Coupled models for the dynamics of bridges under high-speed rail traffic

The dynamic effects of high-speed trains on viaducts are important issues for the design of the structures, as well as for determining safe running conditions of trains. In this work we start by reviewing the relevance of some basic moving load models for the dynamic action of vertical traffic loads. The study of lateral dynamics of running trains on bridges is of importance mainly for the safety of the traffic, and may be relevant for laterally compliant bridges. These studies require 3D coupled vehicle-bridge models and consideration of wheel to rail contact. We describe here a fully nonlinear coupled model, formulated in absolute coordinates and incorporated into a commercial finite element framework. An application example is presented for a vehicle subject to a strong wind gust traversing a bridge, showing the relevance of the nonlinear wheel-rail contact model as well as the interaction between bridge and vehicle.

Integration of congestion pricing and intertemporal preference rate in social welfare function

Assessing social benefits in transport policy implementation has been studied by many researchers using theoretical or empirical measures. However, few of them measure social benefit using different discount rates including the inter-temporal preferences rate of users, the private investment discount rate and the inter-temporal preferences rate of the government. In general, the social discount rate used is the same for all social actors. Therefore, this paper aims to assess a new method by integrating different types of discount rate belonging to different social actors in order to measure the real benefits of each actor in the short, medium and long term. A dynamic simulation is provided by a strategic Land-Use and Transport Interaction (LUTI) model. The method is tested by optimizing a cordon toll scheme in Madrid considering socio- economic efficiency and environmental criteria. Based on the modified social welfare function (WF), the effects on the measure of social benefits are estimated and compared with the classical WF results as well. The results of this research could be a key issue to understanding the relationship between transport system policies and social actors' benefits distribution in a metropolitan context. The results show that the use of more suitable discount rates for each social actor had an effect on the selection and definition of optimal strategy of congestion pricing. The usefulness of the measure of congestion toll declines more quickly overtime.

Modelling the relationship between urban environment and travel behaviour: policy and indicators

Due to the necessity to undertake activities, every year people increase their standards of travelling (distance and time). Urban sprawl development plays an important role in these "enlargements". Thus, governments invest money in an exhaustiva search for solutions to high levels of congestion and car-trips. The complex relationship between urban environment and travel behaviour has been studied in a number of cases. Thus, the objective of this paper is to answer the important question of which land-use attributes influence which dimensions of travel behaviour, and to verify to what extent specific urban planning measures affect the individual decision process, by exhaustiva statistical and systematic tests. This paper found that a crucial issue in the analysis of the relationship between the built environment and travel behaviour is the definition of indicators. As such, we recommend a feasible list of indicators to analyze this relationship.

Integration of congestion pricing and intertemporal preferences rate integration in social welfare function

Many researchers have used theoretical or empirical measures to assess social benefits in transport policy implementation. However, few have measured social benefits by using discount rates, including the intertemporal preference rate of users, the private investment discount rate, and the intertemporal preference rate of the government. In general, the social discount rate used is the same for all social actors. This paper aims to assess a new method by integrating different types of discount rates belonging to different social actors to measure the real benefits of each actor in the short term, medium term, and long term. A dynamic simulation is provided by a strategic land use and transport interaction model. The method was tested by optimizing a cordon toll scheme in Madrid, Spain. Socioeconomic efficiency and environmental criteria were considered. On the basis of the modified social welfare function, the effects on the measure of social benefits were estimated and compared with the classical welfare function measures. The results show that the use of more suitable discount rates for each social actor had an effect on the selection and definition of optimal strategy of congestion pricing. The usefulness of the measure of congestion toll declines more quickly over time. This result could be the key to understanding the relationship between transport system policies and the distribution of social actors? benefits in a metropolitan context.

Assessing the impact of adaptive accessibility on the optimal transport policy implementation by using an integrated land-use/transport model for Madrid

Accessibility is an essential concept widely used to evaluate the impact of land-use and transport strategies in transport and urban planning. Accessibility is typically evaluated by using a transport model or a land-use model independently or successively without a feedback loop, thus neglecting the interaction effects between the two systems and the induced competition effects among opportunities due to accessibility improvements. More than a mere methodological curiosity, failure to account for land- use/transport interactions and the competition effect may result in large underestimation of the policy effects. With the recent development of land-use and transport interaction (LUTI) models, there is a growing interest in using these models to adequately measure accessibility and evaluate its impact. The current study joins this research stream by embedding an accessibility measure in a LUTI model with two main aims. The first aim is to account for adaptive accessibility, namely the adjustment of the potential accessibility due to the effect of competition among opportunities (e.g., workplaces) as a result of improved accessibility. LUTI models are particularly suitable for assessing adaptive accessibility because the competition factor is a function of the number of jobs, which is related to land-use attractiveness and the number of workers which is related, among other factors, to the transport demand. The second aim is to identify the optimal implementation scenario of policy measures on the basis of the potential and adaptive accessibility and analyse the results in terms of social welfare and accessibility. The metropolitan area of Madrid is used as a case-study and two transport policy instruments, namely a cordon toll and bus frequency increase, have been chosen for the simulation study in order to present the usefulness of the approach to urban planners and policy makers. The MARS model (Metropolitan Activity Relocation Simulator) calibrated for Madrid was employed as the analysis tool. The impact of accessibility is embedded in the model through a social welfare function that includes not only costs and benefits to both road users and transport operators, but also costs and benefits for the government and society in general (external costs). An optimisation procedure is performed by the MARS model for maximizing the value of objective function in order to find the best (optimal) policy imp lementations intensity (i.e., price, frequency). Last, the two policy strategies are evaluated in terms of their accessibility. Results show that the accessibility with competition factor influences the optimal policy implementation level and also generates different results in terms of social welfare. In addition, mapping the difference between the potential and the adaptive accessibility indicators shows that the main changes occur in areas where there is a strong competition among land-use opportunities.

An Integrated Transport Planning Framework Involving a Combined Utility-Regret Approach

Sustainable transport planning requires an integrated approach involving strategic planning, impact analysis and multi-criteria evaluation. This study aims at relaxing the utility-based decision-making assumption by newly embedding anticipated-regret and combined utility-regret decision mechanisms in an integrated transport planning framework. The framework consists of a two-round Delphi survey, an integrated land-use and transport model for Madrid, and multi-criteria analysis. Results show that (i) regret-based ranking has similar mean but larger variance than utility-based ranking; (ii) the least-regret scenario forms a compromise between the desired and the expected scenarios; (iii) the least-regret scenario can lead to higher user benefits in the short-term and lower user benefits in the long-term; (iv) utility-based, regret-based and combined utility-regret-based multi-criteria analysis result in different rankings of policy packages; and (v) the combined utility-regret ranking is more informative compared with utility-based or regret-based ranking.

Relation of Lagragian structures and drifter dynamics in the Gulf of Mexico

We use a Lagrangian descriptor (the so called function M) which measures the length of particle trajectories on the ocean surface over a given interval of time. With this tool we identify the Lagrangian skeleton of the flow and compare it on three datasets over the Gulf of Mexico during the year 2010. The satellite altimetry data used come from AVISO and simulations from HYCOM GOMl0.04 experiments 30.1 and 31.0. We contrast the Lagrangian structure and transport using the evolution of several surface drifters. We show that the agreement in relevant cases between Lagrangian structures and dynamics of drifters depends on the quality of the data on the studied area.

Using floating car data to analyse the effects of ITS measures and eco-driving

The road transportation sector is responsible for around 25% of total man-made CO2 emissions worldwide. Considerable efforts are therefore underway to reduce these emissions using several approaches, including improved vehicle technologies, traffic management and changing driving behaviour. Detailed traffic and emissions models are used extensively to assess the potential effects of these measures. However, if the input and calibration data are not sufficiently detailed there is an inherent risk that the results may be inaccurate. This article presents the use of Floating Car Data to derive useful speed and acceleration values in the process of traffic model calibration as a means of ensuring more accurate results when simulating the effects of particular measures. The data acquired includes instantaneous GPS coordinates to track and select the itineraries, and speed and engine performance extracted directly from the on-board diagnostics system. Once the data is processed, the variations in several calibration parameters can be analyzed by comparing the base case model with the measure application scenarios. Depending on the measure, the results show changes of up to 6.4% in maximum speed values, and reductions of nearly 15% in acceleration and braking levels, especially when eco-driving is applied.

The Transport Debate. Book Description

The lucid and accessible analysis of the key policy issues of transport is more than welcomed, now when the link between social and economic efficiency and transport is more than proved. The authors, two experts in the field, Shaw and Docherty give concise information on a timeliness topic showing that decision-making in transport (i.e. privatization of transport networks and services) has long term negative effects on the mobility of people and their accessibility to their key life activities.

Development of the infrastructure for a multi-agent traffic management system simulation

This document contains detailed description of the design and the implementation of a multi-agent application controlling traffic lights in a city together with a system for simulating traffic and testing. The goal of this thesis is to design and build a simplified intelligent and distributed solution to the problem with the traffic in the big cities following different good practices in order to allow future refining of the model of the real world. The problem of the traffic in the big cities is still a problem that cannot be solved. Not only is the increasing number of cars a reason for the traffic jams, but also the way the traffic is organized. Usually, the intersections with traffic lights are replaced by roundabouts or interchanges to increase the number of cars that can cross the intersection in certain time. But still there are places where the infrastructure cannot be changed and the traffic light semaphores are the only way to control the car flows. In real life, the traffic lights have a predefined plan for change or they receive information from a centralized system when and how they have to change. But what if the traffic lights can cooperate and decide on their own when and how to change? Using this problem, the purpose of the thesis is to explore different agent-based software engineering approaches to design and build a non-conventional distributed system. From the software engineering point of view, the goal of the thesis is to apply the knowledge and use the skills, acquired during the various courses of the master program in Software Engineering, while solving a practical and complex problem such as the traffic in the cities.

Modeling GHG emissions, N and C dynamics in Spanish agricultural soils.

To date, only few initiatives have been carried out in Spain in order to use mathematical models (e.g. DNDC, DayCent, FASSET y SIMSNIC) to estimate nitrogen (N) and carbon (C) dynamics as well as greenhouse gases (GHG) in Spanish agrosystems. Modeling at this level may allow to gain insight on both the complex relationships between biological and physicochemical processes, controlling the processes leading to GHG production and consumption in soils (e.g. nitrification, denitrification, decomposing, etc.), and the interactions between C and N cycles within the different components of the continuum plant-soil-environment. Additionally, these models can simulate the processes behind production, consumition and transport of GHG (e.g. nitrous oxide, N2O, and carbon dioxide, CO2) in the short and medium term and at different scales. Other sources of potential pollution from soils can be identified and quantified using these process-based models (e.g. NO3 y NH3).

Urban transport interchanges: Importance-Performance analysis for evaluating perceived quality

As the world becomes more urbanised, public transport in cities must seek to provide viable alternatives to individual car transport. At an urban level, interchanges in public transport networks provide easy transfers between and within different transport modes and facilitate seamless travel. This study proposes a methodological framework with which to identify the factors that travellers view as key elements of an urban transport interchange. An attitudinal survey was undertaken in order to collect information about users? needs and perceptions in the Moncloa interchange in Madrid, Spain. The results obtained from an Importance-Performance Analysis (IPA) show that aspects related to the signposting of different facilities and transport services, the internal design of the interchange and the surrounding area, and safety and security are the greatest strengths of the interchange.

La Península Ibérica en el transporte masivo de mercancías entre Europa y África : futuras autopistas del mar

La competitividad del transporte de mercancías depende del estado y funcionamiento de las redes existentes y de sus infraestructuras, no del modo de transporte. En concreto, la rentabilidad o la reducción de los costes de producción del transporte marítimo se vería incrementado con el uso de buques de mayor capacidad y con el desarrollo de plataformas portuarias de distribución o puertos secos, ya que el 90% del comercio entre la Unión Europea y terceros países se realiza a través de sus puertos a un promedio de 3,2 billones de toneladas de mercancías manipuladas cada año y el 40% del tráfico intraeuropeo utiliza el transporte marítimo de corta distancia. A pesar de que los puertos europeos acogen anualmente a más de 400 millones de pasajeros, los grandes desarrollos se han producido en los puertos del norte de Europa (Róterdam, Amberes, Ámsterdam). Los países del Sur de Europa deben buscar nuevas fórmulas para ser más competitivos, ya sea mediante creación de nuevas infraestructuras o mediante refuerzo de las existentes, ofreciendo los costes de los puertos del Norte. El fomento del transporte marítimo y fluvial como alternativa al transporte por carretera, especialmente el transporte marítimo de corta distancia, ha sido impulsado por la Comisión Europea (CE) desde 2003 a través de programas de apoyo comunitario de aplicación directa a las Autopistas del Mar, a modo de ejemplo, cabría citar los programas Marco Polo I y II, los cuales contaron con una dotación presupuestaria total de 855 millones de euros para el período 2003 – 2013; en ese período de tiempo se establecieron objetivos de reducción de congestión vial y mejora del comportamiento medio ambiental del sistema de transporte de mercancías dentro de la comunidad y la potenciación de la intermodalidad. El concepto de Autopista del Mar surge en el Libro Blanco de Transportes de la Comisión Europea “La política europea de transportes de cara al 2010: La hora de la verdad” del 12 de diciembre de 2001, en el marco de una política europea para fomento y desarrollo de sistemas de transportes sostenibles. Las Autopistas del Mar consisten en rutas marítimas de corta distancia entre dos puntos, de menor distancia que por vía terrestre, en las que a través del transporte intermodal mejoran significativamente los tiempos y costes de la cadena logística, contribuyen a la reducción de accidentes, ruidos y emisiones de CO2 a la atmósfera, permite que los conductores pierdan horas de trabajo al volante y evita el deterioro de las infraestructuras terrestres, con el consiguiente ahorro en mantenimiento. La viabilidad de una Autopista del Mar depende tanto de factores de ubicación geográficos, como de características propias del puerto, pasando por los diferentes requerimientos del mercado en cada momento (energéticos, medio ambientales y tecnológicos). Existe un elemento nuevo creado por la Comisión Europea: la red transeuropea de transportes (RTE-T). En el caso de España, con sus dos accesos por los Pirineos (La Junquera e Irún) como únicos pasos terrestres de comunicación con el continente y con importantes limitaciones ferroviarias debido a los tres anchos de vía distintos, le resta competitividad frente al conjunto europeo; por el contrario, España es el país europeo con más kilómetros de costa (con más de 8.000 km) y con un emplazamiento geográfico estratégico, lo que le convierte en una plataforma logística para todo el sur de Europa, por lo que las Autopistas del Mar tendrán un papel importante y casi obligado para el desarrollo de los grandes corredores marítimos que promueve Europa. De hecho, Gijón y Vigo lo han hecho muy bien con sus respectivas líneas definidas como Autopistas del Mar y que conectan con el puerto francés de Nantes-Saint Nazaire, ya que desde ahí los camiones pueden coger rutas hacia el Norte. Paralelamente, la Unión Europea ha iniciado los pasos para el impulso de la primera Autopista del Mar que conectará España con el mercado de Reino Unido, concretamente los Puertos de Bilbao y Tilbury. Además, España e Italia sellaron un acuerdo internacional para desarrollar Autopistas del Mar entre ambos países, comprometiéndose a impulsar una docena de rutas entre puertos del litoral mediterráneo español y el italiano. Actualmente, están en funcionando los trayectos como Barcelona-Génova, Valencia-Civitavecchia y Alicante- Nápoles, notablemente más cortos por mar que por carretera. Bruselas identificó cuatro grandes corredores marítimos que podrían concentrar una alta densidad de tráfico de buques, y en dos de ellos España ya tenía desde un principio un papel crucial. La Comisión diseñó el 14 de abril de 2004, a través del proyecto West-Mos, una red de tráfico marítimo que tiene como vías fundamentales la denominada Autopista del Báltico (que enlaza Europa central y occidental con los países bálticos), la Autopista de Europa suroriental (que une el Adriático con el Jónico y el Mediterráneo más oriental) y también la Autopista de Europa occidental y la Autopista de Europa suroccidental (que enlazan España con Reino Unido y la Francia atlántica y con la Francia mediterránea e Italia, respectivamente). Para poder establecer Autopistas del Mar entre la Península Ibérica y el Norte de Europa primará especialmente la retirada de camiones en la frontera pirenaica, donde el tráfico pesado tiene actualmente una intensidad media diaria de 8.000 unidades, actuando sobre los puntos de mayor congestión, como por ejemplo los Alpes, los Pirineos, el Canal de la Mancha, las carreteras fronterizas de Francia y Euskadi, y proponiendo el traslado de las mercancías en barcos o en trenes. Por su parte, para contar con los subsidios y apoyos europeos las rutas seleccionadas como Autopistas del Mar deben mantener una serie de criterios de calidad relacionados con la frecuencia, coste “plataforma logística a plataforma logística”, simplicidad en procedimientos administrativos y participación de varios países, entre otros. Los estudios consideran inicialmente viables los tramos marítimos superiores a 450 millas, con un volumen de unas 15.000 plataformas al año y que dispongan de eficientes comunicaciones desde el puerto a las redes transeuropeas de autopistas y ferrocarril. Otro objetivo de las Autopistas del Mar es desarrollar las capacidades portuarias de forma que se puedan conectar mejor las regiones periféricas a escala del continente europeo. En lo que a Puertos se refiere, las terminales en los muelles deben contar con una línea de atraque de 250 m., un calado superior a 8 m., una rampa “ro-ro” de doble calzada, grúas portainer, y garantizar operatividad para un mínimo de dos frecuencias de carga semanales. El 28 de marzo de 2011 se publicó el segundo Libro Blanco sobre el futuro del transporte en Europa “Hoja de ruta hacia un espacio único europeo de transporte: por una política de transportes competitiva y sostenible”, donde se definió el marco general de las acciones a emprender en los próximos diez años en el ámbito de las infraestructuras de transporte, la legislación del mercado interior, la reducción de la dependencia del carbono, la tecnología para la gestión del tráfico y los vehículos limpios, así como la estandarización de los distintos mercados. Entre los principales desafíos se encuentran la eliminación de los cuellos de botella y obstáculos diversos de nuestra red europea de transporte, minimizar la dependencia del petróleo, reducir las emisiones de GEI en un 60% para 2050 con respecto a los niveles de 1990 y la inversión en nuevas tecnologías e infraestructuras que reduzcan estas emisiones de transporte en la UE. La conexión entre la UE y el norte de África provoca elevados niveles de congestión en los puntos más críticos del trayecto: frontera hispano-francesa, corredor del Mediterráneo y el paso del estrecho. A esto se le añade el hecho de que el sector del transporte por carretera está sujeto a una creciente competencia de mercado motivada por la eliminación de las barreras europeas, mayores exigencias de los cargadores, mayores restricciones a los conductores y aumento del precio del gasóleo. Por otro lado, el mercado potencial de pasajeros tiene una clara diferenciación en tipos de flujos: los flujos en el período extraordinario de la Operación Paso del Estrecho (OPE), enfocado principalmente a marroquíes que vuelven a su país de vacaciones; y los flujos en el período ordinario, enfocado a la movilidad global de la población. Por tanto, lo que se pretende conseguir con este estudio es analizar la situación actual del tráfico de mercancías y pasajeros con origen o destino la península ibérica y sus causas, así como la investigación de las ventajas de la creación de una conexión marítima (Autopista del Mar) con el Norte de África, basándose en los condicionantes técnicos, administrativos, económicos, políticos, sociales y medio ambientales. The competitiveness of freight transport depends on the condition and operation of existing networks and infrastructure, not the mode of transport. In particular, profitability could be increased or production costs of maritime transport could be reduced by using vessels with greater capacity and developing port distribution platforms or dry ports, seeing as 90% of trade between the European Union and third countries happens through its ports. On average 3,2 billion tonnes of freight are handled annualy and 40% of intra-European traffic uses Short Sea Shipping. In spite of European ports annually hosting more than 400 million passengers, there have been major developments in the northern European ports (Rotterdam, Antwerp, Amsterdam). Southern European countries need to find new ways to be more competitive, either by building new infrastructure or by strengthening existing infrastructure, offering costs northern ports. The use of maritime and river transport as an alternative to road transport, especially Short Sea Shipping, has been driven by the European Commission (EC) from 2003 through community support programs for the Motorways of the Sea. These programs include, for example, the Marco Polo I and II programs, which had a total budget of 855 million euros for the period 2003-2013. During this time objectives were set for reducing road congestion, improving the environmental performance of the freight transport system within the community and enhancing intermodal transport. The “Motorway of the Sea” concept arises in the European Commission’s Transport White Paper "European transport policy for 2010: time to decide" on 12 December 2001, as part of a European policy for the development and promotion of sustainable transport systems. A Motorway of the Sea is defined as a short sea route between two points, covering less distance than by road, which provides a significant improvement in intermodal transport times and to the cost supply chain. It contributes to reducing accidents, noise and CO2 emissions, allows drivers to shorten their driving time and prevents the deterioration of land infrastructure thereby saving on maintenance costs. The viability of a Motorway of the Sea depends as much on geographical location factors as on characteristics of the port, taking into account the different market requirements at all times (energy, environmental and technological). There is a new element created by the European Commission: the trans-European transport network (TEN-T). In the case of Spain, with its two access points in the Pyrenees (La Junquera and Irun) as the only land crossings connected to the mainland and major railway limitations due to the three different gauges, it appears less competitive compared to Europe as a whole. However, Spain is the European country with the most kilometers of coastline (over 8,000 km) and a strategic geographical location, which makes it a logistics platform for the all of Southern Europe. This is why the Motorways of the Sea will have an important role, and an almost necessary one to develop major maritime corridors that Europe supports. In fact, Gijon and Vigo have done very well with their respective sea lanes defined as Motorways of the Sea and which connect with the French port of Nantes-Saint Nazaire, as from there trucks can use nort-heading routes. In parallel, the European Union has taken the first steps to boost the first Motorway of the Sea linking Spain to the UK market, specifically the ports of Bilbao and Tilbury. Furthermore, Spain and Italy sealed an international agreement to develop Motorways of the Sea between both countries, pledging to develop a dozen routes between ports on the Spanish and Italian Mediterranean coasts. Currently, there are sea lanes already in use such as Barcelona-Genova, Valencia-Civitavecchia and Alicante-Naples, these are significantly shorter routes by sea than by road. Brussels identified four major maritime corridors that could hold heavy concentrate shipping traffic, and Spain had a crucial role in two of these from the beginning. On 14 April 2004 the Commission planned through the West-Mos project, a network of maritime traffic which includes the essential sea passages the so-called Baltic Motorway (linking Central and Western Europe with the Baltic countries), the southeast Europe Motorway (linking the Adriatic to the Ionian and eastern Mediterranean Sea), the Western Europe Motorway and southwestern Europe Motorway (that links Spain with Britain and the Atlantic coast of France and with the French Mediterranean coast and Italy, respectively). In order to establish Motorways of the Sea between the Iberian Peninsula and Northern Europe especially, it is necessary to remove trucks from the Pyrenean border, where sees heavy traffic (on average 8000 trucks per day) and addressing the points of greatest congestion, such as the Alps, the Pyrenees, the English Channel, the border roads of France and Euskadi, and proposing the transfer of freight on ships or trains. For its part, in order to receive subsidies and support from the European Commission, the routes selected as Motorways of the Sea should maintain a series of quality criteria related to frequency, costs "from logistics platform to logistics platform," simplicity in administrative procedures and participation of several countries, among others. To begin with, studies consider viable a maritime stretch of at least 450 miles with a volume of about 15,000 platforms per year and that have efficient connections from port to trans-European motorways and rail networks. Another objective of the Motorways of the Sea is to develop port capacity so that they can better connect peripheral regions across the European continent. Referring ports, the terminals at the docks must have a berthing line of 250 m., a draft greater than 8 m, a dual carriageway "ro-ro" ramp, portainer cranes, and ensure operability for a minimum of two loads per week. On 28 March 2011 the second White Paper about the future of transport in Europe "Roadmap to a Single European Transport Area – Towards a competitive and resource efficient transport system" was published. In this Paper the general framework of actions to be undertaken in the next ten years in the field of transport infrastructure was defined, including internal market legislation, reduction of carbon dependency, traffic management technology and clean vehicles, as well as the standardization of different markets. The main challenges are how to eliminate bottlenecks and various obstacles in our European transport network, minimize dependence on oil, reduce GHG emissions by 60% by 2050 compared to 1990 levels and encourage investment in new technologies and infrastructure that reduce EU transport emissions. The connection between the EU and North Africa causes high levels of congestion on the most critical points of the journey: the Spanish-French border, the Mediterranean corridor and Gibraltar Strait. In addition to this, the road transport sector is subject to increased market competition motivated by the elimination of European barriers, greater demands of shippers, greater restrictions on drivers and an increase in the price of diesel. On the other hand, the potential passenger market has a clear differentiation in type of flows: flows in the special period of the Crossing the Straits Operation (CSO), mainly focused on Moroccans who return home on vacation; and flows in the regular session, focused on the global mobile population. Therefore, what I want to achieve with this study is present an analysis of the current situation of freight and passengers to or from the Iberian Peninsula and their causes, as well as present research on the advantages of creating a maritime connection (Motorways of the Sea) with North Africa, based on the technical, administrative, economic, political, social and environmental conditions.

El recorrido: evaluación de las cualidades sensoriales y formales del medio urbano como parte de los criterios de caminabilidad. La ciudad de Taipei como caso de estudio

La presente investigación aborda el análisis de las cualidades del entorno urbano que inciden en la experiencia perceptiva de su recorrido. Los intereses que la motivan tienen que ver con la recuperación de la ciudad para el viandante y se sitúa dentro de un marco de intereses más amplio como es el de la ciudad sostenible. En primer lugar, se contextualiza el tema de la experiencia del recorrido a través de disciplinas diferentes como son el cine, la literatura, la arquitectura, el urbanismo, la arquitectura del paisaje, la psicología y la estética ambiental. De este modo, se refuerza el argumento en torno al papel que desempeñan la forma y otros estímulos sensoriales en la experiencia del espacio, ya sea éste urbano, arquitectónico o natural. La experiencia que las personas viven al desplazarse por un entorno viene definida por infinitos factores que van desde la configuración física del entorno recorrido, hasta el aprendizaje cultural de la persona que camina; desde los estímulos sensoriales que se reciben, hasta las condiciones físicas que posibilitan la funcionalidad del recorrido; desde las sutilezas de índole secuencial que se desvelan a medida que avanzamos, hasta las condiciones higrotérmicas en el momento en que se lleva a cabo el desplazamiento. Sin embargo, factores como las motivaciones y atenciones personales del que anda, así como sus recuerdos de experiencias anteriores, deseos, imaginación y estado de ánimo, también definen nuestra experiencia al caminar que, indudablemente, se encuentra ligada a nuestra personalidad y, por lo tanto, no puede ser exacta a la de otra persona. Conscientes de que todos estos factores se funden en un fenómeno global, y que no se dan en la vida por separado, nos hemos esforzado por independizar las cualidades sensoriales y formales, únicamente a efectos de investigación. La importancia del tema a investigar reside en las conexiones que existen entre las cualidades del medio construido y la experiencia cotidiana de su recorrido, en la medida en que dicha vinculación establece relaciones con la calidad de vida, la salud de los ciudadanos y sus sentimientos de identidad. En este sentido, el problema clave encontrado es que si la definición de la experiencia del recorrido urbano es demasiado amplia, se vuelve nebulosa e inoperativa, pero si se precisa demasiado, se pueden excluir variables importantes. Hemos concentrado nuestros esfuerzos en buscar un medio que permita hacer operativo el estudio de aspectos que, por su propia naturaleza, son difíciles de controlar y aplicar en la práctica. En este sentido, el campo de estudio que aúna interés en el tema, producción científica y vocación práctica, es el de la caminabilidad de las ciudades. Por esta razón, hemos situado nuestro trabajo dentro del marco de criterios que este campo establece para valorar un entorno caminable. Sin embargo, hemos detectado que los trabajos sobre caminabilidad tienden a desarrollarse dentro de la disciplina del planeamiento de transporte y, con frecuencia, siguiendo las mismas pautas que la investigación sobre el transporte motorizado. Además, la tendencia a proporcionar datos numéricos producto de la medición controlada de variables, para respaldar iniciativas dentro de los ámbitos de toma de decisiones, lleva consigo un progresivo alejamiento de los aspectos más sutiles y próximos de la experiencia de las personas y la especificidad de los lugares. Por estas razones, hemos estimado necesario profundizar en la experiencia peatonal explorando otras líneas de trabajo como son la habitabilidad de las ciudades, políticas llevadas a cabo para mejorar la calidad del espacio público o las certificaciones de sostenibilidad en el ámbito del urbanismo. También se han estudiado las aproximaciones gráficas a la representación y simulación de recorridos urbanos por su importancia en la comunicación y promoción de caminar. Para detectar las problemáticas implicadas en la definición de una herramienta que permita valorar, de manera operativa, la calidad de la experiencia del recorrido urbano, la metodología de valoración propuesta se ha basado en la combinación de distintos métodos y en la conjugación de tres aproximaciones: valoración por parte del investigador en calidad de experto, valoración realizada por el investigador en el papel de usuario y valoración por el ciudadano. El desarrollo de esta investigación se ha visto condicionado por la intención de aplicar lo estudiado en un caso práctico. El marco de criterios que los trabajos sobre caminabilidad de las ciudades establecen para que se dé un entorno caminable, se puede resumir en que concurran los siguientes factores: mezcla de usos, densidad de población y edificación relativamente altas, destinos públicos accesibles a pie, un alto grado de seguridad con respecto al tráfico y actos delictivos, alta funcionalidad (dimensiones, pendientes, etc.) y atractivo. Una vez definido el modelo de ciudad en que es pertinente realizar una investigación sobre las cualidades del entorno urbano responsables de que éste se perciba como atractivo, se escogió la ciudad de Taipei, entre otras razones, por cumplir con los requisitos restantes. Con respecto al caso práctico, el objetivo es detectar fortalezas y debilidades del área central de la ciudad de Taipei en cuanto a la experiencia perceptiva que proporciona a los viandantes. ABSTRACT This research addresses the analysis of the qualities of the urban environment that affect the perceptual experience of walking. The interests lying behind it are related to the recovery of the city for pedestrians, and is framed within the sustainable city framework of interests. Firstly, the issue of the experience of walking is contextualized through different disciplines such as film, literature, architecture, urban planning, landscape architecture, environmental psychology and aesthetics. This way, the argument about the role that form and other sensory stimuli play in the experience of space, whether it is urban, architectural or natural, is strengthened. The walking experience of people is defined by factors ranging from the physical configuration of the environment to the cultural background of the person who walks, from the sensory stimuli that are perceived to the physical conditions that enable the functionality of the walk, from the subtleties of sequential nature that are revealed as we move around to hygrothermal conditions at the specific time of walking. Nevertheless, factors such as personal motivations and attentions of the walker, as well as memories of past experiences, desires, imagination and mood, also define our walking experience that is undoubtedly linked to our personality and, therefore, it cannot be exactly the same as other people's experience. Being aware that all these factors come together in a total phenomenon and that, in real life, they do not exist separately, we focused on separating sensory and formal qualities only for research purposes. The importance of the research topic lies in the connections between the qualities of the built environment and the quotidian experience of walking through it, to the extent that such link establishes relationships with the quality of life, health and feelings of identity of citizens. In this sense, the key problem encountered is that, if the definition of urban walking experience is too broad, it becomes nebulous and non‐operational, but if it is too precise, important variables can be excluded. We concentrated our efforts on finding a way to operationalize the study of questions that, by their very nature, are difficult to control and apply in practice. In this regard, the field of study that combines interest in the topic, scientific production and practical purpose, is the walkability of cities. For this reason, we placed our work within the framework of the set of criteria that this field establishes for assessing an environment as walkable. However, we found that works on walkability tend to be developed within the discipline of transportation planning and often following the same guidelines that research on motorized transport. Furthermore, the tendency to provide numerical data as a result of the controlled measurement of variables in order to support initiatives in decision making areas, involves a progressive distancing from the proximity and the most subtle aspects of the experience of people, and from the specificity of places. For these reasons, we considered it was necessary to deepen into the study of pedestrians experience, by exploring other lines of work such as the livability of cities, implemented policies to improve the quality of the public space or sustainability certifications in urbanism. Graphic representation and simulation of urban walks are also studied due to their important role in communication and promotion of walking. In order to find the issues involved in defining a tool to assess, in an operational way, the quality of urban walking experience, the proposed assessment methodology is based on the combination of different methods and the synthesis of three approaches: assessment by the researcher as expert, assessment by the researcher playing the role of user and assessment by the citizens. The development of this research has been conditioned by our intention of applying it in a case study. The framework of criteria that works on walkability of cities set to define a walkable environment, can be summarized in the following factors: mix of uses, population and building density rather high, public destinations accessible on foot, high levels of safety in terms of traffic and crime, high functionality (dimensions, slopes, etc.) and attractiveness. After defining the model of city in which it is relevant to conduct an investigation on the qualities that are responsible of the attractiveness of the environment; Taipei City was selected because it meets the remaining requirements, among other reasons. Regarding the case study, the goal is to identify strengths and weaknesses in the central area of Taipei City in terms of the perceptual experience of pedestrians.