Vol 17 No 2 (2017)
2017-04-01
Vol 17 No 2 (2017)
2017-04-01
Articles
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Moving walkways (MW) have been imagined as a possible means of transport since the late 19th century, and this system has fascinated urban planners and engineers ever since. Contrary to what has been imagined, moving walkways are only used in transportation hub corridors, and not as a main transport mode in city centers. Today however, MWs are receiving increasing attention as a possible solution to congestion and pollution, as well as a catalyst for soft mobility. This paper explores the role of moving walkways as a transport system, and it presents an optimized design of a network of MWs in a city center. We review historical MWs, current installations and future possibilities, using different perspectives, from geography to urban planning to transport engineering. We discuss the way in which MWs influence how people inhabit the urban space, and we review this system in the context of history of urban planning. Then, we describe a technological development called accelerating moving walkways (AMW), i.e. MWs able to reach a higher speed than traditional ones. We develop an optimization framework to design a network of AMWs, and we apply it to a real case study. The results of the network design are a reference useful to discuss the feasibility of the system starting from an engineering perspective. We conclude that the use of MWs can facilitate the flexibility and spontaneity typical of pedestrian movements, and this system could be integrated in the mix of urban transport modes in city centers.
Moving walkways (MW) have been imagined as a possible means of transport since the late 19th century, and this system has fascinated urban planners and engineers ever since. Contrary to what has been imagined, moving walkways are only used in transportation hub corridors, and not as a main transport mode in city centers. Today however, MWs are receiving increasing attention as a possible solution to congestion and pollution, as well as a catalyst for soft mobility. This paper explores the role of moving walkways as a transport system, and it presents an optimized design of a network of MWs in a city center. We review historical MWs, current installations and future possibilities, using different perspectives, from geography to urban planning to transport engineering. We discuss the way in which MWs influence how people inhabit the urban space, and we review this system in the context of history of urban planning. Then, we describe a technological development called accelerating...
Moving walkways (MW) have been imagined as a possible means of transport since the late 19th century, and this system has fascinated urban planners and engineers ever since. Contrary to what has been imagined, moving walkways are only used in transportation hub corridors, and not as a main...
Riccardo Scarinci, Farzaneh Bahrami, Andr´e Ourednik, Michel Bierlaire -
Whether vertical separation of the rail industry creates demonstrable performance and efficiency gains is an issue of ongoing economic analysis and public policy debate. To assist in consideration of the merits and disbenefits of vertical separation this paper provides a summary of the different studies that have been undertaken to gauge the effects of vertical separation on the rail industry, and analyses and codifies the main findings of this research. The evidence indicates that whether separation will improve efficiency of a jurisdiction’s rail industry, and the extent to which this will occur, depends upon a number of specific conditions including what range of services are being provided – that is, passenger and/or bulk or general freight –the intensity of track use, and the extent to which inter-modal competition exists. The research highlights the merits of undertaking preliminary analysis of the characteristics of a jurisdiction’s rail sector before initiating structural reform of this nature.
Whether vertical separation of the rail industry creates demonstrable performance and efficiency gains is an issue of ongoing economic analysis and public policy debate. To assist in consideration of the merits and disbenefits of vertical separation this paper provides a summary of the different studies that have been undertaken to gauge the effects of vertical separation on the rail industry, and analyses and codifies the main findings of this research. The evidence indicates that whether separation will improve efficiency of a jurisdiction’s rail industry, and the extent to which this will occur, depends upon a number of specific conditions including what range of services are being provided – that is, passenger and/or bulk or general freight –the intensity of track use, and the extent to which inter-modal competition exists. The research highlights the merits of undertaking preliminary analysis of the characteristics of a jurisdiction’s rail sector before initiating...
Whether vertical separation of the rail industry creates demonstrable performance and efficiency gains is an issue of ongoing economic analysis and public policy debate. To assist in consideration of the merits and disbenefits of vertical separation this paper provides a summary of the...
Malcolm Abbott, Bruce Cohen -
The paper proposes a methodology for freight corridor performance monitoring that is suitable for sustainability assessments. The methodology, initiated by the EU-funded project SuperGreen, involves the periodic monitoring of a standard set of transport chains along the corridor in relation to a number of Key Performance Indicators (KPIs). It consists of decomposing the corridor into transport chains, selecting a sample of typical chains, assessing these chains through a set of KPIs, and then aggregating the chain-level KPIs to corridor-level ones using proper weights. A critical feature of this methodology concerns the selection of the sample chains and the calculation of the corresponding weights. After several rounds of development, the proposed methodology suggests a combined approach involving the use of a transport model for sample construction and weight calculation followed by stakeholder refinement and verification. The sample construction part of the methodology was tested on GreCOR, a green corridor project in the North Sea Region, using the Danish National Traffic Model as the principal source of information for both sample construction and KPI estimation. The results show that, to the extent covered by the GreCOR application, the proposed methodology can effectively assess the performance of a freight transport corridor. Combining the model-based approach for the sample construction with the study-based approach for the estimation of chain-level indicators exploits the strengths of each method and avoids their weaknesses. Possible improvements are also suggested by the paper.
The paper proposes a methodology for freight corridor performance monitoring that is suitable for sustainability assessments. The methodology, initiated by the EU-funded project SuperGreen, involves the periodic monitoring of a standard set of transport chains along the corridor in relation to a number of Key Performance Indicators (KPIs). It consists of decomposing the corridor into transport chains, selecting a sample of typical chains, assessing these chains through a set of KPIs, and then aggregating the chain-level KPIs to corridor-level ones using proper weights. A critical feature of this methodology concerns the selection of the sample chains and the calculation of the corresponding weights. After several rounds of development, the proposed methodology suggests a combined approach involving the use of a transport model for sample construction and weight calculation followed by stakeholder refinement and verification. The sample construction part of the methodology was...
The paper proposes a methodology for freight corridor performance monitoring that is suitable for sustainability assessments. The methodology, initiated by the EU-funded project SuperGreen, involves the periodic monitoring of a standard set of transport chains along the corridor in relation to...
George Panagakos, Harilaos N. Psaraftis -
According to random utility theory, there is no clear distinction between the utility inferred from observed choices (decision utility), the experienced outcome of decision makers’ (experienced utility) or their retrospective evaluation (remembered utility). While empirical experiments have shown that decision utility and remembered utility do not perfectly coincide, little is known regarding the magnitude of this discrepancy, especially in the transport field. Using a cross-sectional travel survey, the objective of this paper is to quantify the relationship between commuters’ stated choice satisfaction (a proxy for remembered utility) and the Logsum function of the utility of all available modes of transport (decision utility). This is of tremendous importance, as implemented transport policy measures, which aim to increase the overall decision makers’ utility, may have low impact on their satisfaction level and thus be ineffective. Results indicate that the utility Logsum is associated with respondents’ commuting satisfaction. However, context specificities have an important impact on this association.
According to random utility theory, there is no clear distinction between the utility inferred from observed choices (decision utility), the experienced outcome of decision makers’ (experienced utility) or their retrospective evaluation (remembered utility). While empirical experiments have shown that decision utility and remembered utility do not perfectly coincide, little is known regarding the magnitude of this discrepancy, especially in the transport field. Using a cross-sectional travel survey, the objective of this paper is to quantify the relationship between commuters’ stated choice satisfaction (a proxy for remembered utility) and the Logsum function of the utility of all available modes of transport (decision utility). This is of tremendous importance, as implemented transport policy measures, which aim to increase the overall decision makers’ utility, may have low impact on their satisfaction level and thus be ineffective. Results indicate that the utility Logsum...
According to random utility theory, there is no clear distinction between the utility inferred from observed choices (decision utility), the experienced outcome of decision makers’ (experienced utility) or their retrospective evaluation (remembered utility). While empirical experiments have...
François Sprumont, Paola Astegiano, Francesco Viti -
The implementation of travel time reliability (TTR) in route choice behaviour is still not very common in transport models, especially not in a public transport context. The reasons probably are that it is difficult to measure and that there is no agreement how it best can be represented in utility functions. Typically, it is represented by a standard deviation, however, particularly in public transport choices it is more likely that travellers think about the consequences of unreliability in travel times in terms of buffer times. This paper contributes to the literature by comparing five different model specifications of TTR in public transport route choices that are either based on standard deviations or on buffer time indicators. The models are estimated from choices observed in a stated choice experiment. To address heterogeneity, a latent class model is estimated. The results suggest that the reliability buffer time indicator outperforms the standard deviation indicator. Furthermore, the reliability buffer time parameter is only statistically significant in two of the four classes. The other two classes are particularly sensitive to making transfers and to low frequencies of public transport services, suggesting different strategies to deal with TTR.
The implementation of travel time reliability (TTR) in route choice behaviour is still not very common in transport models, especially not in a public transport context. The reasons probably are that it is difficult to measure and that there is no agreement how it best can be represented in utility functions. Typically, it is represented by a standard deviation, however, particularly in public transport choices it is more likely that travellers think about the consequences of unreliability in travel times in terms of buffer times. This paper contributes to the literature by comparing five different model specifications of TTR in public transport route choices that are either based on standard deviations or on buffer time indicators. The models are estimated from choices observed in a stated choice experiment. To address heterogeneity, a latent class model is estimated. The results suggest that the reliability buffer time indicator outperforms the standard deviation indicator....
The implementation of travel time reliability (TTR) in route choice behaviour is still not very common in transport models, especially not in a public transport context. The reasons probably are that it is difficult to measure and that there is no agreement how it best can be represented in...
Andele B. Swierstra, Rob van Nes, Eric J.E. Molin -
This paper explores the relationship between output specialisation, diversification, size and technical efficiency in ports. Using a sample of Spanish port authorities observed over the period 1993-2012, we calculate a normalised Herfindahl-Hirschman index of overall specialisation and indices of relative specialisation in the individual cargoes. An output distance frontier is estimated using non-parametric Data Envelopment Analysis techniques to calculate technical efficiency. These efficiency scores are then used to test that relationship with a bootstrapped truncated regression. We find that both overall and relative output specialisation have a positive influence on technical efficiency. Moreover, the positive effects of specialisation on technical efficiency is reinforced for larger ports, which are in a better position to take advantage of economies of scale and which can also attract different types of cargo (enjoying also economies of scope) and therefore protect themselves from adverse demand conditions. Our results underline the trade-off for smaller port authorities between efficiency gains from specialisation and their vulnerability to market conditions for their main output.
This paper explores the relationship between output specialisation, diversification, size and technical efficiency in ports. Using a sample of Spanish port authorities observed over the period 1993-2012, we calculate a normalised Herfindahl-Hirschman index of overall specialisation and indices of relative specialisation in the individual cargoes. An output distance frontier is estimated using non-parametric Data Envelopment Analysis techniques to calculate technical efficiency. These efficiency scores are then used to test that relationship with a bootstrapped truncated regression. We find that both overall and relative output specialisation have a positive influence on technical efficiency. Moreover, the positive effects of specialisation on technical efficiency is reinforced for larger ports, which are in a better position to take advantage of economies of scale and which can also attract different types of cargo (enjoying also economies of scope) and therefore protect...
This paper explores the relationship between output specialisation, diversification, size and technical efficiency in ports. Using a sample of Spanish port authorities observed over the period 1993-2012, we calculate a normalised Herfindahl-Hirschman index of overall specialisation and indices...
Beatriz Tovar, Alan Wall