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111.
The value of travel time savings (VTTS) accounts for a majority of the total user benefits in economic appraisal of transport investments. This means that having an accurate estimate of VTTS for different segments of travel continues to retain currency, despite there being a rich literature on estimates of VTTS for different travel modes, travel purposes, income groups, life cycles, and distance bands. In contrast, there is a dearth of research and evidence on vehicle VTTS, although joint travel by car is an important segment of travel. This paper fills this gap by developing a group-based modelling approach to quantify the vehicle VTTS and compares this with the VTTS for a driver with and without a passenger. An online survey was conducted in Sydney in 2014 and the data used to obtain a number of new empirical estimates of vehicle and driver VTTS. The new evidence questions the validity of various assumptions adopted in current practice for valuing the time savings of car passengers and multiple occupant cars.  相似文献   
112.
首先介绍两种被铁路工程广泛应用于经济运距分界点确定的最大距离相等法和平均运距相等法,并对这两种方法的直观性和正确性提出疑问。为合理确定经济运距分界点,在假定条件一致的情况下,从理论上提出用微积分的方法来解决此问题。然后将微积分法与最大距离相等法和平均运距相等法进行对比分析,得出原来使用的两种方法的前提和结论之间没有直观的因果关系,而平均运距相等法在理论上就是错误的结论。  相似文献   
113.
The workshop included presentations of nine papers covering very different types of situations and transitions. Some papers were region specific (Russia, Middle East, Asia, Europe, and two from Latin America) and others were of general applicability. The discussion highlights that virtually all cities and regions will go through one type of transition or another, sooner or later, and that the study of such transitions provides a very rich learning environment. The most important conclusion has been that in many cases the stability of supply and accessibility to public transport by all population segments is more important than competition and ownership.  相似文献   
114.
穆子奇 《北方交通》2006,(6):200-202
通过分析公路工程质量成本及质量成本的关系,表明提高工程质量是降低成本的一种重要方法。  相似文献   
115.
从重大恶性事故,职业灾害伤亡总数,职业危害,经济损失4个方面讨论了我国的职业灾害问题,并提出职业灾害控制措施。  相似文献   
116.
The steady sailing performance of a sail-assisted bulk carrier is investigated utilising towing-tank derived hydrodynamic derivatives and wind tunnel measured aerodynamic properties of the sails and the ship. The aerodynamic characteristics investigated include the ship hull at the fully-loaded draught, the sail–sail interaction effects for two sets of four identical hybrid-sails, and the sail–hull interaction effects for the same two sets of identical sails in the presence of the selected bulk carrier hull-form. This is in addition to lift–drag measurements of single isolated sails of each shape. The form of the two sets of soft sails was rectangular and triangular. This paper is concerned with assessing the benefits of a sail-assisted ship operation, and hence a steady-state rather than complete time-domain integrations of the governing equations are reported. The results of the completed analysis suggest that the benefits of the derived sail generated driving force are greater than the overhead of equipping the ship with a selected system of hybrid-sails. Sail-assisted ships could represent an important contribution to an improving global environment by reducing the demands for a driving force through the propeller.  相似文献   
117.
The transition to electric vehicles (EV) faces two major barriers. On one hand, EV batteries are still expensive and limited by range, owing to the lack of technology breakthrough. On the other hand, the underdeveloped supporting infrastructure, particularly the lack of fast refueling facilities, makes EVs unsuitable for medium and long distance travel. The primary purpose of this study is to better understand these hurdles and to develop strategies to overcome them. To this end, a conceptual optimization model is proposed to analyze travel by EVs along a long corridor. The objective of the model is to select the battery size and charging capacity (in terms of both the charging power at each station and the number of stations needed along the corridor) to meet a given level of service in such a way that the total social cost is minimized. Two extensions of the base model are also considered. The first relaxes the assumption that the charging power at the stations is a continuous variable. The second variant considers battery swapping as an alternative to charging. Our analysis suggests that (1) the current paradigm of charging facility development that focuses on level 2 charging delivers poor level of service for long distance travel; (2) the level 3 charging method is necessary not only to achieve a reasonable level of service, but also to minimize the social cost; (3) investing on battery technology to reduce battery cost is likely to have larger impacts on reducing the charging cost; and (4) battery swapping promises high level of service, but it may not be socially optimal for a modest level of service, especially when the costs of constructing swapping and charging stations are close.  相似文献   
118.
Among the most important trade-related issues currently confronting the UK are the environmental implications of very large volumes of containerised freight being handled at a small number of ports while there appears to be significant potential for using other ports and water-rail intermodal connections. Six UK ports are selected for the analysis: Hull/Immingham, Liverpool, Felixstowe, Southampton, Dover and Bristol. Through an origin-destination analysis, the cost and CO2e impacts of UK port trade patterns are compared using the actual situation against three proposed Scenarios: (1) the re-direction of containers by a combined expansion of Hull and Immingham; Liverpool; and Bristol, (2) moving containers by rail facilitated via expanded capacity at Southampton, and (3) moving containers by rail through expanded capacity at Felixstowe. The research found that transporting containers from Felixstowe and Southampton to the northern regions by rail has the lowest CO2e impact, and is the most feasible option, although constraints exist in terms of infrastructure provision, water depth and rail network capacity.  相似文献   
119.
The transportation sector faces increasing challenges related to energy consumption and local and global emissions profiles. Thus, alternative vehicle technologies and energy pathways are being considered in order to overturn this trend and electric mobility is considered one adequate possibility towards a more sustainable transportation sector.In this sense, this research work consisted on the development of a methodology to assess the economic feasibility of deploying EV charging stations (Park-EV) by quantifying the tradeoff between economic and energy/environmental impacts for EV parking spaces deployment. This methodology was applied to 4 different cities (Lisbon, Madrid, Minneapolis and Manhattan), by evaluating the influence of parking premium, infrastructure cost and occupancy rates on the investment Net Present Value (NPV). The main findings are that the maximization of the premium and the minimization of the equipment cost lead to higher NPV results. The NPV break-even for the cities considered is more “easily” reached for higher parking prices, namely in the case of Manhattan with the higher parking price profile. In terms of evaluating occupancy rates of the EV parking spaces, shifting from a low usage (LU) to a high usage (HU) scenario represented a reduction in the premium to obtain a NPV = 0 of approximately 14% for a 2500 € equipment cost, and, in the case of a zero equipment cost (e.g. financed by the city), a NPV = 0 was obtained with approximately a 2% reduction in the parking premium. Moreover, due to the use of electric mobility instead of the average conventional technologies, Well-to-Wheel (WTW) gains for Lisbon, Madrid, Minneapolis and Manhattan were estimated in 58%, 53%, 52% and 75% for energy consumption and 66%, 75%, 62% and 86% for CO2 emissions, respectively.This research confirms that the success of deploying an EV charging stations infrastructure will be highly dependent on the price the user will have to pay, on the cost of the infrastructure deployed and on the adhesion of the EV users to this kind of infrastructure. These variables are not independent and, consequently, the coordination of public policies and private interest must be promoted in order to reach an optimal solution that does not result in prohibitive costs for the users.  相似文献   
120.
Fishing communities, the Government of Thailand Department of Fisheries, local nongovermnental organizations, universities, the Food and Agriculture Organization of the United Nations (FAO), and FAO's Bay of Bengal Program have undertaken a partnership in management of Phang-nga Bay's coastal resources. It is the first project of its kind in Thailand, and although still in the early stages, offers insights that may contribute to our knowledge of how we can improve our management of coastal resources, including the importance of (1) building relationships within the governance process; (2) combining education, enforcement, and economic incentives to achieve compliance; (3) implementing solutions early; and (4) government support of community-based decisions. These insights reinforce trends emerging in other coastal management projects in the Asian region.  相似文献   
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