Validation of aggregate reference forecasts for passenger transport

We have compared Swedish national forecasts for passenger transport produced from 1975 to 2009 with the actual outcomes, and we found substantial differences between forecasts of passenger kilometers by mode and actual outcomes. In forecasts produced since the early 1990 s, road and air traffic growth rates have generally been overpredicted. Aggregate railway growth has been fairly accurate, but commercial long-distance railway growth has been overpredicted, and the growth of subsidized intra-regional railway travel has been underpredicted (following vast unanticipated supply increases). Focusing on car traffic forecasts, we show that a very large share of forecast errors can be explained by input variables turning out to be different than what was assumed in the forecasts. Even the original forecasts are much closer to actual outcomes than simple trendlines would have been, and once the input assumptions are corrected, the forecasts vastly outperform simple trendlines. The potential problems of using cross-sectional models for forecasting intertemporal changes thus seem to be limited. This tentative conclusion is also supported by the finding that elasticities from the cross-sectional models are consistent with those from a time-series model.QC 20170207</p

Predicting the results of a referendum on urban road pricing in France : "the cry of Cassandra"?

Introduction Abundant literature now exists on the acceptability of the new pricing measure represented by urban tolls. However, this literature contains few examples providing a "political" analysis of their introduction. Here, our aim is to study how the political behavior of individuals, identified on the basis of general attitudes regarding the principles of regulation and pricing, influences, or does not influence, attitudes with respect to urban tolls. Method We study the ex-ante determinants of a vote on urban tolls. We use the results of a survey performed in France in the framework of the European Project ExpAcc (Explanatory Factors of Road User Charging Acceptability). We process the data using a Principal Components Analysis (PCA) then perform ordered logit estimation. Result Regarding the specific question to the referendum, we show that it would be rejected by electors. We also show that there is a significant link between general attitudes to regulation by legislation, tax or pricing policies in transport on the one hand, and the vote in the referendum on tolls on the other. We confirm that individual self-interest matters a lot in political behaviour but that other types of motives also matter strongly Conclusion As a consequence, a real-life political analysis cannot be limited to classical "economic" variables, even if they matter too obviously. Lastly, our results should be placed in relation with those concerning the more global issue of the acceptability of a new pricing measure through, for example, that of the compensation to be implemented.QC 20160715This project received funding from Predit 3 in the framework of Era-net SURPRICE.</p

Implementation of pedestrian meso models in Portugal

VRU-TOO; Vulnerable Road User Traffic Observation and Optimisation; Deliverable 8Available from British Library Document Supply Centre-DSC:4588.72835(LU-ITS-WP--415) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Validation of FHWA crash models for rural intersections - Lessons learned

A national-level safety analysis tool is needed to complement existing analytical tools for assessment of the safety impacts of roadway design alternatives. FHWA has sponsored the development of the Interactive Highway Safety Design Model (IHSDM), which is roadway design and redesign software that estimates the safety effects of alternative designs. Considering the importance of IHSDM in shaping the future of safety-related transportation investment decisions, FHWA justifiably sponsored research with the sole intent of independently validating some of the statistical models and algorithms in IHSDM. Statistical model validation aims to accomplish many important tasks, including (a) assessment of the logical defensibility of proposed models, (b) assessment of the transferability of models over future time periods and across different geographic locations, and (c) identification of areas in which future model improvements should be made. These three activities are reported for five proposed types of rural intersection crash prediction models. The internal validation of the model revealed that the crash models potentially suffer from omitted variables that affect safety, site selection and countermeasure selection bias, poorly measured and surrogate variables, and misspecification of model functional forms. The external validation indicated the inability of models to perform on par with model estimation performance. Recommendations for improving the state of the practice from this research include the systematic conduct of carefully designed before-and-after studies, improvements in data standardization and collection practices, and the development of analytical methods to combine the results of before-and-after studies with cross-sectional studies in a meaningful and useful way