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91.
92.
William Ritchie 《WMU Journal of Maritime Affairs》2004,3(2):193-204
The impact on the marine environment of the operation of the Sullom Voe Oil Terminal and its major port facility in the Shetland
Islands has been monitored continuously for more than twenty-five years. The site of this very large terminal straddles a
peninsula and the separation of the impact of the port on the sheltered west side (Sullom Voe) and the aqueous discharge from
the terminal to the east, into the strong tidal current of Yell Sound, has proven to be advantageous. There are two types
of monitoring, statutory (to comply with relevant legislation) and voluntary (to establish good practice and to examine a
wider range of impacts e.g. island-wide ornithology). The latter function is undertaken by an independent advisory committee
(SOTEAG). Over time, the nature and amount of voluntary monitoring has decreased in response to the long term evidence that
both terminal and port operations are having little or no impact on a wide range of habitats and species. Voluntary monitoring
also acts as an independent check on both compliance and other forms of environmental assessment. Although the terminal is
now operating at less than half its peak capacity, this does not mean that there has been apro-rata decrease in monitoring
activity. 相似文献
93.
This paper addresses a general stochastic user equilibrium (SUE) traffic assignment problem with link capacity constraints. It first proposes a novel linearly constrained minimization model in terms of path flows and then shows that any of its local minimums satisfies the generalized SUE conditions. As the objective function of the proposed model involves path‐specific delay functions without explicit mathematical expressions, its Lagrangian dual formulation is analyzed. On the basis of the Lagrangian dual model, a convergent Lagrangian dual method with a predetermined step size sequence is developed. This solution method merely invokes a subroutine at each iteration to perform a conventional SUE traffic assignment excluding link capacity constraints. Finally, two numerical examples are used to illustrate the proposed model and solution method. 相似文献
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96.
In conventional transportation planning models, it was always assumed that the population density is given and fixed in the study areas. Therefore, the effects of population density on travel choice have not been explicitly incorporated into these existing models for long-term transportation planning. Meanwhile, travel choice models in previous studies are usually developed by using discrete choice theories or user equilibrium principle. Thus, many significant characteristics of travelers’ behaviors, such as risk preference and learning process over time, cannot be considered in these conventional models. This article proposes a convex prospect theory-based model to investigate the effects of population density on the travelers’ mode-choice behavior under an advanced transportation information system (ATIS) in a multimodal transportation corridor. It is shown that population density is closely co-related to the modal split results and dependent on the performance of the railway mode in the study corridor. The park-and-ride mode may not be suitable for areas with high population density. This article also investigates the travelers’ reference points on the generalized travel costs by modes. A numerical example is given to illustrate the properties of the proposed model together with some insightful findings. 相似文献
97.
The precise estimation of the annual average daily traffic (AADT) is a task of significant interest for many transportation authorities and Departments of Transportation. In this study, three methods are developed to improve the assignment of short‐term counts to seasonal adjustment factor (SAF) groupings: the traditional functional classification, a discriminant analysis (DA), and a new statistical approach based on a weighted coefficient of variation (WCV). The data analyzed within this study are generated from all available continuous counters within the State of Ohio between 2002 and 2006. The analysis is conducted using SAFs that are separately calculated for the total volume and the directional specific volumes of a site. The results show that the directionally based assignment errors are statistically lower at a 95% confidence interval when compared with those generated by the total volume analysis. It is also found that the hourly time‐of‐day factors are more important in the assignment process than the average daily traffic. The directionally based WCV produces a decline in the average mean absolute percentage error (MAPE) over the roadway functional classification by 58% and in the standard deviation of the absolute error (SDAE) by 70%. On the contrary, the directionally based DA lowers the MAPE and the SDAE by 35% and 60%, respectively. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
98.
ABSTRACT As maintenance and operation costs increase with usage over time, equipment is replaced when the value of new equipment is more attractive. Some methods have been developed to solve this problem. In the public transport sector, such problems are frequently analyzed by fleet managers and determined by bus age restriction regulations. We propose an Integer Programming model that integrates both budgetary and environmental constraints (CO2 emissions) which, as far as we know, have not previously been studied in conjunction. The study aims to determine the optimal replacement plan for a fleet of diesel buses of different size, age, maintenance costs and emissions rates, with new (less polluting) diesel buses over a time horizon of 50 years. The results indicate that it is possible to reduce emissions with a low annual budget using an optimal replacement policy. 相似文献
99.
ABSTRACTThe advent of road transport automation is suggested to be one of four key technological transitions that could amount to a major transformation in mobility practices. Specifically, fully Automated Vehicles (AVs) might replace the current private car owner user model with fleets of on-demand synchronously-shared automated taxis. However, significant barriers to this vision becoming the norm remain. This paper examines two critical user-acceptance aspects of the transition: willingness to adopt AVs, and willingness to share an AV with others, particularly strangers. Our novel survey (n?=?899) included a choice experiment featuring four future full automation transport services (private, synchronously/asynchronously shared, and public). Cluster analysis examined respondents' preferences and their demographic and psycho-social characteristics. We uncover significant uncertainty about willingness to adopt automation and sharing, and important differences between clusters within our sample. For example, under 50% of participants report willingness to use an AV over their normal mode, or would prefer an automated option to a current human-driven option. Our findings raise critical questions for policymakers and transport authorities. Not least, how can AV technologies help realise the environmental and social benefits of widespread vehicle sharing in a context of a travelling public that still prefers its privacy on-the-move? 相似文献
100.
Abstract The recently adopted Law of the Sea (LOS) Convention contains a provision allowing coastal nations to adopt 12‐mile territorial seas. Already 104 nations (of a total of 137 coastal nations) have claimed territorial seas of 12 miles or wider. The paper discusses the factors which, in the opinion of the authors, could cause the United States to broaden its territorial sea from the present 3 miles to 12 miles within the next half‐dozen years or so. The state‐federal ocean use and resource management issues that will be raised by such a move are reviewed and options for dealing with the jurisdictional issues are developed. Given the political and economic volatility of these issues and their complexity, the use of a broadly representative and well‐staffed study commission to formulate a course of action is suggested. 相似文献