Search results for " technologies."
showing 10 items of 2689 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 …
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…
Flexible work arrangements and household-related journeys. Who takes the lead in dual-earner heterosexual couples?
2022
International audience; This research provides an exploration of the relationship between flexible work arrangements (FWA), CO2 emissions, and household travel allocation among dual-earner couples. Using data from the United Kingdom National Travel Survey for the period between 2002 and 2017, we develop a path analysis approach based on SEM that allows for a comprehensive study of travel behavior and trade-off effects. Results suggest that, although the partner who benefits from FWAs tends to carry out domestic provision and maintenance activities, the allocation of tasks within the household is still asymmetrical. Results also outline that the presence of children will intensely affect the…
Performance of a sustainable asphalt mix incorporating high RAP content and novel bio-derived binder
2019
The recent drive to find ways to increase sustainability and decrease costs in asphalt paving has led researchers to find innovative ways to incorporate more recycled materials and bio-derived binders into mixes with varying success. A new novel bio-derived binder made from refined pine chemistry stabilised with a polymer can increase the sustainability of asphalt mixes while maintaining pavement performance. Laboratory performance testing was conducted on asphalt mixes containing 50% Reclaimed Asphalt Pavement (RAP) by mix weight and the novel bio-derived binder. Results show that the bio-derived binder outperforms the conventional 50/70 pen grade binder mixes with respect to resistance to…
Intrinsic adhesive and cohesive assessment of the moisture sensitivity of bio-rejuvenated recycled asphalt binders
2019
Alternative binders not derived from fossil fuels, known as biobinders, are opening new paths for multiple applications in road infrastructure. Biobinders, usually produced from bio-oils obtained from the processing of biomass and industry by-products, are tuneable materials whose properties can be adjusted to meet specific targets. For this reason, an interesting approach is to couple biobinders with Reclaimed Asphalt (RA) by taking advantage of their rejuvenating properties to design bio-asphalt mixtures with high-content RA and no additional virgin bitumen. Recent research has proven the feasibility of this approach through validation at full-scale (BioRePavation project). However certai…
The Current and Future Role of Carsharing in Palermo: Analysis of Collected Data and Results of a Customer Satisfaction Survey
2018
In recent years many cities, both in Italy and abroad, have adopted Sustainable Urban Mobility Plans, in which one of the key action is the developing of the sharing mobility. The aim of the paper is to define the role that carsharing plays in Palermo today and it will play in the future, thanks to the adoption of new strategies, such as the introduction of the free-floating system, and transport demand orientation policies, such as the increase in the parking fees for private cars or the expansion of the ZTL. The average user profile of carsharing in Palermo has been identified through a customer satisfaction survey and the potential demand of carsharing in Palermo has been studied using G…
Transport engineering and reduction in crime: the Medellín case
2016
This study analyses the impact of the aerial cable car public transport system, locally known as Metrocable, in Medellín (Colombia), on the reduction in crime. As part of the municipal policies of social urbanism, Metrocable has contributed to the social integration of the population in the outlying neighbourhoods, which has increased safety in Medellín. This case is clearly of great interest from the point of view of Criminal Sciences, demonstrating how crime can be combated by using tools beyond ius puniendi. DOI: http://dx.doi.org/10.4995/CIT2016.2016.3434