Search results for "Logistic"

Capacity-based calculation of passenger car equivalents using traffic simulation at double-lane roundabouts

2018

Abstract Calculation of passenger car equivalents for heavy vehicles represents the starting point for the operational analysis of road facilities and other traffic management applications. This paper introduces a criterion to find the passenger car equivalents that reflect traffic conditions at double-lane roundabouts, where the capacity is typically estimated for each entry lane. Based on the equivalence defined by the proportion of capacity used by vehicles of different classes, the criterion implies a comparison between the capacity that would occur with a traffic demand of passenger cars only and the capacity reached beginning from a demand with a certain percentage of heavy vehicles. …

Trip Characteristics Analysis of the Effects of a Travel Behavior Change Program

2018

[EN] Travel behavior change programs (TBCP) are measures or actions specifically designed to motivate people to reduce their car use. This study contributes to the literature on rigorous evaluation of the effects of participating in TBCP. In particular, we analyze the effect of TBCP in relation to a potential for a reduction in car use. In contrast to previous studies, the effect of TBCP is analyzed considering two characteristics of the trip: travel companion and time of trip. The TBCP, consisting of three persuasion actions customized to the needs of the participants in the research, was designed and implemented in Valencia (Spain). To evaluate the effects of participating in the TBCP, a …

Communal Transportation: Challenges for Largescale Routing Heuristics

2007

In this report we review the central transportation logistics problems arising in the communal sector, using information gathered from several large communes in Finland and previous literature. Most of the communal transportation problems can be modelled as different variants of the vehicle routing problem. The basic features of the problems are described, modelled and analyzed, and the relevant previous research on the topics is reviewed. In addition, some possible new solution strategies are suggested.

Development of International Freight Transit in Latvia

2013

Abstract International freight transit is transportation of goods through third countries which are neither senders or consumers of the transported freight. International freight transit provides the use of transport infrastructure capacities and the development of transport infrastructure in Latvia, especially in seaports and railways. In Latvia approximately 97% of all transported freight carried by railway is international freight transit. The turnover of Latvia's seaports is approximately 90% international freight transit transport. This paper describes comparative position of Latvia in Logistics Performance Index and assesses international competitiveness of Latvia's international frei…

Bidirectional labeling for solving vehicle routing and truck driver scheduling problems

2020

Abstract This paper studies the vehicle routing and truck driver scheduling problem where routes and schedules must comply with hours of service regulations for truck drivers. It presents a backward labeling method for generating feasible schedules and shows how the labels generated with the backward method can be combined with labels generated by a forward labeling method. The bidirectional labeling is embedded into a branch-and-price-and-cut approach and evaluated for hours of service regulations in the United States and the European Union. Computational experiments show that the resulting bidirectional branch-and-price-and-cut approach is significantly faster than unidirectional counterp…

A negotiation protocol to improve long distance truck parking

2017

Algorithms for Pallet Building and Truck Loading in an Interdepot Transportation Problem

2016

This paper deals with the problem of a logistics company that has to serve its customers by first putting the products on pallets and then loading the pallets into trucks. Besides the standard geometric constraints of products not overlapping each other and not exceeding the dimensions of pallets and trucks, in this real problem, there are many other constraints, related to the total weight of the load, the maximum weight supported by each axle, and the distribution of the load inside the truck. Although the problem can be decomposed into two phases, pallet loading and truck loading, we have taken a combined approach, building and placing pallets at the same time. For each position in the t…

A Branch-and-Cut Algorithm for the Single Truck and Trailer Routing Problem with Satellite Depots

2016

International audience; In the single truck and trailer routing problem with satellite depots (STTRPSD), a truck with a detachable trailer based at a main depot must serve the demand of a set of customers accessible only by truck. Therefore, before serving the customers, it is necessary to detach the trailer in an appropriate parking place (called either a satellite depot or a trailer point) and transfer goods between the truck and the trailer. This problem has applications in milk collection for farms that cannot be reached using large vehicles. In this work we present an integer programming formulation of the STTRPSD. This formulation is tightened with several families of valid inequaliti…

Branch-and-Price-and-Cut for the Truck-and-Trailer Routing Problem with Time Windows

2018

In this paper, we present a new branch-and-price-and-cut algorithm to solve the truck-and-trailer routing problem with time windows (TTRPTW) and two real-world extensions. In all TTRPTW variants, the fleet consists of one or more trucks that may attach a trailer. Some customers are not accessible with a truck-and-trailer combination, but can however be serviced by one if the trailer is previously detached and parked at a suitable location. In the first extension, the planning horizon comprises two days and customers may be visited either on both days or only once, in which case twice the daily supply must be collected. The second extension incorporates load transfer times depending on the …

Mathematical models for multicontainer loading problems

2017

Abstract This paper deals with the problem of a distribution company that has to serve its customers by putting first the products on pallets and then loading the pallets onto trucks. We approach the problem by developing and solving integer linear models. We start with basic models, that include the essential features of the problem, such as respecting the dimensions of the truck, and not exceeding the total weight capacity and the maximum weigh capacity on each axle. Then, we add progressively new conditions to consider the weight and volume of pallet bases and to include other desirable features for the solutions to be useful in practice, such as the position of the center of gravity and…