A trip chain order model for simulating urban freight restocking

This paper proposes a trip chain order model for simulating retailer restocking within urban and metropolitan area. It is part of the general modelling system developed by the authors for simulating urban freight demand which considers both demand and logistic sub-systems. The former allows us to obtain the freight Origin-Destination (OD) matrices in quantities and deliveries per transport service type, time slice and vehicle type. The latter allows us to obtain the vehicle OD matrices according to the journey characteristics (i.e. number and sequence of delivery points) in order to restock economic activities located within the study area. This approach, known in literature as tour-based approach, aims at reproducing the choice structure of the restocking process and the sequence of delivery points (stops) for vehicle journeys, considering dependences existing among subsequent trips of the same journey. It implies that each destination zone to be delivered is chosen depending on the previous and the next destination ones. The logistic subsystem of the proposed modelling system can be divided in two parts: the first which defines the trip chain order (i.e. the number of deliveries made during a tour); the second one which considers the choice of the stop locations. This paper focuses on the specification and calibration of a trip chain order model using data collected in the city centre of Rome

Activity location and mobility costs

The paper fits into the general themes of land use - transport planning (Nuzzolo and Coppola, 2008a and 2008b) and accessibility (Geurs and van Wee 2004) in urban areas. It's widely recognized in academia the need for integration between mobility and land use policies in accordance with the objectives of environmental sustainability and quality of life in urban areas (Nuzzolo and Coppola, 2007; te Brömmelstroet and Bertolini, 2011). Furthermore, in recent years travel behaviours are changing in urban areas due to the increase in oil prices, the recession of Western economies, the resulting lack of financial resources for public transport subsidies. For this reasons, technicians and scientists are trying to find solutions in the short and long term to make existing transport system more efficient. In this sense the search for integrated solutions including systems engineering, transport and urban planning is a priority not only in the scientific debate but also in the operative field. Despite an extensive literature on the land use-transport interaction has been produced, simple tools for land - use transport integrated planning are not as much used; in particular tools that can support the choices of location of new activities in the definition of urban or regional plans are not widely applied (Hull et al. 2012). According to this premise, the goal of the work is to develop a tool to support the choices of activities location, which is based on accessibility and transport costs indicators. Assuming that one of the goal of integrated land use – transport planning is the minimization of generalized transportation costs (Nuzzolo and Coppola, 2010), in compliance with the objectives of environmental sustainability and quality of life, the tool computes the “access cost” of activities, providing an estimation in monetary terms of the advantages and disadvantages of locating an activity in a particular zone of the urban area; the tool provide

Urban from and sustainability: modelling evidences from the empirical case study of RomeE

It is widely accepted that a connection exists between the shape, size and density of an urban area and its sustainability. However, consensus is lacking about the extent and characteristics of this relationship. Certain urban forms appear to be more sustainable in some respects, for example in reducing travel, but unfavourable in other aspects, as the environmental quality or social inequalities; furthermore, some forms may be sustainable locally, but not at the city wide scale (Burton et al. 2013). A number of empirical studies dealing with the influence of urban form on sustainability has not been conclusive and comes out with mixed outcomes. In order to provide empirical insights to this debate, this study investigates the relation between urban form and sustainability in terms of economic, social and environmental characteristics of the transport-land use integrated system, by comparing three different urban forms: compact, TOD and sprawl. The main research question is: does urban form, in terms of density and distribution of activities, impact the sustainability levels of urban areas? To give an answer to this question, the paper proposes a methodology for assessing urban forms, based on a system of Land-Use and Transport Interactions (LUTI) models. This has been designed and applied able to simulate the behaviour of both dwellers and transport users and how they react to changing conditions. A system of indicators has been then set up to systematically test and compare three urban scenarios, which differ in terms of density and distribution of activities and to assess to what extent different urban structures achieve or not sustainability in terms of economic, environmental and social impacts. More details are provided in the methodological section. © AET 2014 and contributors 2 This study presents some innovations points with regard to the existing literature. First, while already existing studies mainly focus of the assessment on a single urban form (with the exception of some more recent studies, Echenique et al., 2012), in this study we compare three urban structures. An additional difference with present literature is that most studies focus on small scale and local factors influencing travel behaviour and its consequence on sustainability level, while in this research we analyse the interaction between urban form and sustainable travel behaviour at the city wide scale. Finally, another novelty regards a specific application of utility based models, which are usually used for simulate the LUT system performance in terms of transport network speed or congestion. In this study we instead integrate them in a scenario analysis and in particular addressing sustainability and equity issues as managing the side effects of growth such as sprawl, congestion, housing affordability, pollution, energy consumption and loss of open spaces. In this way, we do not examine the effect of urban form only by parameter of travel (distance, time, frequency), but we propose a more complete sustainability assessments. Nevertheless, it is important to stress that in this study we do not take into account health and well-being aspects of sustainability, putting this focus off at future steps of the research. The paper is organized as follows. In Section 2 we refer to the existing literature and to the debate on the relations between urban form and sustainability. Section 3 describes the research design and in particular the system of models and the assessment indicators system. In Section 4 we discuss the results of the application to the empirical case study of Rome. Conclusions are drawn in Section 5

Special issue on dynamic models serving real-time urban transport operations

ABSTRACTIn the era of intelligent transportation systems, there is an increasing need of developing dynamic transport models to improve the realism of simulations, aiming to higher efficiency of ne..

A Subjective Optimal Strategy for Transit Simulation Models

A behavioural modelling framework with a dynamic travel strategy path choice approach is presented for unreliable multiservice transit networks. The modelling framework is especially suitable for dynamic run-oriented simulation models that use subjective strategy-based path choice models. After an analysis of the travel strategy approach in unreliable transit networks with the related hyperpaths, the search for the optimal strategy as a Markov decision problem solution is considered. The new modelling framework is then presented and applied to a real network. The paper concludes with an overview of the benefits of the new behavioural framework and outlines scope for further research. Document type: Articl

Editorial

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bus travel time variability some experimental evidences

Abstract Bus travel time analysis is essential for transit operation planning. Then, this topic obtained large attention in transport engineering literature and several methods have been proposed for investigating its variability. Nowadays, the availability of large data quantities through automated monitoring allows more in-depth this phenomenon to be pointed out with new experimental evidence. The paper presents the results of some analyses carried out using automatic vehicle location (AVL) data of bus lines and automated vehicle counter (AVC) data on some corridors in the urban area of Rome where the bus services are mixed with other traffic and travel times are subject to high degrees of variability. The results show the effect of temporal dimension and similarity between travel time and traffic temporal patterns, and could open the road for the improvement of the short-term forecasting methods, too

Urban Freight Transport Demand Modelling: a State of the Art

The paper provides a review of freight transport demand models for applications in urban and metropolitan areas. The perspective adopted is the short-term one of public decision-makers involved in transport planning and traffic management. The paper recalls the general methodology to be used for assessing the city logistics scenario and the features of models in relation to the planning horizons: strategic, tactical and operative. The focus is on the transport demand models able to support the assessment of short-term policies/measures. Several models and methods have been proposed. They usually refer to the multi-stage modelling approach and can be classified in terms of reference unit: truck/vehicle, commodity/quantity, delivery and mixed. The paper offers an analysis of pros and cons of each above classes of models. The research prospects are also identified