Sustainability and automobility among the elderly: An international assessment

In the next three decades there will a huge increase in both the absolute number of older people and in their percentage of the populationin almost all Western European countries, North America, and Australia. Most older people will have active lifestyles in which mobility and access play a major role and almost all older men and a majority of older women will be car drivers, used to the convenience and flexibility which the car provides.Using data from the US, Australia, Germany, New Zealand, Norway, and the United Kingdom, the paper shows that, in spite of cultural and policy differences, older people around the world are more likely to have a license, to take more trips, and to do so more often as the driver of a car than older people just a decade ago; they are also less likely to use public transit. These trends have a number of sustainability implications – the most obvious one is increased environmental pollution. For example, even though older people may travel less than younger drivers they may be polluting proportionately more because a) they are less likely to make as great a proportion of trips in public transit as younger people and b) the trips they do make may create more pollutants. In addition, older drivers may incur more wasted miles due to wayfinding errors and trip-scouting behavior. And when older people curtail their driving, younger family members may have to increase (or lengthen) their trip-making to provide needed services or additional transportation.While this paper stresses the environmental problems posed by an aging population, effective strategies arise from a focus on a broader definition of sustainability. The most important approach is to accept the inevitable and work to make the private car "greener" and safer. New transit service concepts and strategic community and neighborhood design and service elements can complement the development of cleaner cars.Although many of the potential strategies are not new, or can be expensive to implement, the convergence of environmental concerns with other problems arising from the automobility of the elderly – including increasing crash rates and serious loss of mobility among those unable to drive – may make these policies more politically viable than in the past.     

Economic value of natural Coastal wetlands: A critique

Recent estimates by J. Gosselink, E. Odum, and R. Pope of the economic value of natural wetlands have had considerable impact on analyses and discussions of public policies concerning natural wetlands management. However, these economic value estimates are neither conceptually nor empirically correct. First, these workers failed to recognize the nature of the process by which economic values are determined and made an illegitimate marriage of the principles of systems ecology and economic theory. Second, where Gosselink et al. attempted to apply proper economic principles, their calculations resulted in economic value estimates that are most likely in error.     

Nutrient dynamics and phytoplankton development along an estuary–coastal zone continuum: A model study

This study presents a first attempt to quantify the biogeochemical transformations and fluxes of carbon and nutrients along the entire mixing zone of the shallow, tidally-dominated estuary–coastal zone continuum of the Scheldt (Belgium/The Netherlands). A fully transient, two-dimensional, nested-grid hydrodynamic model of the continuum is coupled to the biogeochemical MIRO model for the coastal zone and the CONTRASTE model for the estuary. Transient model simulations are performed with a high spatial (80–750 m) and temporal (30 min) resolution over a period of one year (January–December 1995). The high temporal resolution allows including the short-term variability triggered by the tides, the freshwater discharge and the wind stress. System scale simulations provide time series of nutrient transformations and fluxes along the entire estuary–coastal zone continuum, as well as highly resolved nutrient inventories for the estuarine and the coastal zone sub-domains. Simulation results reveal that the balance between highly variable estuarine nutrient inputs and physical constrains set by the unsteady residual transport field exert an important control on the magnitude and succession of phytoplankton blooms and the ecosystem structure in the coastal zone. In addition, they suggest that the poorly surveyed estuarine–coastal zone interface plays a central role in the continuum. In this dynamic area, marked spatial concentration gradients develop and episodically lead to a reversal of material fluxes from the coast into the estuary. During distinct episodes of the productive period, euryhaline coastal diatoms intrude far upstream into the saline estuary. This intrusion reduces the estuarine nutrient concentrations and export fluxes, thereby reinforcing the nutrient limitation in the coastal area. As a consequence, the estuarine filter does not operate independently from the processes in the coastal zone. The dynamic interplay between the two ecosystems and the intense process rates operating at their transition, therefore, strongly supports our continuum approach.     

Peak-period traffic congestion: A state-of-the-art analysis and evaluation of effective solutions

This paper reports on an analysis of a range of largely non-construction congestion reduction techniques which was funded by the U.S. National Cooperative Highway Research Program (NCHRP). A number of evaluations of the direct and indirect effec tiveness, costs, timing and feasibility of 22 major classes of promising techniques was performed. Based on this analysis, the study team evaluated 17 of these techniques as both effective and feasible in a U. S. institutional context.However, none of these 17 offered more than marginal reductions in peak-period traffic congestion when applied individually. Some techniques affected so small a percentage of travelers that reductions in congestion would not be discernible. Other techniques promised significant congestion reductions in theory but did not realize that promise in practice. It was concluded that many techniques could be implemented together with the potential for far greater combined effectiveness.An analysis was performed to determine how best to package or jointly implement promising techniques to optimize their combined effectiveness. It was found that all promising techniques could not be applied together because of conflicts in their impact. This analysis suggested eight sample packages or combinations of mutually supportive techniques. These eight packages were subjected to evaluations similar to those performed for individual techniques; while the packages are merely examples of potential combinations, the evaluation methodology employed should be of continuing use to local transportation planners.This paper was developed from NCHRP Report 169, Peak-Period Traffic Congestion, Options for Current Programs, and Peak-Period Traffic Congestion: State-of-the-Art and Recommended Research (NCHRP Agency Draft) By Robert Remak and Sandra Rosenbloom.This study was conducted under National Cooperative Highway Research Program Project 7/10. The opinions and findings expressed or implied in this paper are those of the author. They are not necessarily those of the Transportation Research Board, The National Academy of Sciences, the Federal Highway Administration, the American Association of State Highway and Transportation Officials, nor of the individual states participating in the National Cooperative Highway Research Program.On Leave to the U. S. Department of Transportation, Washington     

The nexus between port governance and performance

The diversity of port governance models in the world, sometimes even within the same country, has aroused the interest of researchers. This study is based on contingency theory to support the port governance model. The purpose is to understand the port governance model and the relation with port performance. There are three objectives: to analyze the port governance mechanisms; to analyze the port performance factors; and to understand the influence of the governance model mechanisms on port performance. A factorial analysis was used to determine the main components, and the methodology of the structural equation model was used to analyze a survey sample of 105 valid responses from specialists and managers of port user’s companies that operate in the main Portuguese ports. This study demonstrates that port governance model influences directly the port performance. The main contribution of this paper to the literature is providing a set of factors that public managers may decide when changing the characteristics of the port governance models to ensure their performance. It was also observed the approximation of the port expert vision of port governance with models described in literature.     

Transition between Signal Timing Plans: A Methodological and Analytical Overview

Abstract

The transition phase is generally defined as the process of switching from one timing plan to another; this process may include changes in offset, phase split or cycle length until coordination for a new timing plan is reached once again. As noted in the literature, transition phases between timing plans may lead to severe disruptions of traffic flow, resulting in potentially lasting effects. The aim of this paper is to comprehensively review, classify and analyse the literature regarding transition between different timing plans to highlight existing research gaps and give researchers a starting point to continue contributing with solutions to the transition problem. Regarding transition approaches, a gap concerning mathematical approaches was deemed significant as a transition could be greatly benefited by simultaneously optimising more than one operational measure of effectiveness through multi-objective mathematical models. Moreover, in the analysis of applied approaches, Shortway algorithms generally outperformed other practical methods under different scenarios.     

Adolescents and their aspirations for private car-based transport

Transportation - The need to transition away from the current car-dominated transport system is well documented in sustainability, health and transportation literatures. Despite growing interest in...     

The concept of “shipowner” under new maritime labor law (MLC, 2006): does the shipowner own the ship? (comparative analysis of national law of Denmark,Finland, Germany,Norway, and the United Kingdom)

The identification of the responsible shipowner is essential for seafarers in order to claim payments and compensation in respect of their employment on board a ship. Often this may be difficult because of corporate arrangements and the many intermediaries traditionally involved in ship operation. The Maritime Labour Convention 2006 (MLC, 2006), adopted by the International Labour Conference (ILC) 94th (Maritime) Session in 2006, entered into force on August 2013; it significantly affects the shipowner’s responsibility in respect to seafarers’ employment. Taking into account the mentioned issue, the article examines the concept of “shipowner” under the MLC, 2006 and presents comparative analysis of the relevant national law implementing the MLC, 2006 in Denmark, Finland, Germany, Norway, and the United Kingdom.