use of elasticities in a properly tailored framework could take into account direct and indirect relationships between different modes. In addition, the use of cross elasticities assures taking into account substitution and complementary effects among transportation alternatives.
Finally, the use of the pivot-point logit equation precludes the distinction between short run and long run effects. The parameters that influence modal shares are the byproduct of cross-sectional analyses (unless specified otherwise) which do not take into account the long-run adjustments those users inevitably face. The use of a model based on transport elasticities could provide a method that differentiates between a program’s short and long run impacts.
International Evaluation Procedures
The literature review extended to cover models and approaches followed internationally, with a focus on predictive evaluation methods.
European efforts are concentrated on monitoring and evaluation, as distinct from projection and estimation, with the biggest effort represented by the Mobility Management Strategies for the Next Decades (MOST). This project, sponsored by the European Commission until 2002, was intended to provide an insight on policy frameworks and implementation strategies, as well as an investigation of setting up standardized monitoring and evaluation tools. The literature review did not encounter examples of predictive evaluations in Europe. Given the MOST project objectives and
focus on monitoring and implementation, a full review of its structure and
conclusions published a
research effort summarizing European experiences in the field of TDM.
The bulk of international, non-European experience is reflected in the Australian and New Zealand efforts to develop predictive TDM evaluation procedures[5, 6].
In Australia and New Zealand most of the TDM measures fall under the definition of Travel Behavior Change (TBhC) strategies. TBhC embraces a subset of TDM measures mostly centered on marketing approaches designed to build awareness in SOV users about alternative modes of transports or to promote voluntary mode change. TBhC measures include:
Workplace based initiatives (carpooling, vanpooling)
School travel initiatives
2 Note: the Transfund literature review reported the unavailability of examples of predictive evaluations in UK and Europe or any established TDM evaluation procedures.