共查询到6条相似文献,搜索用时 15 毫秒
1.
Electric Freight Vehicles (EFVs) are a promising and increasingly popular alternative to conventional trucks in urban pickup/delivery operations. A key concerned research topic is to develop trip-based Tank-to-Wheel (TTW) analyses/models for EFVs energy consumption: notably, there are just a few studies in this area. Leveraging an earlier research on passenger electric vehicles, this paper aims at filling this gap by proposing a microscopic backward highly-resolved power-based EFVs energy consumption model (EFVs-ECM). The model is estimated and validated against real-world data, collected on a fleet of five EFVs in the city centre of Rome, for a total of 144 observed trips between subsequent pickup/delivery stops. Different model specifications are tested and contrasted, with promising results, in line with previous findings on electric passenger vehicles. 相似文献
2.
Stated choice experiments have proven to be a powerful tool in eliciting preferences across a broad range of choice settings.
This paper outlines the elements of a group-based experiment designed for interdependent urban freight stakeholders, along
with the procedure to administer the questionnaire sequentially. The focus is on the design of a computer-assisted personal
survey instrument and the value in disseminating the details of a new approach to design and collect stated choice data for
interacting agents. The paper also discusses how to specify a reference alternative, and then how to recruit appropriate real-market
or representative decision-making group members to participate in a subsequent phase of the survey, which incorporates the
reference alternative and contextual information from an initial phase. The empirical strategy, set out in some detail, provides
a new framework within which to understand more fully the role that specific attributes, such as variable user charges, influencing
freight distribution chains might play, and who in the supply chain is affected by specific attributes in terms of willingness
to pay for the gains in distribution efficiency.
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Andrew CollinsEmail: |
3.
A sequential approach to exploiting the combined strengths of SP and RP data: Application to freight shipper choice 总被引:2,自引:0,他引:2
The possibility of and procedure for pooling RP and SP data have been discussed in recent research work. In that literature, the RP data has been viewed as the yardstick against which the SP data must be compared. In this paper we take a fresh look at the two data types. Based on the peculiar strengths and weaknesses of each we propose a new, sequential approach to exploiting the strengths and avoiding the weaknesses of each data source. This approach is based on the premise that SP data, characterized by a well-conditioned design matrix and a less constrained decision environment than the real world, is able to capture respondents' tradeoffs more robustly than is possible in RP data. (This, in turn, results in more robust estimates of share changes due to changes in independent variables.) The RP data, however, represent the current market situation better than the SP data, hence should be used to establish the aggregate equilibrium level represented by the final model. The approachfixes the RP parameters for independent variables at the estimated SP parameters but uses the RP data to establish alternative-specific constants. Simultaneously, the RP data are rescaled to correct for error-in-variables problems in the RP design matrixvis-à- vis the SP design matrix. All specifications tested are Multinomial Logit (MNL) models.The approach is tested with freight shippers' choice of carrier in three major North American cities. It is shown that the proposed sequential approach to using SP and RP data has the same or better predictive power as the model calibrated solely on the RP data (which is the best possible model for that data, in terms of goodness-of-fit figures of merit), when measured in terms of Pearson's Chi-squared ratio and the percent correctly predicted statistic. The sequential approach is also shown to produce predictions with lower error than produced by the more usual method of pooling the RP and SP data. 相似文献
4.
According to the Belgrade Master Plan for 2021, the public transportation system for the city and its region will include three rail modes: a modernized existing tramway, regional rail, and a new light rail transit (LRT) mode. In the coming years all three rail modes should be developed simultaneously and in a coordinated manner. The introduction of LRT is to be realized in several phases, and its first line will partially follow the alignment of an existing tramway line. As the present tramway vehicles are obsolete, new rolling stock must be designed and purchased to be compatible with many of the elements of the LRT. Ways to adjust the new tramways to the LRT rolling stock represent the central topic of this paper. The basic technical and operating characteristics of the new tramway are defined with respect to their required compatibility with the LRT stock and infrastructure. 相似文献
5.
As goods movement continues to increase it is expected to outpace infrastructure capacity in the United States. Moving a larger share of goods by rail rather than truck is a potentially cost effective part of a solution. Freight rail not only offers a substitute for truck trips but is a cleaner, more energy efficient, and safer alternative. Recently a number of private freight rail projects have received public funding. The public funds are aimed at increasing freight rail capacity with the goal of diverting some goods currently moved by truck to rail. While the benefits of moving goods by rail are relatively clear, it is unclear if public decision makers can effectively identify strategic rail investments that will achieve their policy goals. This study critically examines the analytical methods, models, and data that are commonly used to support decisions to provide public funds for private freight rail projects. This is accomplished through a case study of California’s Trade Corridors Improvement Fund program which provided $680 million for 11 freight rail projects. The study’s contributions include identifying critical analytical flaws and challenges affecting the benefit estimates that public funding decisions rely on. Improvements to current evaluation methods are also identified as are regulatory reforms and policy interventions that may offer more effective and reliable outcomes. 相似文献
6.
Travel information continues to receive significant attention in the field of travel behaviour research, as it is expected to help reduce congestion by directing the network state from a user equilibrium towards a more efficient system optimum. This literature review contributes to the existing literature in at least two ways. First, it considers both the individual perspective and the network perspective when assessing the potential effects of travel information, in contrast to earlier studies. Secondly, it highlights the role of bounded rationality as well as that of non-selfish behaviour in route choice and in response to information, complementing earlier reviews that mostly focused on bounded rationality only. It is concluded that information strategies should be tailor-made to an individual's level of rationality as well as level of selfishness in order to approach system-optimal conditions on the network level. Moreover, initial ideas and future research directions are provided for assessing the potential of travel information in order to improve network efficiency of existing road networks. 相似文献