A traffic analysis zone definition: a new methodology and algorithm

This paper develops a comprehensive approach to the definition of transportation analysis zones (TAZ), and therein, presents a new methodology and algorithm for the definition of TAZ embedded in geographic information systems software, improves the base algorithm with several local algorithms, and comprehensively analyses the obtained results. The results obtained are then compared to these presently used in the transportation analysis process of the Lisbon Metropolitan Area. The proposed algorithm presents a new methodology for TAZ design based on a smoothed density surface of geocoded travel demand data. The algorithm aims to minimise the loss of information when moving from a continuous representation of the origin and destination of each trip to their discrete representations through zones, and focuses on the trade-off between the statistical precision, geographical error, and the percentage of intra-zonal trips of the resulting OD matrix. The results for the Lisbon Metropolitan Area case study suggest a significant improvement in OD matrix estimates compared to current transportation analysis practises based on administrative units.

The changing role of decision support instruments in integrated infrastructure planning: lessons from the Sustainability Check

This article draws lessons about recent innovations in decision support for coping with challenges in integrated infrastructure planning strategies. After setting up a conceptual framework for the scope of analysis and the use of information in infrastructure planning, the empirical section explores the introduction of early-stage sustainability assessment tools. Data collection draws on experiences gained in the Netherlands with a new tool: ‘Sustainability Check’. We conclude that such instruments have a number of capacities that address the challenges of area-oriented planning: (a) bringing together information about the comprehensive value of alternatives, (b) facilitating the generation of alternatives, (c) addressing institutional fragmentation by learning about referential frames, and (d) adding contextual perspectives to the ‘hard’ outcomes of conventional tools. We also conclude that tools such as Sustainability Check should not be seen as a replacement for conventional decision support tools, but rather as complementary to them.     

Mesoscale high-frequency variability in the Alboran Sea and its influence on fish larvae distributions

This work analyses a multidisciplinary data set including hydrological and meteorological data, satellite images, and fish larvae abundance from a high-frequency experiment conducted along a north–south transect across the Western Alboran Sea anticyclonic gyre. Four consecutive occupations of the transect, crossing the frontal area, evidenced the high-frequency variability of hydrological structures and its influence on the latitudinal and vertical distribution of fish larvae in a period of a few days. The influence of dynamical processes on fish larvae depends on the location of the spawning as well as on the larval fish position in the water column. Wind induced upwelling and/or the southward drift of the Atlantic current transport larvae of neritic species, such as Sardina pilchardus and Engraulis encrasicolus to open sea areas. At the same time, these events bring about alterations in the latitudinal and vertical distributions of mesopelagic fish larvae. The species with a relatively surface distribution, as Ceratoscopelus maderensis, were transported and accumulated to the south of the Atlantic Jet (AJ), while those with a deeper distribution in the water column, as Maurolicus muelleri or Benthosema glaciale, would be upwelled and concentrated to the north. This study shows that it is difficult to extract conclusions about the mean or preferential distributions of fish larvae when one single/synoptic survey is considered and that time evolution of hydrological structures has to be considered in order to conclude.     

Online and in-store purchase behavior: shopping channel choice in a developing economy

Transportation - Developing economies are still in the stage of e-commerce deployment, unlike in developed countries, where online shopping is already a common purchase channel. This research aims...     

Intermodal exchange stations in the city of Madrid

The City of Madrid is putting into operation Intermodal Exchange Stations (IESs) to make connections between urban and suburban transportation modes easier for users of public transportation. The purpose of this article is to evaluate the actual effects that the implementation of IESs in the City of Madrid has on the affected stakeholders: users, public transportation operators, infrastructure managers, the government, the abutters and other citizens. We develop a methodology intended to help assess the welfare gains and losses for each stakeholder. Then we apply this methodology to the case study of the Avenida de América IES in the city of Madrid. We found that it is indeed possible to arrive at win?Cwin solutions for the funding of urban transportation infrastructure, as long as the cost-benefit ratio of the project is high enough. Commuters save travel time. Bus companies diminish their costs of operation. The abutters gain in quality of life. The private operator of the infrastructure makes a fair profit. And the government is able to promote these infrastructure facilities without spending more of its scarce budgetary resources.     

Optimal distribution of financial incentives to foster off-hour deliveries in urban areas

The main objective of this paper is to develop mathematical formulations to gain insight into the best way to distribute financial incentives to receivers of urban deliveries to maximize participation in off-hour deliveries. The paper considers two different types of incentive budgets: exogenous, and endogenous. The exogenous case represents the condition in which an external decision maker determines the incentive budget that is to be distributed among potential participants in off-hour deliveries. In the case of an endogenous incentive budget, the entity distributing the incentives must raise the necessary funds using revenue generation mechanisms such as tolls and fines. The optimal incentives are obtained from the Karush–Kuhn–Tucker conditions of a mathematical program that maximizes the number of truck trips shifted to the off-hours as a function of the incentives. The mathematical models developed in this paper provide guidelines about how to optimally distribute financial incentives to foster off-hour deliveries.     

Geometric modelling of bulbous bows with the use of non-uniform rational B-spline surfaces

Nowadays, bulbous bow forms have become a common design feature in most conventional ship designs. The design of a bulbous bow is usually attempted with the use of certain form parameters that are imposed using the designer's experience or regression values that provide the optimum parameters based on experimental tests or computational fluid dynamics (CFD) calculations. In this article, the geometric modelling of a bulbous bow form that complies with a series of parameters is presented. First, a wire model was constructed with cubic B-spline curves that hold certain form parameters that the designer wants to impose. Second, a B-spline surface that fits these splines was mathematically constructed. A review of the influence of the design parameters used on the bulbous bow properties was made. This method could be used prior to numerical optimization of a bulbous bow because different variations of the design can be easily generated. These variations can be tested numerically using CFD software. A practical application example of the method is shown.     

A Two-Stage Optimization Model for Staggered Work Hours

Traditional or standard work schedules refer to the requirement that workers must be at work the same days and during the same hours each day. This requirement constrains work-related trip arrivals, and generates morning and afternoon peak hours due to the concentration of work days and/or work hours. Alternative work schedules seek to reschedule work activities away from this traditional requirement. The aim is to flatten the peak hours by spreading the demand (i.e., assigning it to the shoulders of the peak hour), lowering the peak demand. This not only would reduce societal costs but also can help to minimize the physical requirements. In this article, a two-stage optimization model is presented to quantify the effects of staggered work hours under incentive policies. In the first stage, a variation of the generalized quadratic assignment problem is used to represent the firm’s assignment of workers to different work starting times. This is the input of a nonlinear complementarity problem that captures the behavior of the users of the transportation network who are seeking to overcome the constraints imposed by working schedules (arrival times). Two examples are provided to show how the model can be used to (a) quantify the effects and response of the firm to external incentives and (b) evaluate what type of arrangements in starting times are to be made in order to achieve a social optimum.