Time, speeds, flows and densities in static models of road traffic congestion and congestion pricing

This paper deals with some of the features of static models of road traffic congestion that have caused much debate in the literature. It first focuses on the difficulties arising with the backward-bending cost curve defined over traffic flows in the context of `continuous congestion'. The relevance of the backward-bending segment of this curve is questioned by demonstrating that the `equilibria' on this segment of the cost curve are dynamically infeasible. Next, the implications for static models of `peak congestion' are considered. In doing so, attention is paid also to 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 peak congestion.

Urban sustainability, agglomeration forces and the technological deus ex machina

This paper addresses the issue of spatial environmental externalities from a spatial general equilibrium perspective. We present a general equilibrium model of an island economy, with one city and a rural hinterland. Apart from market-internal interactions such as those governing trade and locational choice, the small economy considered encompasses a number of spatial external effects. Agglomeration externalities explain why industrial production is concentrated in a city, where land prices are higher than elsewhere. Industrial production however leads to environmental pollution, which negatively affects the quality of life within the city and rural agricultural production elsewhere. The paper explores the welfare properties of market-based spatial general equilibria compared to efficient configurations. The conclusions allow a welfare economic assessment of the currently popular concept of ‘ecological footprints’ from a spatial general equilibrium viewpoint.

Energy policies in spatial systems: A spatial price equilibrium approach with heterogeneous regions and endogenous technologies

This paper presents a framework for analysing spatial aspects of environmental policies in the regulation of trans-boundary externalities. A spatial price equilibrium model for two regions is constructed, where interactions between these regions can occur via trade and transport, via mutual environmental spill-overs due to the externality that arises from production, and via tax competition when the regions do not behave cooperatively. Explicit attention is also given to the additional complications arising from emissions caused by the endogenous transport flows.

Inside the queue: hypercongestion and road pricing in a continuous time - continuous place model of traffic congestion

This paper develops a continuous time - continuous place model of road traffic congestion, based on car-following theory. The model fully integrates two archetype representations of traffic congestion technology, namely "flow congestion", originating in the works of Pigou, and "vertical queuing" models, pioneered by Vickrey. Because a closed-form analytical solution of the formal model does not exist, its behaviour is explored in a numerical exercise. In a setting with endogenous departure time choice and with a bottleneck halfway the route, it is shown that "hypercongestion" can arise as a dynamic - transitional and local - equilibrium phenomenon. Also dynamic toll schedules are explored. It is found that a toll rule based on an intuitive dynamic and space-varying generalization of the standard Pigouvian tax rule can hardly be improved upon. A naïve application of a toll schedule based on Vickrey´s bottleneck model, in contrast, performs much worse and actually even reduces welfare.

Pricing, Capacity Choice and Financing in Transportation Networks

This paper explores the inerrelations between pricing, capacity choice and financing in transportation networks. It builds on the famous Mohring-Harwitz result on self-financing of optimally designed roads under optimal congestion pricing, and specifically asks the following questions: (1) to what extent does the result apply under conditions of second-best pricing?; (2) which are the implications of having uncongested (e.g. rural) roads in a network?; and (3) what is the role of fixed (annual) taxes in this context? The paper develops a small network model, with endogenous car-ownership, in order to study these questions both from an analytical and a numerical viewpoint.

Editorial: parking in the connected and automated era: operation, planning, and management

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