Control of drivers' route choice: Pipe dream or panacea?

In most large cities traffic flow is controlled or manipulated in a number of ways. The methods used are mostly negative in the sense that they restrict the driver's choice of alternative routes rather than encourage him to use a particular one. This paper reviews some of the conventional measures and goes on to consider whether a more positive approach to route control might be justified, by inducing a more efficient or acceptable pattern of traffic movement in urban areas. The principal criteria for an efficient pattern are taken to be the total rate of expenditure of vehicle mileage and the frequency of route crossings, and an attempt is made to evaluate the potential benefits of route control in these terms. Social, technical and political considerations suggest that compulsory control will not be feasible for some time (at least, in the UK), but if the benefits to drivers as individuals can be shown to be worthwhile an advisory system might be practicable. Some possible systems are briefly outlined.The author is grateful to the City Engineer of Westminster City Council, Mr A.J. Cryer, for permission to publish this paper,which, however, does not necessarily represent the views . City Council. The author is greatly indebted to E. M. Holroyd for numerous suggestions and advice.     

Wave data assimilation with the Kalman filter

A new data assimilation method for ocean waves is presented, based on an efficient low-rank approximation to the Kalman filter. Both the extended Kalman filter and a truncated second-order filter are implemented. In order to explicitly estimate past wind corrections based on current wave measurements, the filter is extended to a fixed-lag Kalman smoother for the wind fields. The filter is tested in a number of synthetic experiments with simple geometries. Propagation experiments with errors in the boundary condition showed that the KF was able to accurately propagate forecast errors, resulting in spatially varying error correlations, which would be impossible to model with time-independent assimilation methods like OI. An explicit comparison with an OI assimilation scheme showed that the KF also is superior in estimating the sea state at some distance from the observations. In experiments with errors in the driving wind, the modeled error estimates were also in agreement with the actual forecast errors. The bias in the state estimate, which is introduced through the nonlinear dependence of the waves on the driving wind field, was largely removed by the second-order filter, even without actually assimilating data. Assimilation of wave observations resulted in an improved wave analysis and in correction of past wind fields. The accuracy of this wind correction depends strongly on the actual place and time of wave generation, which is correctly modeled by the error estimate supplied by the Kalman filter. In summary, the KF approach is shown to be a reliable assimilation scheme in these simple experiments, and has the advantage over other assimilation methods that it supplies explicit dynamical error estimates.     

The Rolling Motions of Road Vehicles

This paper examines the rolling motions of vehicles with pneumatic tires. From a simplified analysis two sources of instability are identified-one related to center of gravity position and the other to tire and suspension characteristics. When a specimen vehicle is considered, it is shown that current semi-trailer design can display instability from either source.     

Coastal Management Using Public Judgments,Importance Scales,and Predetermined Schedule

A predetermined schedule of sanctions and regulations that reflect both scientific knowledge of resources and the preference and judgments of resource users in the community may provide a useful guide for management decisions involving complex coastal resource systems. Such a schedule can be implemented by constructing scales reflecting public judgments of the relative importance of adverse impacts on resources, or of activities causing such impacts. The importance scales can then be used to assess existing regulations and current management priorities and to serve as a guide for revisions and changes to current practice, for the design of new policy, for rationalizing regulatory controls, and for determining damage awards and other deterrence sanctions. The resulting evolution of a schedule can improve the consistency of resource use with community preferences by, for example, prescribing more severe restrictions on what are widely agreed to be more serious harms and lesser controls on less important ones. The application of this approach is demonstrated using Ban Don Bay, Thailand.     

Ship assignment with hub and spoke constraints

As the shipping industry enters the future, an increasing number of technological developments are being introduced into this market. This has led to a significant change in business operations, such as the innovative design of hub and spoke systems, resulting in cargo consolidation and a better use of the ship's capacity. In the light of this new scenario, the authors present a successful application of integer linear programming to support the decision-making process of assigning ships to previously defined voyages — the rosters. The tool used to build the final models was the MS-Excel Solver (Microsoft® Excel 97 SR-2, 1997), a package that enabled the real case studies addressed to be solved. The results of the experiment prompted the authors to favour the assignment of very small fleets, as opposed to the existing high number of ships employed in such real trades,     

Coastal Crisis: The Failure of Coastal Management in the Spanish Mediterranean Region

It is a fact that coastal zones in the Mediterranean are becoming progressively more seriously degraded. Instrumental to the phenomenon in Spain is the evident failure of the coastal management that the institutions have pursued for over three decades, both under the old, state-centralized model, and the new organizational model with the political division of land into autonomous regions. This failure can in part be explained not only by the inadequate tools the administration possesses to address the dynamism and complexity of the new economic activities that have sprung up along the coast, but also by incoherent sectoral policies. Finally, there has been no all-encompassing political strategy capable of dealing with coastal communities' demands for development and the need for the protection of ecosystems and their natural resources. All this has resulted not only in a deterioration of the area, but also in the discrediting of actions implemented by the institutions, and their plans and programs being perceived as an obstacle to economic development.     

The Potential Economic Benefits of Coastal Ocean Observing Systems: The Southeast Atlantic Region

The Southeast Atlantic Coastal Ocean Observing System (SEACOOS) collects, manages and disseminates coastal oceanic and atmospheric observation information along the Atlantic coast of the southeastern United States. This article estimates the benefits of SEACOOS information in eleven benefit categories. Following a methodology used in similar studies of other U.S. coastal regions, we evaluate the impacts of conservative changes in economic activity in each benefit category. The annual economic benefit of SEACOOS information is $170 million (2003 $), an estimate that falls between annual benefits of $33 million for the Gulf of Maine region and $381 million for the Gulf of Mexico.     

Understanding successful workplace travel initiatives in the UK

Across the world, there is increasing interest in managing car traffic. One approach developed for addressing the journey to work is known as ‘workplace travel planning’. This paper primarily reports on 20 case studies of UK employers undertaking travel planning, who had cut commuter driving by an average of 18%. It concludes that considerable behavioural change can be achieved in a variety of contexts – but employers usually need an overall strategy that addresses car parking, in addition to improving alternative travel modes. Moreover, a more comprehensive national strategy is needed, if travel planning is to achieve its potential.     

Port administration and coastal zone management in Vancouver,British Columbia: A comparison with Seattle,Washington

Large North American ports are encountering serious management challenges. Surrounding communities, environmental interest groups, and government policy are focusing on protection and enhancement of public coastal amenities. In Vancouver, the federal port management system historically enabled national trade interests to override local and regional objectives at the discretion of port decison makers. In contrast, the Port of Seattle is administered at the local level, and legislation and policy require that local publics are involved in decision‐making. Recently, VPC established itself as the vanguard among Canada's major ports in the advancement of progressive management. Nevertheless, the adoption of new policies would ensure that Vancouver, and Canada's other ports, continue to be responsible leaders in Canadian coastal management. These policies include: federal, municipal, and provincial government representation on the local board of directors; strengthening community involvement; creation of a standing planning advisory committee; subjecting Canadian ports to the federal environmental assessment law; and adoption of explicit land and water use regulations.     

Affordable housing in California's Coastal Zone: A tale of state authority vs. local autonomy

Abstract

This article examines the efforts of the California Coastal Commission to pursue simultaneously goals of environmental quality and affordable housing in the same state‐imposed regulatory program. The authors conclude that the Commission made substantial progress toward realizing both ends. However, the coastal body fell victim to its own successes, and housing was removed from its jurisdiction. As the Coastal Commission exercised its authority, opposition grew in strength and numbers. Key opponents included local government, which lost land‐use regulatory power to the Commission, the building industry, whose relationships with coastal localities were disrupted, and local property owners, whose land was restricted to uses other than the most profitable one.