1,709 research outputs found

    Do more trucks lead to more motor vehicle fatalities in European roads? Evaluating the impact of specific safety strategies.

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    Truck operations have recently become an important focus of academic research not only because road freight transport is a key part of logistics, but because trucks are usually associated with negative externalities including pollution, congestion and traffic accidents. While the negative environmental impacts of truck activities have been extensively analyzed, comparatively little attention has been paid to the role of trucks in road accidents. A review of the literature identifies various truck-traffic safety related issues: frequency of accidents and their determinants; risk factors associated with truck driver behavior (including cell phone use, fatigue, alcohol and drugs consumption); truck characteristics and facilities (roadway types, specific lanes and electronic stability programs) to improve performance of vehiclemaneuvering; and the safety characteristics of heavy and large trucks. However, to date, there seems to have been developed few studies evaluating the complex coexistence of trucks and cars on roads and that may support the implementation of differential road safety strategies applied to them. This paper focuses on the impact on the traffic fatalities rate of the interaction between trucks and cars on roads. We also assess the efficiency of two stricter road safety regulations for trucks, as yet not harmonized in the European Union; namely, speed limits and maximum blood alcohol concentration rates. For this, econometric models have been developed from a panel data set for European Union during the years 1999–2010. Our findings show that rising motorization rates for trucks lead to higher traffic fatalities, while rising motorization rates for cars do not. These effects remain constant across Europe, even in the most highly developed countries boasting the best highway networks. Furthermore, we also find that lower maximum speed limits for trucks are effective and maximum blood alcohol concentration rates for professional drivers are only effective when they are strictly set to zero. Therefore, our results point to that the differential treatment of trucks is not only adequate for mitigating an important source of congestion and pollution, but that the implementation of stricter road safety measures in European countries for the case of trucks also contributes significantly to reducing fatalities. In summary, and as a counterpoint to the negative impact of trucks on road traffic accidents, we conclude the effectiveness of efforts made in road safety policy (based on specific traffic regulations by vehicle type imposed by member States) to counteract the safety externalities of freight transportation in the European Union. In certain sense, our study might provide indirect support to public policies implemented at the macro European level to promote multimodal transport corridors. In this respect, there is an increasing focus at the European level on how freight transport can be moved from trucks on roads to more environmentally-sustainable modes, such as rail and ship.Dirección General de Tráfico SPIP2014127

    The europeanization of the common road safety policy: an econometric analysis

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    The 2001 White Paper and its development in the 3rd European Road Safety Action Program, represent a turning point in the history of the European Road Safety Policy. The possible determinants of the road mortality in the EU over (2000-2009) are examined using a panel data. Our main finding is the negative effect and statistical significance of the Europeanization variable (the number of years that a country has been in the EU). By this variable, we test the effectiveness of EU programs to save lives in road accidents according to the years that each country has been in the EU

    The relationship between public and private bicycle use: the case of Seville

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    Despite the success achieved by Public Bicycle Sharing Systems (PBSS) across the world, several researchers provide evidence on their limitations and constraints in a medium-long term, and bicycle ownership may be considered as a complementary tool to promote a 'bicycle-culture'. This paper aims to cover the gap about the interaction between both systems (public bicycle / private bicycle) and which are the key aspects to explain the bicycle-buying decision. After a fieldwork based on surveys conducted in Seville (Spain), one of the cities currently acknowledged worldwide for its successful policy of promoting cycling, we apply a Discrete Choice Model. Our findings show that among the socio-demographic factors that favor the move from the PBSS to the private bicycle are: having a higher level of education, being more progressive ideologically-speaking, and being a resident of the city itself; while age and gender do not appear to be conclusive. Experienced users, for whom the bicycle is a part of his /her healthy lifestyle, state a greater willingness to buy a bicycle. And the main obstacles to make the jump from the PBSS to the private bicycle, and that any action plan to support private bicycle usage should take into account, are: the lack of proper parking at the origin/destination, and fear of theft

    Measuring the LCC effect on charter airlines in the Spanish airport system

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    Using a robust transfer function model methodology, the present paper seeks to offer empirical evidence regarding the size and type of effects that low-cost carriers (LCCs) have had on traffic for charter carriers (CCs) in the Spanish airport system by geographic market. We show an unmistakable substitution relationship between CCs and LCCs in the latter’s typical niche markets, national and European flights, while there is no reaction from the CCs in the segment of international flights outside the EU. Furthermore, substitution effects are smaller between CCs and LCCs on the domestic level than effects between LCCs and network carriers (NCs) and slightly larger on the European level. Lastly, CC traffic’s different sensitivity to terrorist attacks, day of the week, air accidents and the economic crisis is also evident. CCs should therefore be considered an independent category that warrants individualized analyses

    Estudio de algunas variables que afectan la comprensión de textos de física

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    The problem about the comprehension of Physics Texts by students of the First Courses at University is the axis of analysis in this paper. Our intention is to know the learning strategies that our university students use to comprehend a scientific text. We studied the cognitive activities of the students when reading the text and the relationship between them through a global coefficient of comprehension. The results obtained let us assert that it is convenient to teach adequate strategies for the comprehension of physics texts

    Evaluación de una experiencia de aula con un diseño basado en la teoría de la elaboración

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    This work proposes a model of a curricular design in Physics and its application in the classroom. It is developed according to the guidelines of the elaboration theory and it is put into practice in a basic university course. It includes an analysis of the structure of knowledge and an organization of the contents involved at different levels. Besides, it provides information about what and how to teach and what and how to evaluate. The results achieved in the classroom according to what is prescribed in this design about Waves and Sound are analyzed and discussed in this paper

    The Speed Limits Debate: Is Effective A Temporary Change? The Case Of Spain.

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    Nowadays, speeding is one of the most relevant problems for traffic safety and most resistant to change in motorized countries. The key instruments in Speed Management Policy are speed limits. This road safety strategy is often established or changed, in order to save fuel during periods of rising prices. However, the relationship between speed limits and traffic accidents, is a topic widely discussed by researchers, and there seems to be some consensus about 'speed kills.' By applying advanced time series models of unobserved components, our study investigates the impact of a temporary reduction of maximum speed limits, implemented in Spain in 2011, in terms of fuel consumption and fatalities. Our analysis shows that this measure caused a positive effect, although with a limited statistical significance, on fuel consumption and a discrete reduction in road mortality. The costs associated with this temporary change seem to explain the discrepancies between these estimates and the forecasts that initially held the Spanish government

    To take or not to take the laptop or tablet to classes, that is the question

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    In recent decades, so-called mobile learning or m-learning has become a new paradigm in education as a consequence of technological advances and the widespread use of mobile devices to access information and for communication. In this context, this paper analyzes different profiles depending on students’ preferences for taking mobile devices (specifically tablets and/or laptops) to economics classes at the University of Seville (Spain). A survey-based field study of a sample of 412 students and the application of bivariate probit models show a low level of mobile device integration in teaching (devices taken to class by only 29.8% of respondents) with a slight predominance of laptops. The results also show differences between users of the two types of devices. Students who take their laptops to class usually live at home with their family, have already used them in pre-university levels, and are concerned about recharging their devices in class. However, although users who take their tablets to class also live with their parents, they are much more active on social network sites and more concerned about the quality of the internet connection. These findings enable the design of strategies to encourage students to attend class with their own mobile devices

    A Novel Hybrid Approach to Improve Performance on Frequency Division Duplex Systems with Linear Precoding

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    The final publication is available http://dx.doi.org/DOI: 10.1007/978-3-642-13803-4_31[Abstrtact] Linear precoding is an attractive technique to combat interference in multiple-input multiple-output systems because it reduces costs and power consumption in the receiver equipment. Most of the frequency division duplex systems with linear precoding acquire the channel state information at the receiver by using supervised algorithms. Such algorithms make use of pilot symbols periodically sent by the transmitter. In a later step, the channel state information is sent to the transmitter side through a limited feedback channel. In order to reduce the overhead inherent to the periodical transmission of training data, we propose to acquire the channel state information by combining supervised and unsupervised algorithms, leading to a hybrid and more efficient approach. Simulation results show that the performance achieved with the proposed scheme is clearly better than that with standard algorithms.Consellería de Economía e Industria; 09TIC008105PRMinisterio de Educación y Ciencia; TEC2007-68020-C04-0

    DASBE: Decision-Aided Semi-Blind Equalization for MIMO Systems with Linear Precoding

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    [Abstract] Multiple-Input Multiple-Output (MIMO) digital communications standards usually acquire Channel State Information (CSI) by means of supervised algorithms, which implies a loss of performance since pilot symbols do not convey information. We propose to obtain this CSI by using the so-called semi-blind techniques, which combine both supervised and unsupervised (blind) methods. The key idea consists in introducing a decision criterion to determine when the channel has suffered a significant change. In such a case, transmission of pilot symbols is required. The use of this criterion also allows us to determine the time instants in which CSI has to be sent to the transmitter from the receiver through a low-cost feedback channel.Ministerio de Ciencia e Innovación; 09TIC008105PRMinisterio de Ciencia e Innovación; TEC2007-68020-C04-01Ministerio de Ciencia e Innovación; CSD2008-0001
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