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21.
In Britain, capacity charges are levied on train operators to cover the costs imposed by increased reactionary delays – i.e. the delay that an already late train causes to a following train. These charges are based on the link between capacity utilisation and the level of reactionary delay. An established method for measuring capacity utilisation was adopted called The Capacity Utilisation Index (CUI). In this paper, we propose an alternative methodology based on the theory that the level of reactionary delay will be determined by the minimum gaps that exist between trains. We test this measure with a new data-set for the East Coast Main Line and show that it performs better than CUI. Finally, we comment on the implications of this finding for charging and for the construction of timetables. 相似文献
22.
Reducing traffic volumes and CO2-emissions from freight transport has proven difficult in many countries. Although the increasing suburbanization of warehouses is seen as a relevant land use trend, comprehensive analyses of their impact remain scarce. This study uses real data in modeling transport, costs, environmental and modal effects from warehouse relocations around Oslo and Trondheim (Norway). Results indicate that for Oslo, traffic performance (ton-km), CO2-emissions, and transport costs increase following warehouse suburbanization. For Trondheim, transport performance and CO2-emissions increase less, while transport costs decrease marginally. We conclude that specific case characteristics (geography and trade patterns) are important in determining the strength and direction of effects, and expect that common concomitant developments (warehouse centralization and consolidation) would lead to more pronounced results. Our findings confirm some, but challenge other, findings from the relatively scarcely literature available. Finally, the study's more general insights and observations can help advance similar analyses beyond Norway. 相似文献
23.
Daniel Baldwin Hess 《Transportation》2012,39(2):247-266
The walking trip from an origin or destination to a bus stop or transit station can be a barrier to riding transit for older
adults (over age 60) who may walk more slowly than others or experience declining physical mobility. This article examines
the relationship between transit ridership and proximity to fixed-route transit stations using survey data for older adults
in Buffalo and Erie County, New York. Demographic and socio-economic characteristics—including age, sex, race, income, possessing
a driver’s license, frequency of leaving home, and personal mobility limitations—are tested but do not display, in bi-variate
analysis, statistically significant differences for transit riders versus non-transit riders. However, features of the built
environment—including distance (actual and perceived) between home and transit stop, transit service level, population density,
number of street intersections, metropolitan location, and neighborhood crime (property and violent) rate—display statistically
significant differences for transit riders versus non-transit riders. Both objective and perceived walking distances to access fixed-route transit show statistically significant differences between transit riders and non-transit
riders. Average walking distance from home to transit for non-transit riders—who mostly live in suburbs—is three times greater
than average walking distance between home and the nearest transit stop for transit riders—who mostly live in the central
city. When asked how near a bus stop is to their homes, transit riders slightly overestimate the actual distance, while non-transit
riders underestimate the distance. 相似文献
24.
Abstract In the early 1970s, Seattle Piers 90/91 were declared surplus federal property by the GSA. These obsolescent half‐mile‐long piers and their adjacent uplands were purchased by the Port of Seattle for redevelopment. This urban waterfront site of almost 200 acres presents the Port of Seattle with a number of severe planning problems. While it is the last large deep‐water site on Elliott Bay, it is also in a very sensitive location, since it is overlooked on two sides by vocal residential communities with a history of active intervention in development projects on visual and other environmental grounds. At Piers 90/91, public concerns over the visual effects of port redevelopment include: 1. nuisance effects of night‐operations lighting on adjacent hillside residences; 2. nighttime obstruction of distant views due to increased foreground illumination; 3. day and night view obstruction by tall structures such as container‐handling cranes; 4. alteration of the character of both day and nighttime views by new port facilities. As part of a program to study the effects of alternative redevelopment strategies for Piers 90/91, the Port has undertaken a through examination of the visual effects of different uses, their visual appropriateness, and the ways by which adverse visual effects can be mitigated. The results were incorporated into an environmental impact statement which documented compliance with the Seattle Shoreline Master Program and with view protection and glare provisions of the City's S.E.P.A. guidelines. A systematic Visual Resource Management (VRM) approach was successfully employed on this coastal zone project. Major elements included visibility mapping, key view selection, analysis of existing visual character, simulation of alternatives, assessment of relative visual compatibility, and determination of effective mitigation measures. Community involvement has also been a critical element in this approach to assessing and managing the visual effects of redevelopment in a major urban port. 相似文献
25.
A multinomial choice framework was used to analyze data from hypothetical storm forecast scenarios administered via mail survey to a random sample of U.S. Gulf Coast residents. Results indicate that the issuance of a mandatory evacuation notice and the presence of higher wind speeds had the largest influence on increasing the likelihood of evacuation. Age, race, disability, distance, and education were significant in explaining one's decision to wait relative to choosing to evacuate. Blacks and disabled individuals were strictly less likely to wait and more likely to make an immediate evacuation decision. Hurricane Katrina evacuees and those with an evacuation destination identified were also more likely to decide to evacuate, but were also more likely to wait before deciding. Results indicate that residents of mobile homes were more likely to either evacuate or wait before making a decision, but strictly less likely not to evacuate. Respondents very confident in being rescued were strictly more likely not to evacuate. Results indicate that not having an evacuation destination identified was the most influential factor regarding the likelihood of not knowing what choice to make. 相似文献
26.
Kalle Olli Annemarie Clarke sa Danielsson Juris Aigars Daniel J. Conley Timo Tamminen 《Journal of Marine Systems》2008,73(3-4):284
In many parts of the world coastal waters with anthropogenic eutrophication have experienced a gradual depletion of dissolved silica (DSi) stocks. This could put pressure on spring bloom diatom populations, e.g. by limiting the intensity of blooms or by causing shifts in species composition. In addition, eutrophication driven enhanced diatom growth is responsible for the redistribution of DSi from the water phase to the sediments, and changes in the growth conditions may be reflected in the sediment diatom stratigraphy.To test for changes in diatom communities we have analyzed four sediment cores from the Baltic Sea covering approximately the last 100 years. The sediment cores originate from the western Gulf of Finland, the Kattegat, the Baltic Proper and the Gulf of Riga. Three out of the four cores reveal only minor changes in composition of diatom assemblages, while the Gulf of Riga core contains major changes, occurring after the second World War. This area is set apart from the other Baltic Sea basins by a high frequency of low after spring bloom DSi concentrations (< 2 µmol L− 1) during a relatively well defined time period from 1991–1998. In 1991 to 1993 a rapid decline of DSi spring concentrations and winter stocks (down to 5 µmol L− 1) in the Gulf was preceded by exceptionally intense diatom spring blooms dominated by the heavily silicified species Thalassiosira baltica (1991–1992; up to 5.5 mg ww L− 1). T. baltica has been the principal spring bloom diatom in the Gulf of Riga since records began in 1975. DSi consumption and biomass yield experiments with cultured T. baltica suggest that intense blooms can potentially exhaust the DSi stock of the water column and exceed the annual Si dissolution in the Gulf of Riga. The phytoplankton time series reveals another exceptional T. baltica bloom period in 1981–1983 (up to 8 mg L− 1), which, however, took place before the regular DSi measurements. These periods may be reflected in the conspicuous accumulation of T. baltica frustules in the sediment core corresponding to ca. 1975–1985. 相似文献
27.
Daniel Ainalis Vincent Rouillard Michael Sek 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(6):765-783
This paper describes the application of a practical analytical technique based on the random decrement method to estimate the rigid sprung mass dynamic characteristics (frequency response function) of road vehicles using only vibration response data during constant-speed operation. A brief history and development of the random decrement technique is presented, along with a summary of work undertaken on optimal parameter selection to establish the random decrement signature. Two approaches to estimate the dynamic characteristics from the random decrement signature are described and evaluated. A custom, single-wheeled vehicle (physical quarter car) was commissioned to undertake a series of on-the-road experiments at various nominally constant operating speeds. The vehicle, also instrumented as an inertial profilometer, simultaneously measured the longitudinal pavement profile to establish the vehicle's actual dynamic characteristics during operation. The main outcome of the paper is that the random decrement technique can be used to provide accurate estimates of the sprung mass mode of the vehicle's dynamic characteristics for both linear and nonlinear suspension systems of an idealised vehicle. 相似文献
28.
Daniel Lindvai-Soos Martin Horn 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(7):1002-1027
In this article a novel vehicle dynamics control concept is designed for a vehicle equipped with wheel individual electric traction machines, electronically controlled brakes and semi-active suspensions. The suspension's cross-couplings between traction forces and vertical forces via anti-dive and anti-squat geometry is utilised in the control concept to improve driving comfort and driving stability. The control concept is divided into one main and two cascaded branches. The main controller consists of a multivariable vehicle dynamics controller and a control allocation scheme to improve the vehicle's driving comfort. The cascaded feedback loops maintain the vehicle's stability according to wheel slip and vehicle sideslip. The performance of the combined vehicle dynamics controller is compared to a standard approach in simulation. It can be stated that the controller piloting semi-active suspensions together with brake and traction devices enables a superior performance regarding comfort and stability. 相似文献
29.
Piyapong Jiwattanakulpaisarn Robert B. Noland Daniel J. Graham 《Transportation Research Part A: Policy and Practice》2010,44(4):265-280
While transport infrastructure investments have usually been viewed to have long-term impacts on employment, what is perhaps not immediately clear is the direction of causality. This paper has sought to disentangle the causal relationship between highway infrastructure and employment, using panel data for the 48 contiguous US states from 1984 to 1997. Of particular emphasis in this analysis is the sectoral differences in the causal and spatial effects of highway capacity expansions for employment growth in alternative sectors of the economy. The results indicate that lane-mile additions of own-state major highways could increase state employment growth in the services sector while reducing growth in manufacturing. However, the causal relationship is also found to work the other way around. That is, both the rapid growth in services employment and the slowdown in manufacturing jobs temporally lead to increases in roadway capacity of non-interstate major roads. Our analysis also shows that highway infrastructure could produce both positive and negative employment spillovers across states. We find that improvements in non-interstate major roads outside the state border are beneficial to the manufacturing sector which generally serves regional and national markets. For the services sector, however, employment gains from interstate highways in the same state may come at the expense of other states as there is clear evidence of negative employment spillovers from interstate lane-mile additions. 相似文献
30.
Julia A. Ekstrom Gloria T. Lau Daniel J. Spiteri Jack C. P. Cheng Kincho H. Law 《Coastal management》2013,41(5):457-473
Transitioning ocean governance into an integrated ecosystem-based approach requires improved knowledge of existing governance arrangements. This article presents a software tool, MINOE, to assist policymakers, scientists, and others involved in ecosystem-based management initiatives to navigate through management documents as they relate to a user-defined ecosystem. The tool uses a conceptually modeled ecosystem, defined by the user, and text analysis of a set of management-related documents to determine which ecosystem linkages are potentially acknowledged in the documents. For illustration, the set of documents included with MINOE currently (and used to demonstrate the software in this article) are laws and regulations from four geopolitical jurisdictions for the year 2006; however, users may also import other documents for a more tailored application. Features include an interactive matrix containing results about the set of management documents within the user's scope and scale of interest. In addition, MINOE includes metrics and visualization tools to synthesize information derived from the documents. The article presents the software tool, describes potential uses for the tool, and ends with a discussion of future work to expand the program. 相似文献