Abstract

In this paper we describe how we included travel time variability in the national Dutch transport forecasting model and what the policy impacts of this new forecasting tool are. Until now, travel time reliability improvements for road projects were included in Dutch cost-benefit analysis (CBA) by multiplying the travel time benefits from reduced congestion by a factor 1.25. This proportionality is based on the linkage between congestion reduction and reliability improvements. However, this treatment of reliability is not useful to evaluate policies that especially affect travel time variability. From the start, this method was provisional and meant to be replaced by a better method capturing travel time variability. For this, we derived an empirical relation between the standard deviation of travel time, mean delay of travel time and length of route. This has been implemented in the national Dutch model as a post processing module. The new travel time reliability forecasting model will be incorporated in the Dutch guidelines for CBA. Document type: Part of book or chapter of book

Abstract

A brief review of long run projections of demand for road transport suggests that problems related to road network congestion and greenhouse gas emissions are likely to become more pressing than they are now. Hence we review, from a macroscopic perspective, popular policy measures to address these problems: stimulating modal shift, regulating land use to reduce car use, and boosting low carbon technology adoption to reduce greenhouse gas emissions. We find that these policies can produce tangible results, but that they may have unintended consequences that drive up costs considerably.

Abstract

This paper studies some of the properties and fundamentals of static models of road traffic congestion that have triggered much debate in the literature. The first part of the paper focuses in particular on the difficulties arising with the backward-bending cost curve in the context of 'continuous congestion'. Therelevance of the backward-bending segment of the cost curve for the static analysis of congestion is questioned by demonstrating that 'equilibria' on this segment produce upwards shifts of the cost curve itself, and can therefore not be of a stationary nature. Next, the implications for static models of 'peakcongestion' are considered. In doing so, the paper addresses the implicit assumptions, particularly on the nature of scheduling costs, that are necessary to render static models of peak congestion internally consistent. The paper ends with a brief discussion of the implications for dynamic models of peakcongestion.