Search results for "Transportation"
showing 10 items of 860 documents
Branch-and-price-and-cut for a service network design and hub location problem
2015
In the context of combined road-rail freight transport, we study the integrated tactical planning of hub locations and the design of a frequency service network. We consider a number of real-world constraints such as multiple transshipments of requests at hubs, transport time limits for requests, request splitting, and outsourcing possibilities. To our knowledge, the combination of problem features we deal with has not been described before. We present a path-based model and solve it with a branch-and-price-and-cut algorithm. Computational experiments show that large realistic instances from a major German rail freight company can be solved close to optimality within one hour on a standard …
A GIS-Based Methodology to Estimate the Potential Demand of an Integrated Transport System
2017
In the design of a new public transport system or of an extension of an existing system, the choice of a suitable placement of stations and stops in the territory and the definition of the main axes are very important. The different choice in the number and distribution of the stops of a road transport system or of a railway transport system, in fact, makes the system more or less widespread and affects the consistency of the catchment area and the attractiveness of the system. The accessibility of a system, add to the reliability in providing the service, is the fundamental parameter influencing the modal split of the users. Therefore, the Public Administration must have tools able to eval…
The directed profitable rural postman problem with incompatibility constraints
2017
[EN] In this paper, we study a variant of the directed rural postman problem (RPP) where profits are asso- ciated with arcs to be served, and incompatibility constraints may exist between nodes and profitable arcs leaving them. If convenient, some of the incompatibilities can be removed provided that penalties are paid. The problem looks for a tour starting and ending at the depot that maximizes the difference between collected profits and total cost as sum of traveling costs and paid penalties, while satisfying remaining incompatibilities. The problem finds application in the domain of road transportation service, and in particular in the context of horizontal collaboration among carriers …
The periodic rural postman problem with irregular services on mixed graphs
2019
Abstract In this paper, we deal with an extension of the rural postman problem in which some links of a mixed graph must be traversed a given number of times over a time horizon. These links represent entities that must be serviced a specified number of times in some subsets of days (or periods) of the time horizon. The aim is to design a set of minimum-cost tours, one for each day/period of the time horizon, that satisfy the service requirements. We refer to this problem as the periodic rural postman problem with irregular services (PRPP–IS). Some practical applications of the problem can be found in road maintenance operations and road network surveillance, for example. In order to solve …
Estimating the Demand for New Destinations for a Regional Airport Based on Its Catchment Area
2020
Abstract Estimating accurately demand both at market and company level for specific goods and services can be considered a necessity for every organization. Traditional demand estimation methods may not be relevant for estimating the demand for new destinations to be introduced by a regional airport. The present paper proposes to fill this gap and to develop the demand estimation literature by presenting a novel demand estimation method. Two research objectives are developed in this regard: (1) determining the catchment area of Sibiu International Airport (a regional airport in Romania) for destinations operated by competitor airports and not by Sibiu International Airport and (2) estimatin…
Driver stress in five Spanish-speaking countries: Construct validity of the LatinSET
2020
Abstract Introduction Driver stress is a phenomenon many have studied in probably all five continents. It has been the focus of curiosity for all sorts of disciplines, and science has been unable to curb it, much less park it. Objectives This study aims to generate a unique scale that can be used in Spanish speaking countries regardless of culture or geography. Method and Materials A sample of 1954 drivers from Mexico, Guatemala, Costa Rica, Chile and Spain was comprised. Through this study, the original 21 items of the ISET (Stressful Situations in Transit Inventory, in Spanish) were used to carry out both an Exploratory Factorial Analysis as well as a Confirmatory Factorial Analysis. Resu…
Competition and cooperation for intermodal container transhipment: A network optimization approach
2018
Abstract This study presents an analysis of cross-border competition and cooperation between ports in Bangladesh and India. Nepal and Bhutan are countries without access to seaports — two landlocked countries in South Asia, depending solely on the Indian port of Kolkata for their international seaborne trade. Alternatives do exist in the Bangladeshi ports of Chittagong and Mongla but these are not exploited, in spite of trade agreements that allow access to a third country's port, and/or crossing the land of a third, intermediate, country. We formulate a mixed integer linear programming optimization model to find the optimum economic benefit of port users (serving Bhutan, Nepal and Northeas…
Investigation of the consequences of the modifiable areal unit problem in macroscopic traffic safety analysis: A case study accounting for scale and …
2019
Abstract Traffic safety analysis at the macroscopic level usually relies on previously defined areal traffic analysis zones (TAZs) that are used as the units of investigation. Hence, statistical inference is made on the basis of such units, implying that the consideration of a certain TAZ configuration may influence the results and conclusions achieved. Regarding this, the modifiable areal unit problem (MAUP) is a well-known issue in the field of spatial statistics, which refers to the effects that arise in statistical properties and estimations when there is a change in areal units of analysis. In this paper, the consequences of MAUP have been investigated through a dataset of traffic cras…
The impact of an urban toll ring on housing prices
2020
Abstract Building on standard urban economics theory we set up a stylized model within which we demonstrate that the imposition of a toll ring leads to higher housing prices within the ring, and lower outside the ring. We examine this prediction empirically by using transaction data for 15,306 dwellings in the Norwegian town of Kristiansand, where since 1992 there has been a toll ring. We find that the toll ring implies 6.9 per cent higher housing prices within the toll ring than outside it. The relationship between toll fees and housing prices seems to be stable over time. The impact of the toll ring on the prices of detached houses, apartments, row houses and twin houses is strikingly dif…
Modelling Drivers’ Adaptation to Assistance Systems
2021
Human factors research and engineering of advanced driving assistance systems (ADAS) must consider how drivers adapt to their presence. The major obstruction to this at the moment is poor understanding of the details of the adaptive processes that the human cognition undergoes when faced with such changes. This paper presents a simulation model that predicts how drivers adapt to a steering assistance system. Our approach is based on computational rationality, and demonstrates how task interleaving strategies adapt to the task environment and the driver’s goals and cognitive limitations. A supervisor controls eye movements between the driving and non-driving tasks, making this choice on the …