981 resultados para Light rail vehicles.


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Federal Railroad Administration, Office of Research and Development, Washington, D.C.

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Federal Railroad Administration, Office of Research and Development, Washington, D.C.

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Motor vehicles are major emitters of gaseous and particulate pollution in urban areas, and exposure to particulate pollution can have serious health effects, ranging from respiratory and cardiovascular disease to mortality. Motor vehicle tailpipe particle emissions span a broad size range from 0.003-10µm, and are measured as different subsets of particle mass concentrations or particle number count. However, no comprehensive inventories currently exist in the international published literature covering this wide size range. This paper presents the first published comprehensive inventory of motor vehicle tailpipe particle emissions covering the full size range of particles emitted. The inventory was developed for urban South-East Queensland by combining two techniques from distinctly different disciplines, from aerosol science and transport modelling. A comprehensive set of particle emission factors were combined with traffic modelling, and tailpipe particle emissions were quantified for particle number (ultrafine particles), PM1, PM2.5 and PM10 for light and heavy duty vehicles and buses. A second aim of the paper involved using the data derived in this inventory for scenario analyses, to model the particle emission implications of different proportions of passengers travelling in light duty vehicles and buses in the study region, and to derive an estimate of fleet particle emissions in 2026. It was found that heavy duty vehicles (HDVs) in the study region were major emitters of particulate matter pollution, and although they contributed only around 6% of total regional vehicle kilometres travelled, they contributed more than 50% of the region’s particle number (ultrafine particles) and PM1 emissions. With the freight task in the region predicted to double over the next 20 years, this suggests that HDVs need to be a major focus of mitigation efforts. HDVs dominated particle number (ultrafine particles) and PM1 emissions; and LDV PM2.5 and PM10 emissions. Buses contributed approximately 1-2% of regional particle emissions.

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President’s Report Hello fellow AITPM members, First I would like on behalf of all AITPM members to send our condolences to all who have been affected by February’s tragic bushfires in regional Victoria, and deliver our best wishes to all of those involved in the rebuilding efforts. Over time I expect that the Victorian Government’s Royal Commission will analyse the circumstances and put forward a range of measures which will improve fire safety in vulnerable areas. As transport professionals it will be important for us to consider the findings and look to undertaking any recommendations that relate to the work we do. Not only in Victoria, but nationwide. In particular, the importance of logistics was highlighted following the fire events. Donors across Australia were this time requested to donate money rather than goods, presumably due in part to problems associated with the transport system coping with additional uncoordinated freight load, whilst being needed to support emergency management vehicle and managed freight movements. Notwithstanding, it was wonderful to see otherwise difficult to obtain goods, such as animal feed, being donated from far afield and transported in kind by trucking operators. As stated in last month’s Newsletter, AITPM made a direct cash donation to the Red Cross Bushfire Appeal immediately following the events, and a further donation to the Queensland Premier’s Disaster Relief Fund to support recovery after the North Queensland floods, which claimed seven lives. Again, we will need to monitor how the rebuilding effort unfolds particularly in regional Victoria and centres including Ingham in North Queensland, but I would urge all AITPM members who are in a position to support the restoration of the affected communities to play a part, particularly over time once the initial shock subsides and the steady job of rebuilding is underway. Onto lighter matters, AITPM’s flagship event, the 2009 AITPM National Conference, Traffic Beyond Tomorrow, being held in Adelaide from 5 to 7 August, is fast approaching. www.aitpm.com has all of the details about how to register, sponsor a booth, and so forth. We are looking forward to catching up with our conference “regulars” and meeting with new folks to AITPM, and Australian traffic and transport planning and management. Adelaide is one of my favourite places to visit and I’m looking forward to riding the light rail line extension through town and checking out progress on the road system development. Best regards all, Jon Bunker

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This paper describes a thorough thermal study on a fleet of DC traction motors which were found to suffer from overheating after 3 years of full operation. Overheating of these traction motors is attributed partly because of the higher than expected number of starts and stops between train terminals. Another probable cause of overheating is the design of the traction motor and/or its control strategy. According to the motor manufacturer, a current shunt is permanently connected across the motor field winding. Hence, some of the armature current is bypassed into the current shunt. The motor then runs above its rated speed in the field weakening mode. In this study, a finite difference model has been developed to simulate the temperature profile at different parts inside the traction motor. In order to validate the simulation result, an empty vehicle loaded with drums of water was also used to simulate the full pay-load of a light rail vehicle experimentally. The authors report that the simulation results agree reasonably well with experimental data, and it is likely that the armature of the traction motor will run cooler if its field shunt is disconnected at low speeds

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Crash statistics in Singapore from 2001 to 2005 have shown that motorcycles are involved in about 54% of intersection crashes. The overall involvement of motorcycles in crashes as the not-at-fault party is about 43% but at intersections, the corresponding percentage is increased to 57%. Quasi-induced exposure estimates show that the motorcycle exposure rate at signalized intersections is 41.7% even though motorcycles account for only 19% of the vehicle population. This study seeks to examine in greater details, the problem of motorcycle exposure at signalized intersections. In particular, the exposure arising from potential crashes with red light running vehicles from the conflicting stream at four signalized intersections is investigated. The results show that motorcycles are more exposed because they tend to accumulate near the stop-line during the red phase to facilitate an earlier discharge during the initial period of the green which is the more vulnerable period. At sites where there are more weaving opportunities because the lanes are wider or where there are exclusive right-turn lanes, the accumulation is higher and hence an increased exposure is observed. The analysis also shows that the presence of heavy vehicles tends to decrease motorcycle exposure as their weaving opportunities become restricted as well as there is a greater reluctance for them to weave past or queue alongside the heavy vehicles and their effects intensify for narrower lane width.

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Transition zones between bridge decks and rail tracks suffer early failure due to poor interaction between rail vehicles and sudden changes of stiffness. This has been an ongoing problem to rail industry and yet still no systematic studies appear to have been taken to maintain a gradually smoothening transmission of forces between the bridge and its approach. Differential settlement between the bridge deck and rail track in the transition zone is the fundamental issue, which negatively impacts the rail industry by causing passenger discomfort, early damage to infrastructure and vehicle components, speed reduction, and frequent maintenance cycles. Identification of mechanism of the track degradation and factors affecting is imperative to design any mitigation method for reducing track degradation rate at the bridge transition zone. Unfortunately this issue is still not well understood, after conducting a numbers of reviews to evaluate the key causes, and introducing a wide range of mitigation techniques. In this study, a comprehensive analysis of the available literature has been carried out to develop either a novel design framework or a mitigation technique for the bridge transition zone. This paper addresses three critical questions in relation to the track degradation at transition zone: (1) what are the causes of bridge transition track degradation?; (2) what are the available mitigation techniques in reducing the track degradation rate?; (3) what are the factors affecting on poor performance of the existing mitigation techniques?. It is found that the absence of soil-water response, dynamic loading response, and behaviour of geotechnical characteristics under long-term conditions in existing track transition design frameworks critically influence on the failures of existing mitigation techniques. This paper also evaluates some of the existing design frameworks to identify how each design framework addresses the track degradation at the bridge transition zone.

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Level crossing risk continues to be a significant safety concern for the security of rail operations around the world. Over the last decade or so, a third of railway related fatalities occurred as a direct result of collisions between road and rail vehicles in Australia. Importantly, nearly half of these collisions occurred at railway level crossings with no active protection, such as flashing lights or boom barriers. Current practice is to upgrade level crossings that have no active protection. However, the total number of level crossings found across Australia exceed 23,500, and targeting the proportion of these that are considered high risk (e.g. public crossings with passive controls) would cost in excess of AU$3.25 billion based on equipment, installation and commissioning costs of warning devices that are currently type approved. Level crossing warning devices that are low-cost provide a potentially effective control for reducing risk; however, over the last decade, there have been significant barriers and legal issues in both Australia and the US that have foreshadowed their adoption. These devices are designed to have significantly lower lifecycle costs compared with traditional warning devices. They often make use of use of alternative technologies for train detection, wireless connectivity and solar energy supply. This paper describes the barriers that have been encountered for the adoption of these devices in Australia, including the challenges associated with: (1) determining requisite safety levels for such devices; (2) legal issues relating to duty of care obligations of railway operators; and (3) issues of Tort liability around the use of less than fail-safe equipment. This paper provides an overview of a comprehensive safety justification that was developed as part of a project funded by a collaborative rail research initiative established by the Australian government, and describes the conceptual framework and processes being used to justify its adoption. The paper provides a summary of key points from peer review and discusses prospective barriers that may need to be overcome for future adoption. A successful outcome from this process would result in the development of a guideline for decision-making, providing a precedence for adopting low-cost level crossing warning devices in other parts of the world. The framework described in this paper also provides relevance to the review and adoption of analogous technologies in rail and other safety critical industries.

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Seat belts are one of the most effective passive safety features in vehicles and there is a host of research literature attesting to the effectiveness of seat belts in protecting against death and injury. Even when use rates are high the potential gains in trauma reduction from further improvements in wearing rates are substantial. However, those currently most resistant to restraint use have also proven most difficult to target using conventional countermeasures. It is necessary to address the issues of non-wearing in order to achieve further gains in seat belt wearing. This study provide evidence-based recommendations for the way forward to tackle the problems of adult restraint non-use in light passenger vehicles in the short, medium and longer term in Australia. While there are substantial issues to be addressed for these groups, these are outside the scope of this study.

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Map-matching algorithms that utilise road segment connectivity along with other data (i.e.position, speed and heading) in the process of map-matching are normally suitable for high frequency (1 Hz or higher) positioning data from GPS. While applying such map-matching algorithms to low frequency data (such as data from a fleet of private cars, buses or light duty vehicles or smartphones), the performance of these algorithms reduces to in the region of 70% in terms of correct link identification, especially in urban and sub-urban road networks. This level of performance may be insufficient for some real-time Intelligent Transport System (ITS) applications and services such as estimating link travel time and speed from low frequency GPS data. Therefore, this paper develops a new weight-based shortest path and vehicle trajectory aided map-matching (stMM) algorithm that enhances the map-matching of low frequency positioning data on a road map. The well-known A* search algorithm is employed to derive the shortest path between two points while taking into account both link connectivity and turn restrictions at junctions. In the developed stMM algorithm, two additional weights related to the shortest path and vehicle trajectory are considered: one shortest path-based weight is related to the distance along the shortest path and the distance along the vehicle trajectory, while the other is associated with the heading difference of the vehicle trajectory. The developed stMM algorithm is tested using a series of real-world datasets of varying frequencies (i.e. 1 s, 5 s, 30 s, 60 s sampling intervals). A high-accuracy integrated navigation system (a high-grade inertial navigation system and a carrier-phase GPS receiver) is used to measure the accuracy of the developed algorithm. The results suggest that the algorithm identifies 98.9% of the links correctly for every 30 s GPS data. Omitting the information from the shortest path and vehicle trajectory, the accuracy of the algorithm reduces to about 73% in terms of correct link identification. The algorithm can process on average 50 positioning fixes per second making it suitable for real-time ITS applications and services.

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Este trabalho visa determinar a contribuição das emissões evaporativas provenientes dos veículos leves de passageiro, para a degradação da qualidade do ar atmosférico. O objetivo principal é avaliar as concentrações compostos monoaromáticos voláteis Benzeno, Tolueno, Etilbenzeno e Xilenos (BTEX) em ambientes confinados, sendo este realizado em um local que caracterize a realidade da frota veicular da Região metropolitana do Rio de Janeiro. As amostras foram coletadas em um estacionamento subterrâneo de um Shopping Center da zona norte do Rio de Janeiro, através do sistema de amostragem ativa, utilizando cartucho de carvão ativo como adsorvente. As amostras foram extraídas com solvente orgânico e analisadas posteriormente por Cromatografia gasosa acoplada à espectrometria de massas (CGEM). As médias dos resultados obtidos foram 52,7 g.m-3 para o benzeno, 203,6 g.m-3 para o tolueno, 44,6 g.m-3 para o etilbenzeno, 115,7 g.m-3 para os xilenos, sendo o tolueno o composto encontrado em maior abundância. Esses resultados foram comparados com resultados encontrados na literatura de emissões veiculares em ambientes confinados como garagens e túneis. Foi investigada a correlação com as emissões do veículo em movimento, obtidas através de estudos previamente realizados em um túnel de grande circulação e as emissões obtidas no estacionamento subterrâneo. Através desses dados ficou demonstrada diferença das fontes de emissão.

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Organizations that leverage lessons learned from their experience in the practice of complex real-world activities are faced with five difficult problems. First, how to represent the learning situation in a recognizable way. Second, how to represent what was actually done in terms of repeatable actions. Third, how to assess performance taking account of the particular circumstances. Fourth, how to abstract lessons learned that are re-usable on future occasions. Fifth, how to determine whether to pursue practice maturity or strategic relevance of activities. Here, organizational learning and performance improvement are investigated in a field study using the Context-based Intelligent Assistant Support (CIAS) approach. A new conceptual framework for practice-based organizational learning and performance improvement is presented that supports researchers and practitioners address the problems evoked and contributes to a practice-based approach to activity management. The novelty of the research lies in the simultaneous study of the different levels involved in the activity. Route selection in light rail infrastructure projects involves practices at both the strategic and operational levels; it is part managerial/political and part engineering. Aspectual comparison of practices represented in Contextual Graphs constitutes a new approach to the selection of Key Performance Indicators (KPIs). This approach is free from causality assumptions and forms the basis of a new approach to practice-based organizational learning and performance improvement. The evolution of practices in contextual graphs is shown to be an objective and measurable expression of organizational learning. This diachronic representation is interpreted using a practice-based organizational learning novelty typology. This dissertation shows how lessons learned when effectively leveraged by an organization lead to practice maturity. The practice maturity level of an activity in combination with an assessment of an activity’s strategic relevance can be used by management to prioritize improvement effort.

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This paper presents a comparison of impact dynamic performance between articulated trains and non-articulated trains. This is carried out by investigation of the characteristics of the two trains types and analysis of their effects on impact dynamics. The analysis shows that the differences in bogie support positions on the carbody and coupling devices lead to differences in several structural and compositional characteristics. These characteristics result in different impact responses for the two types of train and are directly related to their impact stablity. Articulated trains have stiff connection and integral performance in collisions but with less capability for absorbing impact energy between carriages, whereas non-articulated trains show loose connection and scattered performance in collisions but with more options for energy absorber installation between carriages.