This paper investigates the economic effects of maritime trade through the Port of New York on the New York metropolitan region. It decomposes the impacts associated with the trans-shipment of waterborne exports and imports in 1977 and 1987 into those arising from the changing tonnage of trade and those attributable to the changing commodity mix. Input-output analysis is used to calculate the numbers of jobs, personal and business incomes, and output which arise from each effect. Finally, it examines the impacts on specfic industries and occupations in the region. 相似文献
This paper describes an approach for evaluating alternative traffic detection designs for a signalized intersection. The models described in this paper can be used to determine the average phase duration and frequency of phase “max-out” as a function of the detector loop layout, detector unit timing, traffic demand, and approach speed. Layout and timing are described by the number of detectors on each approach served by the phase, detector location on each approach, detector length, and detector unit and controller time settings. The authors have used the concept of maximum allowable headway (MAH) to combine the many possible combinations of layout and timing variables into one representative quantity, which greatly simplifies the modelling process. The performance models were used to examine the sensitivity of intersection performance to a range of design values. In general, both phase duration and cycle length increase with higher demands or larger MAHs. Multiloop (i.e. two or more detection zones per lane) detector designs typically have larger MAHs than designs with one detector loop per lane. Phase duration and cycle length also increase for very low demand levels. In terms of performance, the maximum green duration was found to have a contrary effect at higher flow conditions. Larger maximum greens were found to reduce delays to the phase in service by reducing the probability of max-out but they increased delays to drivers waiting for service. 相似文献
Abstract Redesign and reuse of waterfronts are a common experience today. Small cities presented with a deteriorating waterfront are faced with formidable economic and institutional impediments to their efforts to reverse the decline. This paper presents some design principles that if followed provide a framework for developing restoration plans. It also describes the efforts of the California State Coastal Conservancy to apply these principles to assist three small cities along California's coast to revitalize their waterfronts. Their experience indicates that in an era of limited budgets waterfront redevelopment can occur with substantial economic benefit where limited funds are applied to often small but crucial elements that result in creating waterside amenities. 相似文献
Current car technologies will not solve upcoming challenges of mitigating greenhouse gas emissions in road transport. Projections of the market penetration by alternative drive train technologies are controversial regarding both forecast market shares and applied scientific methods. Accepting this latter challenge, we provide a (so far missing) overview of methods applied in this field and give some recommendations for further work. Our focus is to classify the applied methods into a convenient pattern and to analyse models from the recent scientific literature which consider the electrification of light-duty vehicles. We differentiate the following bottom-up approaches: Econometric models with disaggregated data (such as discrete choice), and agent-based simulation models. The group of top-down models are subdivided into econometric models with aggregated data (e.g. vehicle stock data), system dynamics, as well as integrated assessment models with general equilibrium models. It becomes obvious that some methods have a stronger methodological background whereas others require comprehensive data sets or can be combined more flexibly with other methods. Even though there is no dominant method, we can identify a trend in the literature towards data-driven hybrid approaches, which considers micro and macro aspects influencing the market penetration of electric vehicles. 相似文献
Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area. 相似文献
The advent of express coach bus lines offering guaranteed seating and emphasizing curbside pickup and drop-off is contributing to a revival in intercity bus travel in the United States. Relatively little is known, however, about the scale and geographic scope of these carriers or the competitive landscape in which they operate. To fill this void, this study evaluates the service networks operated by the two largest express coach operators in the country, BoltBus and Megabus, and evaluates a data set of 4775 fares sold on megabus.com. The results show that these carriers cumulatively serve 127 intercity segments and operate about 52.9 million bus miles per year. Together, these carriers have grown to about one third of the size of Amtrak, with Megabus and BoltBus providing 3.3 billion and .69 billion seat miles of service, respectively, compared to Amtrak’s 12.8 billion. With respect to the types of routes it serves and the competition it faces, Megabus has evolved into a carrier quite different than Boltbus; more than one third of Megabus’ bus miles are operated on segments without Amtrak service, while virtually all of BoltBus’ miles face this competition. The analysis of Megabus’ pricing shows that fares rise modestly within 2 weeks of departure, while the per-mile costs are much less ($.08/mile) for 300–399 mile trips than for those 50–99 miles ($.22/mile). Nevertheless, the dispersion of fares tends to fall as the departure date nears, regardless of distance. Together, these prominent bus lines serve 66 of the 100 most heavily traveled U.S. city pairs that have characteristics suitable for intercity bus service—which is more than Amtrak. With further growth on the horizon, planners, federal regulators, and researchers should collaborate on establishing reporting requirements for this expanding sector.
Transportation - Practitioners often use demand models to predict how neighborhood-level land use, infrastructure, demographic, and other changes may impact transportation systems. Few of the... 相似文献