The missing link: bicycle infrastructure networks and ridership in 74 US cities

Cities promote strong bicycle networks to support and encourage bicycle commuting. However, the application of network science to bicycle facilities is not very well studied. Previous work has found relationships between the amount of bicycle infrastructure in a city and aggregate bicycle ridership, and between microscopic network structure and individual tripmaking patterns. This study fills the missing link between these two bodies of literature by developing a standard methodology for measuring bicycle facility network quality at the macroscopic level and testing its association with bicycle commuting. Bicycle infrastructure maps were collected for 74 Unites States cities and systematically analyzed to evaluate their network structure. Linear regression models revealed that connectivity and directness are important factors in predicting bicycle commuting after controlling for demographic variables and the size of the city. These findings provide a framework for transportation planners and policymakers to evaluate their local bicycle facility networks and set regional priorities that support nonmotorized travel behavior, and for continued research on the structure and quality of bicycle infrastructure and behavior.     

Rules for aggregated satisfaction with work commutes

In general trips frequently entail several stages varying in mode, duration, and other factors. In some way travelers aggregate their satisfaction with the stages to satisfaction with the whole trip. In this paper we address the question of how this aggregation is made. We use data from a Swedish survey measuring satisfaction with commutes to and from work and with the stages of the commutes. We test several aggregation rules for their goodness of fit to the observations. Our results show that a normatively correct averaging rule that takes into account the relative durations of the stages out-perform heuristic aggregation rules such as the peak-end, summation, and equal-weight averaging rules. We note that this does not exclude that the heuristic aggregation rules apply to other trips than repetitive commute trips.     

Green shipping practices and firm performance

Global economic development is facilitated by the commercial shipping industry. Shipping operations contribute to the growth of international trade activities, which heavily count on ships to carry cargoes from places of production to places of consumption. Despite its importance, there have been growing concerns about the environmental impacts caused by shipping activities in international trade. To balance environmental protection and productivity, many shipping firms have begun to adopt green shipping practices (GSPs) to improve their operations in a more environmentally friendly manner. GSP consists of six dimensions, namely, company policy and procedure (CPP), shipping documentation (SD), shipping equipment (SE), shipper cooperation (SC), shipping materials (SM), and shipping design and compliance (SDC). GSP is becoming an important aspect of shipping operations. It is timely for the shipping industry to evaluate firm capability in carrying out greening operations, that is, firms’ “greening” capability. Firm capability comprises two key elements: one is embedded in firms’ business routines or activities, and the other concerns firms’ ability in transforming inputs into outputs. GSPs can be considered as inputs while firm performance measures as outputs. This study uses an input/output approach to examine the greening capability (GC) of shipping firms. The results indicate that shipping firms are relatively weak in the practices of SC and SE, while the capability scores of SM, CPP, SDC, and SD are all close to 1, with an average score of 0.927, 0.920, 0.924, and 0.978, respectively. Academic and managerial significance of the findings are highlighted.     

浅谈抱箍法在高林台河2号大桥盖梁施工中的应用

桥梁无支架施工在当前高速公路工程建设中越来越显示出其优越性,特别是在地势起伏较大、盖梁下面地质情况较差的情况下更是适宜的施工方法。抱箍法是无支架施工的一种新方法,其特点是投入小,施工方便,目前已成为桥梁盖梁施工的首选方案,应用也越来越广泛。     

Upstream pollution sources and coastal water quality protection in North Carolina

Abstract

A watershed‐based approach to water quality management is necessary for protecting coastal water quality, but the relative importance of inland pollution sources on estuaries is often overestimated. This can lead to a misallocation of coastal water protection resources and ignorance of coastal zone pollution sources. This overestimation of upstream contributions is attributable to a failure to recognize that many estuaries have little or no inland drainage area, the confusion of basinwide pollutant loading with pollutant delivery to estuaries, the low delivery ratios for many pollutants within drainage basins, and disproportionately high pollutant delivery for sources within the coastal zone. Examples are given from North Carolina. As a general rule, resources expended on pollution control within or near the coastal zone will result in more coastal water quality improvement per unit effort than resources expended upstream.     

Planning and control of paratransit services in Hong Kong

As paratransit services, Hong Kong's taxis and public light buses (PLB) carried some 30% of the 9.7 million daily public transport boardings in Hong Kong in 1988. Most of the vehicles are individually owned, and services are operated as commercially viable concerns. While operators have a high degree of operational flexibility, taxis and PLBs are closely regulated by the Government. The fleet sizes are controlled by licensing. There is a system of zoning for taxis, and operational prohibitions and restrictions for PLBs. Over the years, Hong Kong has developed some practicable means of operational control on taxis and PLBs. It has been 20 years since PLBs were legalized in 1969. The transition experienced by this mode, from no control to regulated operations, signifies a major step forward from the point of view of transport administration. The Government's participation in the planning for PLB services has guided the development of this mode. In this paper, the planning and control mechanisms for Hong Kong's paratransit modes are introduced. Identified deficiencies are also discussed.     

Research review of air traffic management

As air transport demand keeps growing more quickly than system capacity, efficient and effective management of system capacity becomes essential to the operation of the future global air traffic system. Although research in the past two decades has made significant progress in relevant research fields, e.g. air traffic flow management and airport capacity modelling, research loopholes in air traffic management still exist and links between different research areas are required to enhance the system performance of air traffic management. Hence, the objective of this paper is to review systematically current research in the literature about the issue of air traffic management to prioritize productive research areas. Papers about air traffic management are discussed and categorized into two levels: system and airport. The system level of air transport research includes two main topics: air traffic flow management and airspace research. On the airport level, research topics are: airport capacity, airport facility utilization, aircraft operations in the airport terminal manoeuvring area as well as aircraft ground operations research. Potential research interests to focus on in the future are the integration between airspace capacity and airport capacity, the establishment of airport information systems to use airport capacity better, and the improvement in flight schedule planning to improve the reliability of schedule implementation.     

Deregulating the bus industry in Britain: a reply

In the last four years, some 20 urban areas in the UK have commissioned or considered conducting Integrated Transport Studies, which are designed to develop a transport strategy for the next 20–30 years. Such studies represent a new approach to transport policy formulation, since they respond to a vision of the future for the area, treat a wide range of transport and land use policy instruments, emphasize synergy between those instruments, and provide a framework for facilitating action rather than a rigid blueprint for the future. They also differ from past studies in the speed with which they have been conducted, and in the analytical techniques which have made this possible. This paper reviews the background to these studies, the evaluation approach adopted, the policy instruments considered and the analytical methods developed for the studies. It concludes with an assessment of the policy implications stressing in particular the need to reduce trip length, the crucial impact of pricing as an instrument of transport policy, the importance of achieving synergy in strategy development, and the requirement for a common basis for evaluating and financing different transport policy instruments.     

Nigerian railways: problems and prospects

The very special topography of Greece with the hundreds of mainland and island ports generates vast possibilities for developing routing networks to link the ports to each other while satisfying total demand. An algorithm which minimizes total operating costs (fixed and variable) has been adapted and used to determine an optimal network solution. The total operating costs of this solution is compared to the total operating costs of the existing (1964 data) network and the optimal networks when fixed and variable costs are minimized independently. It is found that the actual network follows the minimal total operating costs solution quite closely.     

Book reviews

TRANSPORT AND REURBANISATION, by Leo H. Klaassen, Jan A. Bourdrez and Jacques Volmuller. Gower Press, England, 1981. 214 pp.

TRANSPORT AND PUBLIC POLICY PLANNING, edited by David Banister and Peter Hall. Mansell Publishing Ltd., London, 1981. 455 pp.

ACCESS FOR ALL by K. H. Schaeffer and Elliott Sclar. Columbia University Press, 1982. 182 pp.

ENVIRONMENTAL ANALYSIS OF TRANSPORTATION SYSTEMS, by Louis F. Cohn and Gary R. McVoy. John Wiley, 1982. 374 pp. (£35.00).

THE ECONOMICS OF URBAN FREIGHT TRANSPORT, by K. J. Button and A. D. Pearman. The MacMillan Press Ltd., London. 218 pp. (£20.00).

TRANSPORTATION MARKINGS, BY Brian Clearman. University Press of America, 1981. 459 pp.

REGULATION AND POLICIES OF AMERICAN SHIPPING, by Ernst G. Frankel, Auburn House Publishing Co., Boston, Massachusetts. 321 pp. ($24.95)