Private tollroads in urban areas

Governments of all persuasions are increasingly seeking the participation of the private sector in the supply of transport facilities and services. Private sector participation in the financing, construction, operation and maintenance of infrastructure is considered a serious option in a number of countries in the search for ways of providing much needed investment which would otherwise be deferred. This paper considers some economic and financial problems in the private sector provision of major road infrastructure within urban areas. The main issues are attaching prices (i.e. tolls) to the provision of the service, the value of government rights which are being given up either permanently or temporarily, and the identification required by the promoters of the cost of capital which is essential information in establishing the risk. Broader environmental and equity issues are not addressed. If the approach to establishing a private presence in a previously public supply context is handled properly from the outset, the benefits can be significant. Contrarily however, the prospects could be quite undesirable if badly managed, despite the presence of an extended public purse.requests for offprints     

An overview of the abundance and role of protozooplankton in Antarctic waters

The classic view of the Antarctic pelagic system has suggested that food web dynamics are dominated by the diatom-krill food web link. Recent observations, however, have indicated that this is an oversimplification and that the antarctic food web has a complexity similar to that found in lower latitude systems. More specifically, small particulate feeding protozoans appear to have a much greater importance than was previously assumed.Only a few studies have been sufficiently extensive to characterize the Antarctic pelagic protozoan assemblage. These indicate that heterotrophic flagellates (dinoflagellates and other heterotrophic nanoplankton) and ciliates (mostly non-loricate oligotrichs) dominate the protozooplankton assemblages in surface waters. The combined biomass of protozooplankton has been reported to comprise from < 7 to > 75% of the total nano- and microplankton biomass depending on season and location. Protozoans are also found in sea ice communities where their abundances exceed those typically found in the plankton. Several protozoan species occupy both ice and water habitats, suggesting that seasonally melting sea ice may be the source of ice-edge protozooplankton assemblages.The feeding rates of protozooplankton in Antarctic waters are poorly documented. Consumption estimates based on clearance rates and some preliminary grazing experiments, however, indicate that the protozooplankton should be capable of utilizing a significant proportion of the daily primary and bacterioplankton production. Protozoans may contribute to vertical flux, but present evidence suggests that their contribution will be lower than from other sources.     

Modelling the hydrodynamics and ecosystem of the North-West European continental shelf for operational oceanography

This paper outlines an approach to complex spatio-temporal marine ecosystem modelling as applied to the North Western European Continental Shelf. The model presented here combines an eddy-permitting (approximately 6 km horizontal resolution) baroclinic model, the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS), with the European Regional Seas Ecosystem Model (ERSEM). This has been run within an operational framework using operationally available high resolution atmospheric and lateral boundary forcing, allowing hindcast and near-real time nowcast simulations to be performed. The modelled surface temperature and chlorophyll distributions are presented, and interannual variations discussed. Validation of both the physical and ecosystem submodels show the system to be effective, whilst highlighting areas where improvements in the system can be made. Distinct regional differences in predictive skill are shown. The system presented is ready for operational implementation to provide products and services for use both scientifically and in coastal zone and shelf seas management activities. A programme of work to update the system is already in place.     

A derived demand model of regional highway diesel fuel use

A regional, econometric model of heavy truck diesel fuel use is derived based on the theory of production. Input demand functions for new trucks and diesel fuel are specified and estimated. A simple, logistic scrappage model is estimated and used to estimate total heavy truck stocks and diesel-engine heavy truck stocks. Demand equations based on the AIDS almost ideal demand system flexible form cost function are estimated for new heavy truck demand and regional highway diesel fuel demand. New heavy truck demand is found to be elastic with respect to GNP, inelastic with respect to own price, and appears extremely sensitive to short term GNP trends. The short run price elasticity of diesel fuel demand is found to be very small.     

Federal ports policy

In contrast to the centralized port-planning framework that is utilized in some industrialized countries, the US relies on a complex and fragmented framework in which responsibility for the planning, development and operation of landside maritime infrastructure rests with State and local governments. It has been argued that the separation of the federal government from port policy was rooted in the port preference clause of the Constitution. This paper is an effort to determine whether the current decentralized port policy in fact stems from the Constitution and, to that end, reviews how over the years the US Supreme Court has construed the port preference clause in the Constitution. It was found that there is no evidence to support the assertion that the port preference clause has restricted the development of Federal port policy. Moreover, the decentralized and fragmented decision-making process that is evident today does not imply the absence of federal impact. Rather, it reflects federal involvement through multiple agencies and regulatory processes and is a conscious effort, consistent with other areas of transport infrastructure development, to retain local decision-making for infrastructure investments. It is concluded by raising the issue whether current federal involvement in ports (that is, existing federal port policy), through dredging, landside transportation improvements or subsidized capital, among other things, needs to be reappraised before a new round of capital intensive investment begins.     

A dynamic model of travel mode switching behaviour

An analogy is developed between individual traveler mode choice decisions and time-dependent product adoption processes in consumer behaviour. The structure of the adoption sequence is first described conceptually with reference to mode switch ing; this structure is then used to develop a simple mathematical model of mode switching behaviour over time. Factors to be considered in interpreting and operationalizing the model are then discussed at some length. The model appears too complex for direct mathematical solution except in the simplest cases; it may however, be amenable to numerical estimation, given empirical data on mode switching behaviour over time.     

Use of ecological footprinting to explore alternative transport policy scenarios in an Irish city-region

The objective of this paper is to compare the ecological footprint for travel-commuting patterns for the residents of an Irish city-region, that is Limerick city-region, in 1996 and 2002. Scenario building, based on ecological footprint analysis, is used to estimate the impact of different policy choices for 2010. The optimal policy mix for sustainable travel is proposed and consists of a mix of reduced demand through travel demand measures, better spatial planning and technological improvements in fuel economy.     

Parking difficulty and parking information system technologies and costs

Before the implementation of a parking information system, it is necessary to evaluate the parking difficulty, technology choice, and system costs. In this study, the parking problem was quantified by asking parkers to express their parking difficulties in five scaled levels from the least to the most difficult. An ordered Probit model was developed to identify the factors that influence a parker to feel the parking difficulty. The results indicate that the amount of parking information parkers had before their trips was directly related to their parking search time, which in turn, influenced their perceptions of parking difficulty. Parkers' preferences to parking information technologies were identified based on developing binary and multinomial probit models. The results indicate that personal business trips and older persons would like to use the kiosk, while the more educated and males would not. Trips with shopping and social/recreation purposes and the drivers who had visited the destination areas frequently would like to choose roadside display. Drivers who had planned their parking and had Internet access would use in‐vehicle device. The system cost was estimated based on the cost for each component of the system. The results show that providing en‐route parking search information through roadside displays is more expensive than providing pre‐trip information through a web site.