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121.
Cities worldwide are implementing modern transit systems to improve mobility in the increasingly congested metropolitan areas. Despite much research on the effects of such systems, a comparison of effects across transit modes and countries has not been studied comprehensively. This paper fills this gap in the literature by reviewing and comparing the effects obtained by 86 transit systems around the world, including Bus Rapid Transit (BRT), Light Rail Transit (LRT), metro and heavy rail transit systems. The analysis is twofold by analysing (i) the direct operational effects related to travel time, ridership and modal shifts, and (ii) the indirect strategic effects in terms of effects on property values and urban development. The review confirms the existing literature suggesting that BRT can attract many passengers if travel time reductions are significantly high. This leads to attractive areas surrounding the transit line with increasing property values. Such effects are traditionally associated with attractive rail-based public transport systems. However, a statistical comparison of 41 systems did not show significant deviations between effects on property values resulting from BRT, LRT and metro systems, respectively. Hence, this paper indicates that large strategic effects can be obtained by implementing BRT systems at a much lower cost.  相似文献   
122.
This paper presents a comprehensive review of the literature on off-peak hour deliveries (OPHD). The review identifies different approaches and policy levers used in the past, such as the laissez-faire approach, a road pricing approach, an incentives approach, and a regulatory approach. The paper also identifies different delivery reception schemes discussed in the literature. The authors complement the theory with a synthesis of pilot tests and the analysis of a set of interviews with practitioners (from the public sector and other organisations) in charge of OPHD programmes. The results from this review show the potential benefits that these programmes could bring about, the challenges faced in the early stages – along with potential solutions – and the significant progress that has been made in this domain in the last decade. According to the review, the results from the pilot tests tend to be positive, suggesting the importance of these programmes to reach more efficient and sustainable transportation systems.  相似文献   
123.
In this paper, a case study is carried out in Hong Kong for demonstration of the Transport Information System (TIS) prototype. A traffic flow simulator (TFS) is presented to forecast the short‐term travel times that can be served as a predicted travel time database for the TIS in Hong Kong. In the TFS, a stochastic deviation coefficient is incorporated to simulate the minute‐by‐minute fluctuation of traffic flows within the peak hour period. The purposes of the case study are: 1) to show the applicability of the TFS for larger‐scale road network; and 2) to illustrate the short‐term forecasting of path travel times in practice. The results of the case study show that the TFS can be applied to real network effectively. The predicted travel times are compared with the observed travel times on the selected paths for an OD pair. The results show that the observed path travel times fall in the 90% confidence interval of the predicted path travel times.  相似文献   
124.
This paper presents a detailed overview of CANDY, a catenary–pantograph dynamic interaction software. Authors describe the main key points of the formulation, focusing on its time-integration scheme, the pantograph and contact models as well as the solution of the initial equilibrium problem. Nonetheless one of the most important features of CANDY is its moving finite element mesh, which enables accurate results without excessive computational cost. The validation of the model against the European Standard EN 50318 and some conclusions and comments about the results of the benchmark are also included.  相似文献   
125.
This study presents an alternative method for estimating gravity models by multiple linear regression that is based on proxy variables, thus circumventing the endogeneity problems arising when least-squares estimators are used. The proxy variable approach generates consistent estimators for a gravity model without endogeneity bias. The presence of endogeneity is tested for using statistical tests developed specifically for our application.We conclude that proxy variables eliminate the endogeneity and produce consistent estimators in gravity models estimated using least squares. We also find, however, that endogeneity bias has no significant impact either on gravity model prediction or on urban transportation system planning processes based on such models.  相似文献   
126.
A multiproxy study of the sedimentary record carried out on gravity core CGPL00-1 retrieved from the outer Galician continental shelf (NW of Spain) has allowed us to establish the main climate fluctuations affecting the region during the Upper Holocene. Grain size, TOC, C/N ratio, biogenic opal and planktonic foraminifera are the main analysed parameters. Lithology and grain size distribution lead to identify two sedimentary sequences: a lower half mainly composed by glauconitic sand and a muddy upper half. A chronology has been established based on three AMS radiocarbon ages, 907 cal. BC, 898 cal. BC and 1399 AD, and the aforementioned sedimentary sequences. The obtained radiocarbon ages are the first dated sediment samples for the Galician continental shelf. Geochemical markers show different trends in both sequences: low and/or fluctuating values in the sandy sequence and high and relatively constant values in the upper muddy sequence. The whole sandy interval is interpreted to be a nearly instantaneous deposit from a distal storm ebb current. The muddy interval was deposited in a stable and low-energy marine environment, similar to that found on the present outer shelf. The shift from a storm-dominated shelf to a low-energy environment took place synchronous with the Subboreal/Subatlantic transition, when an increase in storminess appears related to climatic instability. Transitional planktonic foraminiferal assemblage dominates the whole record, although a change to more abundant cold water species at 1420 AD, may relate to an intense upwelling pulse, probably reinforced by colder atmospheric temperatures during the Little Ice Age (LIA). Despite the presence of an upwelling regime since 1420 AD, lesser amount of opal has accumulated in the outer shelf due to enhanced offshore transport and stronger remineralization.  相似文献   
127.
Though seaweed consumption is growing steadily across Europe, relatively few studies have reported on the quantities of heavy metals they contain and/or their potential effects on the population's health. This study focuses on the first topic and analyses the concentrations of six typical heavy metals (Cd, Pb, Hg, Cu, Zn, total As and inorganic As) in 52 samples from 11 algae-based products commercialised in Spain for direct human consumption (Gelidium spp.; Eisenia bicyclis; Himanthalia elongata; Hizikia fusiforme; Laminaria spp.; Ulva rigida; Chondrus crispus; Porphyra umbilicales and Undaria pinnatifida).Samples were ground, homogenised and quantified by atomic absorption spectrometry (Cu and Zn by flame AAS; Cd, Pb and total As by electrothermal AAS; total mercury by the cold vapour technique; and inorganic As by flame-hydride generation). Accuracy was assessed by participation in periodic QUASIMEME (Quality Assurance of Information in Marine Environmental Monitoring in Europe) and IAEA (International Atomic Energy Agency) intercalibration exercises. To detect any objective differences existing between the seaweeds' metal concentrations, univariate and multivariate studies (principal component analysis, cluster analysis and linear discriminant analysis) were performed. It is concluded that the Hizikia fusiforme samples contained the highest values of total and inorganic As and that most Cd concentrations exceeded the French Legislation. The two harvesting areas (Atlantic and Pacific oceans) were differentiated using both univariate studies (for Cu, total As, Hg and Zn) and a multivariate discriminant function (which includes Zn, Cu and Pb).  相似文献   
128.
Most of the information necessary for driving a vehicle is regarded as visual information. In spite of its importance, visibility conditions at the time of a crash are often not documented at a high level of detail. Past studies have not examined the quantified values of visibility and its association with crashes. The current study merged data collected from the National Oceanic and Atmospheric Administration (NOAA) with 2010–2012 Florida crash data. From the thousands of logged weather events compiled by the NOAA, the researchers isolated periods of normal visibility and comparable periods of reduced visibility in a matched-pairs study. The NOAA data provided real visibility score based on the spatiotemporal data of the crashes. Additionally, the crash data, obtained from Roadway Information Database (RID), contains several geometric and traffic variables that allow for effects of factors and visibility. The study aims to associate crash occurrence under different levels of visibility with factors included in the crash database by developing ordinal logistic regression. The intent is to observe how different visibility conditions contribute to a crash occurrence. The findings indicate that the likelihood of a crash increase during periods of low visibility, despite the tendency for less traffic and for lower speeds to prevail during these times. The findings of this study will add valuable knowledge to the realm of the impact of visibility in the way of using and designing appropriate countermeasures.  相似文献   
129.
This article proposes a model for analysing the modal choice of travellers making inter-urban journeys. Discrete choice models with systematic and random tastes variation were applied to find the most relevant variables for encouraging the use of public transport by bus rather than private car. This research follows on from the results of previous user satisfaction studies on inter-urban bus services in the province of Burgos (Spain). Willingness to pay is also estimated for time savings or other improvements in the bus service.The results indicate that, in general, improvements in the journey time or the number of daily journeys are valued less by inter-urban bus users than they are by car or railway users. The type of bus and its characteristics are evaluated as a function of the distance travelled and result in very small values for this variable. Contrary to what is often reported in satisfaction surveys, the journey cost is found to be relevant when choosing which mode of transport to use, but the most important variable is journey time. Little value is placed on the features of the bus, except on long distance journeys.Finally, a methodology differentiating four hierarchical groups is presented for comparing the results of the relevant variables in demand and satisfaction models. Some only improve perception rather than encourage new users, while others increase take-up but do not improve the image of the service.  相似文献   
130.
Transit operators face a difficult fiscal environment and an imperative to contribute to urban sustainability. Under these circumstances, operators must find innovative ways to make public transportation attractive to broader segments of the public, while simultaneously trying to raise revenue to reduce reliance on public subsidies. Development of commercial partnerships is seen as a promising way to achieve these goals. Previous research has examined the potential of using geodemographics to assist transit agencies in the task of identifying potential partners for developing mutually beneficial commercial agreements. In this paper we describe an approach to model isoexposure to transit users as a tool to assess market potential. The approach is based on the analysis of walking behavior of transit users, and specifically distance walked at the end of their transit trip. Spatial modeling is used to geographically project estimates of walking distance for a desired demographic profile at a specific transit facility. After expanding the estimates using sample weights, overlays of these estimates can be used to generate variations in exposure to transit travelers at different locations in space. The approach is demonstrated using the case of Metro users in Montreal, Canada. The case study demonstrates the use of isoexposure profiles as a novel approach to generate marketing intelligence. This should be of interest to transit agencies and businesses interested in developing partnerships.  相似文献   
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