3,827 research outputs found
How to monitor sustainable mobility in cities? Literature review in the frame of creating a set of sustainable mobility indicators
The role of sustainable mobility and its impact on society and the environment is evident and recognized worldwide. Nevertheless, although there is a growing number of measures and projects that deal with sustainable mobility issues, it is not so easy to compare their results and, so far, there is no globally applicable set of tools and indicators that ensure holistic evaluation and facilitate replicability of the best practices. In this paper, based on the extensive literature review, we give a systematic overview of relevant and scientifically sound indicators that cover different aspects of sustainable mobility that are applicable in different social and economic contexts around the world. Overall, 22 sustainable mobility indicators have been selected and an overview of the applied measures described across the literature review has been presented
Assessing temporary speed restrictions and associated unavailability costs in railway infrastructure
This paper analyses the occurrence of temporary speed restrictions in railway infrastructure associated with railway track geometry degradation. A negative binomial regression model is put forward to estimate the expected number of temporary speed restrictions, controlling for the main quality indicators of railway track geometry degradation and for the maintenance and renewal actions/decisions. The prediction of temporary speed restrictions provides a quantitative way to support the assessment of unavailability costs to railway users. A case study on the LisbonâOporto Portuguese line is explored, comparing three statistical models: the Poisson, the âover-dispersedâ Poisson and the proposed negative binomial regression. Main findings suggest that the main quality indicators for railway track geometry degradation are statistically significant variables, apart from the maintenance and renewal actions. Finally, a discussion on the impacts of the unavailability costs associated with temporary speed restrictions is also provided in a regulated railway context.info:eu-repo/semantics/acceptedVersio
The Relationship between Liberalisation in the Logistics Sector and Trade Facilitation
This study demonstrates that the improvement of the performance of logistics services through domestic liberalisation may generate a virtuour cycle, whereby international trade is increased and the this, in turn, may increase the deman for logistics services.Liberalisation, Logistics Sector, Trade Facilitation
The impacts on freight train operational performance of new rail infrastructure to segregate passenger and freight traffic
Rail freight has an important role to play in improving the resource efficiency and sustainability of freight transport within the supply chain. The British rail network has seen considerable growth of both freight and passenger activity in the last 20 years, leading to concerns about its capacity to absorb continued growth. A number of infrastructure initiatives focused on increasing capacity and reducing conflicts have been implemented. This includes the North Doncaster Chord, opened in June 2014 primarily to provide a more direct route from the port of Immingham to the major Aire Valley power stations (i.e. Drax, Eggborough and Ferrybridge).
The paper analyses the freight impacts of the new chord, focusing on three key operational measures (i.e. train routing, scheduled journey times and train punctuality) during 10-week survey periods before and after the opening of the chord. The analysis is based on real-time data relating to coal and biomass trains operating between Immingham and the three power stations. This is a novel approach as the data have been made publicly available only recently, allowing a detailed investigation of the flows on this corridor at a highly disaggregated level. The use of this empirical method to assess the detailed rail freight operational impacts is an important element in the process of evaluating the effects of network enhancement. The results demonstrate improvements in each of the three operational measures, but also reveal a situation considerably more complex than that suggested by the published material relating to the justification for this new infrastructure
Railway operations, time-tabling and control
This paper concentrates on organising, planning and managing the train movement in a network. The three classic management levels for rail planning, i.e., strategic, tactical and operational, are introduced followed by decision support systems for rail traffic control. In addition, included in this paper are discussions on train operating forms, railway traffic control and train dispatching problems, rail yard technical schemes and performance of terminals, as well as timetable design. A description of analytical methods, simulation techniques and specific computer packages for analysing and evaluating the behaviour of rail systems and networks is also provided
National freight transport planning: towards a Strategic Planning Extranet Decision Support System (SPEDSS)
This thesis provides a `proof-of-concept' prototype and a design architecture for a
Object Oriented (00) database towards the development of a Decision Support
System (DSS) for the national freight transport planning problem. Both governments
and industry require a Strategic Planning Extranet Decision Support System
(SPEDSS) for their effective management of the national Freight Transport Networks
(FTN).
This thesis addresses the three key problems for the development of a SPEDSS to
facilitate national strategic freight planning: 1) scope and scale of data available and
required; 2) scope and scale of existing models; and 3) construction of the software.
The research approach taken embodies systems thinking and includes the use of:
Object Oriented Analysis and Design (OOA/D) for problem encapsulation and
database design; artificial neural network (and proposed rule extraction) for
knowledge acquisition of the United States FTN data set; and an iterative Object
Oriented (00) software design for the development of a `proof-of-concept'
prototype. The research findings demonstrate that an 00 approach along with the use
of 00 methodologies and technologies coupled with artificial neural networks
(ANNs) offers a robust and flexible methodology for the analysis of the FTN problem
domain and the design architecture of an Extranet based SPEDSS.
The objectives of this research were to: 1) identify and analyse current problems and
proposed solutions facing industry and governments in strategic transportation
planning; 2) determine the functional requirements of an FTN SPEDSS; 3) perform a
feasibility analysis for building a FTN SPEDSS `proof-of-concept' prototype and
(00) database design; 4) develop a methodology for a national `internet-enabled'
SPEDSS model and database; 5) construct a `proof-of-concept' prototype for a
SPEDSS encapsulating identified user requirements; 6) develop a methodology to
resolve the issue of the scale of data and data knowledge acquisition which would act
as the `intelligence' within a SPDSS; 7) implement the data methodology using
Artificial Neural Networks (ANNs) towards the validation of it; and 8) make recommendations for national freight transportation strategic planning and further
research required to fulfil the needs of governments and industry.
This thesis includes: an 00 database design for encapsulation of the FTN; an
`internet-enabled' Dynamic Modelling Methodology (DMM) for the virtual
modelling of the FTNs; a Unified Modelling Language (UML) `proof-of-concept'
prototype; and conclusions and recommendations for further collaborative research
are identified
Issues on simulation of the railway rolling stock operation process â a system and literature review
Railway traffic simulation, taking into account operation and maintenance conditions, is not a new issue in the literature. External effects in such networks (eg. level crossings) were not taken into account in studies. The used models do not take into account sufficiently the process of degradation and recovery of the network. From the technical side, currently carried out simulations are made using similar approaches and techniques as in the initial stage of research. Well-established work in this area could be the basis for evaluation of new solutions. However, the progress in simulation tools during the last years, especially in performance and programming architecture, attempt to create a modern simulation tool. In the paper were presented the main assumptions for the evaluated event-based simulation method, with application to stiff-track transportation network
Complex delay dynamics on railway networks: from universal laws to realistic modelling
Railways are a key infrastructure for any modern country. The reliability and
resilience of this peculiar transportation system may be challenged by
different shocks such as disruptions, strikes and adverse weather conditions.
These events compromise the correct functioning of the system and trigger the
spreading of delays into the railway network on a daily basis. Despite their
importance, a general theoretical understanding of the underlying causes of
these disruptions is still lacking. In this work, we analyse the Italian and
German railway networks by leveraging on the train schedules and actual delay
data retrieved during the year 2015. We use {these} data to infer simple
statistical laws ruling the emergence of localized delays in different areas of
the network and we model the spreading of these delays throughout the network
by exploiting a framework inspired by epidemic spreading models. Our model
offers a fast and easy tool for the preliminary assessment of the
{effectiveness of} traffic handling policies, and of the railway {network}
criticalities.Comment: 32 pages (with appendix), 28 Figures (with appendix), 2 Table
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