform that sim- transit agencies to develop more sophisticated ridership plifies data management. Additional research in this forecasting tools. These developments suggest the pos- area should have a positive return. sibility of convergence in the near future. 3. Easy-to-use methodologies. As previous experience Transit agencies reported that a strong, ongoing work- has shown, forecasting procedures relying on data that ing relationship with their MPOs is beneficial to both are not readily available to transit agencies are unlikely parties. Modelers and transit planners often work in dif- to be used. User acceptance should be a primary focus ferent time frames and geographic scales, and ongoing of future research efforts in this field. communication helps to bridge these gaps. The New 4. Implementation of new technologies. Transit agen- York City case study findings emphasize the benefits of cies in the process of acquiring APC systems antici- interaction between modelers and planners within large pate that the use of APCs will solve problems with transit agencies. the availability of ridership data at the route segment Transit agencies reported value in ridership forecasting or stop level. However, APC implementation has not methodologies. Several noted that ridership forecasts always been successful. Several agencies, including provide a basis for prioritizing among competing pro- VIA and OCTA among the case studies, have expe- posals and, more generally, for decision making at the rienced problems in obtaining usable data from senior management and board levels. Internally, rider- APCs and/or in convincing all departments within ship forecasting can encourage discipline in the service the agency that APC data are equally or more reli- planning process, particularly where there is ongoing able than farebox or manually collected data. Other interaction between modelers and service planners. agencies, including RTD and TriMet among the case This interaction can also result in improved method- studies, are very confident in and rely extensively on ologies. Sound ridership forecasting methodologies their APC data. Future research into factors affect- can also enhance a transit agency's credibility among ing successful implementation would be useful not stakeholders and peer local and regional agencies. only in relation to APCs but also for the variety of Does the state of the art in transit ridership forecasting ITS applications that will come on line in the near justify the high value that transit agencies place on this future. function? At many agencies, forecasting is more of an art 5. The need for cost-effective and reliable data collection than a science and is likely to remain so in the near future. efforts. Quality and availability of input data continue However, new technologies that provide more accurate to be among the primary concerns of transit agencies. ridership data and enhance the ability to summarize Research geared toward reliable data collection at the demographic and socioeconomic data at an appropriate appropriate level and at an affordable price could have level of detail are fostering continued development of enormous practical value.