A cooperative waiting strategy based on elliptical areas for the Dynamic Pickup and Delivery Problem with Time Windows

The purpose of this paper to present a cooperative scheduling algorithm for solving the Dynamic Pickup and Delivery Problem with Time Windows (DPDPTW). The idea behind cooperative waiting strategies is to calculate simultaneously the waiting times for all nodes in the solution. Classical non‐cooperative scheduling algorithms perform the scheduling for each route independently of the scheduling of the other routes. We present the Cooperative Scheduling Problem (CSP) based on the elliptical areas generated by vehicles waiting at their nodes. The CSP is solved by means of a genetic algorithm and is evaluated by using a set of benchmarks based on real‐life data found in the literature. Initially, two waiting strategies are presented: Wait‐Early‐Time scheduling and Balanced‐Departure scheduling. Extensive empirical simulations have been carried out by analyzing the degree of dynamism and the average waiting time, a new concept defined to take into account the gap between the time windows of pickup and delivery nodes. Copyright © 2016 John Wiley & Sons, Ltd.     

Rail freight transport and demand requirements: an analysis of attribute cut-offs through a stated preference experiment

This paper analyses the choice between road and rail in Spain where rail market share for freight is still residual. Discrete choice models are estimated with data obtained through a two-phase fieldwork, thus allowing us to carry out a stated preference efficient design for each interviewee. We analyse the existence of attribute cut-offs and the presence of a segment of the population with a zero value of frequency. Our results show that ignoring the existence of cut-offs and segments of the population with polarised valuations can lead to erroneous conclusions in terms of the possibilities of rail for absorbing significant quota.     

Measuring the benefits derived from a transportation investment

This paper reviews the problems associated with application of the concept of consumers' surplus to the measurement of benefits derived from a transportation investment. This review is warranted since such measurement is very complicated when alternative modes or different paths are available to the users and benefit measures have been proposed which, on the surface, appear not to agree. In particular, as Mohring (1976), Williams (1976) and Agnello (1977), among others, have discussed, demand curves for interdependent modes will shift in response to a modal specific improvement, i.e. a unimodal investment, thereby complicating the measurement of consumers' surplus. The perspective taken in this paper resolves seeming inconsistencies in the literature regarding the directions of demand shifts and the correct measure to be used in calculating changes in consumer's surplus following an investment. This is accomplished by introducing an aggregate, origin-destination demand curve which is independent of the alternative modes actually available and from which traditional modal demands can be derived. An approach for deriving the modal demands from the aggregate demand and the behavioral assumptions behind the aggregate supply is described; the aggregate demand is used to unequivocably determine the directions of shifts in the modal demand curves due to specific modal investments. The resulting consistency of modal and aggregate demand is shown to lead to an unambiguous measure of total consumers' surplus variation. Extensions to include producers' surplus are also given.     

Towards a general microeconomic model for the operation of public transport

After Vickrey's view, Mohring constructed a microeconomic model to determine the optimal frequency of buses serving a corridor with fixed demand. The main result was that frequency should be proportional to the square root of demand. The role of users' costs was shown to be crucial. This approach has evolved over the past decades, improving our understanding of public transport operations. This paper describes and analyses the evolution of microeconomic models for the analysis of public transport services with parametric demand, leading towards a more comprehensive one. An in-depth review of all the contributions in the academic literature is presented, emphasizing both the treatment of variables and the form of the results mostly in terms of frequency and fleet size. A series of partial new elements is also identified. An extension of Jansson's model for a single period is developed analytically, including the effect of vehicle size on operating costs and the influence of crowding on the value of time. Numerical simulations are used for comparison and analysis. A general model is then proposed where bus operations are optimized accounting for a number of simultaneous relations. Finally, the different models are discussed and compared.     

Value of accessibility to Bogotá's bus rapid transit system

With several successful cases world‐wide, bus rapid transit (BRT) has reemerged as a cost‐effective transportation alternative for urban mobility. Despite the resurgence of BRT, there is a world‐wide paucity of research examining its ability to spur and development. By estimating spatial hedonic price functions, the paper determines the extent to which access to BRT stations in Bogotá, Colombia, currently are capitalized into land values. Results suggest that for every 5 min of additional walking time to a BRT station, the rental price of a property decreases by between 6.8 and 9.3%, after controlling for structural characteristics, neighbourhood attributes and proximity to the BRT corridor. Evaluated at the average walking time to a BRT station, this effect translates into an elasticity of between ??0.16 and ??0.22. Although these estimates cannot be attributable directly to the presence of the BRT system because a cross‐sectional design is used, they suggest that the land market in Bogotá values access to BRT station locations.     

What determines university student’s willingness to pay for bikeways?

Transportation - Inadequate infrastructure is recognized as an important barrier to cycling; therefore, improvements in the provision of bicycle facilities, such as bikeways, are frequently...     

Classifying Ports for Efficiency Benchmarking: A Review and a Frontier-based Clustering Approach

Abstract

Port efficiency and port clustering are two aspects that have received different degrees of attention in the existing literature. While the actual estimation of port efficiency has been extensively studied, the existing literature has paid little attention to developing robust methodologies for port classification. In this paper, we review the literature on classification methods for port efficiency, and present an approach that combines stochastic frontier analysis, clustering and self-organized maps (SOM). Cluster methodologies that build on the estimated cost function parameters could group ports into performance metrics’ categories. This helps when setting improvement targets for ports as a function of their specific cluster. The methodology is applied to a database of Spanish port authorities. The dendrogram features three clusters and five outlier Spanish Port Authorities. SOM are employed to track the temporal evolution of Spanish Port Authorities that are of special interest for some reasons (i.e. outliers). Results show that use of a combination of cost frontier and cluster methods to define robust port typology and SOMs, jointly or in isolation, offers useful information to the decision-makers.     

Estimation of a route choice model for urban public transport using smart card data

This paper describes a logit model of route choice for urban public transport and explains how the archived data from a smart card-based fare payment system can be used for the choice set generation and model estimation. It demonstrates the feasibility and simplicity of applying a trip-chaining method to infer passenger journeys from smart card transactions data. Not only origins and destinations of passenger journeys can be inferred but also the interchanges between the segments of a linked journey can be recognised. The attributes of the corresponding routes, such as in-vehicle travel time, transfer walking time and to get from alighting stop to trip destination, the need to change, and the time headway of the first transportation line, can be determined by the combination of smart card data with other data sources, such as a street map and timetable. The smart card data represent a large volume of revealed preference data that allows travellers' behaviour to be modelled with higher accuracy than by using traditional survey data. A multinomial route choice model is proposed and estimated by the maximum likelihood method, using urban public transport in ?ilina, the Slovak Republic, as a case study     

Implications of Thresholds in Discrete Choice Modelling

Abstract

Individual choices are affected by complex factors and the challenge consists of how to incorporate these factors in order to improve the realism of the modelling work. The presence of limits, cut‐offs or thresholds in the perception and appraisal of both attributes and alternatives is part of the complexity inherent to choice‐making behaviour. The paper considers the existence of thresholds in three contexts: inertia (habit or reluctance to change), minimum perceptible changes in attribute values, and as a mechanism for accepting or rejecting alternatives. It discusses the more relevant approaches in modelling these types of thresholds and analyses their implications in model estimation and forecasting using both synthetic and real databanks. It is clear from the analysis that if thresholds exist but are not considered, the estimated models will be biased and may produce significant errors in prediction. Fortunately, there are practical methods to attack this problem and some are demonstrated.