南京出租车遭遇移花接木

日前,南京的哥王先生和同行们分别向南京金陵交运出租公司缴纳了10万元的购车款,可等到签合同的时候,才被告知,要想继续开出租车,还要先签订一个补充协议。王先生说他们是10．8万缴的购车款,叫我们必须签补充协议,等于强行借我们的钱（购车款）,而这个车就属于公司了,要公车公营了。王先生到出租车公司谈的时候,公司经理说签完合同就成劳动关系了,就是司机承包公司的车,“车款是司机交的,算是公司从司机手里借钱”,经理说。王先生说如果不自愿借行不行？公司经理说不行。     

景德镇出租车"变脸"难题

出租车要不要换型?大礼包花落谁家?这些悬置的问题确实让瓷都出租车业掀起了一些波澜。最近一段时间,"瓷都"景德镇的大街小巷都在谈论同一个话题——出租车升级换车,是换利亚纳、捷达还是桑塔纳?种种猜测、争论不绝于耳。据悉,这次换车将涉及景德镇市正在运营的595辆出租车。9月7日,景德镇市举行了出租车更新换型听证会,结果外地车型选票领先,而本地纳税大户昌河汽车却遭到冷落。     

小排量车遭遇“中国式”消费尴尬

近期，市场知名研究机构的报告还表明，无论是第一次购车，还是已有车近期准备更换的消费者，小排量车都非他们的首选。所以，政府和媒体大力宣传的小排量车应该优先发展的舆论导向，对于心理上还是“以大为美”的中国消费者来说，多少有些“一厢情愿”的味道。     

出租车与"公交优先"待遇

出租车是否属于“公共交通”性质?出租车到底是社会车辆还是“公交车辆”?本文认为,出租车享受“公交优先”待遇是确凿无疑的。     

关键词：油改气

中国交通新闻网：诸暨运管局近日查获了两辆擅自“油改气”教练年。据诸暨运管局稽查人员介绍,教练车未经过相关部门的严格审批和检测,私自进行改装的,属于违法行为。他们已对这两辆教练车的改装装置进行了拆除,并将根据相应法律法规做出严肃处罚。     

由"出走"思索中高档出租车市场

2006年1月8日晚上10点多,杭州7辆奔驰出租车的河南籍司机在杭州大众出租车公司不知情的情况下,连夜"逃回"河南,把"奔的"直接开到当地公安局集体"自首".     

汽车消费税新政迎来小排量出租车"松绑"

小排量出租车! --百度一下,找到相关网页约135,000篇,用时0.066秒,关于<为何容不下小排量出租车>的网络质疑在各大门户网站也被转载.     

公路客运遭遇铁路"风时代"

2007年4月18日,我国铁路第六次大提速,此举引起了交通运输业界不小的震动,它预示着交通运输格局会随之改变。屡屡承受巨大压力的公路客运企业,在大提速的震慑之下,"睡狮渐已醒",出现了一批先知先觉的客运业者,意识到公路客运行业面临着再次的调整。笔者认为,这次大提速对公路客运的影响还只是暂时的、局部的,真正要面临着行业洗牌的是"十一五"之后的"十二五"。那时,在完善的铁路网之上,一个快速铁路客运网将脱胎而成,铁老大要夺回的不仅是公路客运占据的地盘,民航也可能会被迫让出自己的份额。     

"拥堵费"为什么遭遇民意阻击?

进入21世纪以来,我国大部分一线城市相继陷入交通拥堵的困局.据调查表明,我国百万人口以上城市有80%路段和90%的路口通行能力已接近极限. 为了解决拥堵带来的难题,有关城市管理者们把目光聚焦在了限制私家车出行上,鼓励市民采用公共交通出行.     

镇江市天然气汽车推广应用分析研究

本文以镇江市天然气汽车的推广应用情况和配套设施情况为基础,分析天然气汽车推广应用存在的问题,有针对性地提出推广应用天然气汽车的政策建议。     

Nonlinear pricing of taxi services

This paper examines the effects of nonlinear fare structures in taxi markets using an extended taxi model with an explicit consideration of perceived profitability. The expected profit, defined as the profit per unit time (inclusive of both occupied and vacant taxi times), that a taxi driver expects to receive from picking up a customer in a particular zone or location, has great impact on the taxi driver’s choice of location in the search for customers. The fare structure directly governs the profitability of taxi rides of different distances originating from different locations. With these explicit considerations, the extended model is intended to look into the market effects of adopting a nonlinear fare structure with declining incremental charges. The proposed nonlinear fare structure could help restore a level-playing field for taxi operators whose businesses have been affected by some taxi drivers who resort to practices such as offering fare discounts or accepting requests for discounted fares from passengers for long-haul trips. Analysis of sensitivity of social welfare and profit gain as well as taxi/customer wait/search times is conducted with respect to the parameters in the nonlinear fare structure for the Hong Kong taxi market, and Pareto-improving nonlinear fare amendments are identified that neither disadvantage any customer nor reduce the taxi operators’ profits.     

Short-term planning of liquefied natural gas deliveries

The ability of a supplier of liquefied natural gas (LNG) to deliver cargoes at desired times, while effectively managing a fleet of cryogenic vessels can significantly impact its profits. We investigate in this paper an LNG short-term delivery planning problem by considering mandatory cargoes as well as optional cargoes to select, along with the scheduling of a heterogeneous vessel fleet with controllable cruising speeds. Several technical constraints are accommodated including time windows, berth availability, bunkering restrictions, inventory, liquefaction terminal storage capacity, maximum waiting time, and planned maintenance restrictions. The objective is to maximize the net profit.We propose a mixed-integer programming formulation that includes a polynomial number of variables and constraints and accommodates all of the problem features. Also, we describe an optimization-based variable neighborhood search procedure that embeds the proposed compact formulation. To assess the quality of the generated solutions, we propose a second valid formulation with an exponential number of decision variables and we solve its linear programming relaxation using column generation. We provide the results of extensive computational results that were carried out on a set of large-scale set of realistic instances, with up to 62 vessels and 160 cargoes, provided by a major LNG producer. These results provide evidence that the proposed improvement procedure yields high-quality solutions.     

Optimal planning of liquefied natural gas deliveries

We investigate the problem of designing an optimal annual delivery plan for Liquefied Natural Gas (LNG). This problem requires determining the long-term cargo delivery dates and the assignment of vessels to the cargoes while accommodating several constraints, including berth availability, liquefaction terminal inventory, planned maintenance, and bunkering requirements. We describe a novel mixed-integer programming formulation that captures important industry requirements and constraints with the objective of minimizing the vessel fleet size. A peculiar property of the proposed formulation is that it includes a polynomial number of variables and constraints and is, in our experience, computationally tractable for large problem instances using a commercial solver. Extensive computational runs demonstrate the efficacy of the proposed model for real instances provided by a major energy company that involve up to 118 cargoes and a 373-day planning horizon.     

Environmental benefits of natural gas for buses

This paper presents a life cycle assessment comparing diesel buses with buses fueled by natural gas. The data for the emission of pollutants are based on the MEET Project of the European Commission (EC), supplemented by data measured for diesel and gas buses in Paris. The benefits of the gas fueled bus are then quantified using the damage cost estimates of the ExternE Project of the EC. A diesel bus with emissions equal to Standard EURO2 of the EC is compared with the same bus equipped with a natural gas engine, for use in Paris and in Toulouse. The damage cost of a diesel bus is significant, in the range of 0.4–1.3

/km. Natural gas allows an appreciable reduction of the emissions, lowering the damage cost by a factor of about 2.5 (Toulouse) to 5.5 (Paris). An approximate rule is provided for transferring the results to other cities. A sensitivity analysis is carried out to evaluate the effect of the evolution of the emissions standard towards EURO3, 4 and 5, as well as the effect of uncertainties. Finally a comparison is presented between a EURO2 diesel bus with particle filter, and a gas fueled bus with the MPI engine of IVECO, a more advanced and cleaner technology. With this engine the damage costs of the gas fueled bus are about 3–5 times lower than those of the diesel with particle filter, even though the latter has already very low emissions.     

Analysis of taxi demand and supply in New York City: implications of recent taxi regulations

This paper investigates temporal and weather-related variation in taxi trips in New York City. A taxi trip data-set with 147 million records covering 10 months of activity is used. It is shown that there are substantial variations in ridership, taxi supply, trip distance, and pickup frequency for different time periods and weather conditions. These variations, in turn, cause variations in driver revenues which is one of the main measures of taxi supply–demand equilibrium. The findings are then used to discuss the anticipated impacts of two recently enacted taxi regulation changes: the first fare increase since 2006 and the E-Hail pilot program which allows taxi hailing with smart phone applications. The fare increase is estimated to cause varying levels of revenue increase for different time periods. E-Hail apps are not expected to offer considerable improvements at all times, but rather when both adequate taxi supply and demand occur simultaneously.     

Airport taxi planning: Lagrangian decomposition

The airport taxi planning (TP) module is a decision tool intended to guide airport surface management operations. TP is defined by a flow network optimization model that represents flight ground movements and improves aircraft taxiing routes and schedules during periods of aircraft congestion. TP is not intended to operate as a stand‐alone tool for airport operations management: on the contrary, it must be used in conjunction with existing departing and arriving traffic tools and overseen by the taxi planner of the airport, also known as the aircraft ground controller. TP must be flexible in order to accommodate changing inputs while maintaining consistent routes and schedules already delivered from past executions. Within this dynamic environment, the execution time of TP may not exceed a few minutes. Classic methods for solving binary multi‐commodity flow networks with side constraints are not efficient enough; therefore, a Lagrangian decomposition methodology has been adapted to solve it. We demonstrate TP Lagrangian decomposition using actual data from the Madrid‐Barajas Airport. Copyright © 2011 John Wiley & Sons, Ltd.     

A hybrid heuristic strategy for liquefied natural gas inventory routing

As liquefied natural gas (LNG) steadily grows to be a common mode for commercializing natural gas, LNG supply chain optimization is becoming a key technology for gas companies to maintain competitiveness. This paper develops methods for improving the solutions for a previously stated form of an LNG inventory routing problem (LNG-IRP). Motivated by the poor performance of a Dantzig-Wolfe-based decomposition approach for exact solutions, we develop a suite of advanced heuristic techniques and propose a hybrid heuristic strategy aiming to achieve improved solutions in shorter computational time. The heuristics include two phases: the advanced construction phase is based on a rolling time algorithm and a greedy randomized adaptive search procedure (GRASP); and the solution improvement phase is a series of novel MIP-based neighborhood search techniques. The proposed algorithms are evaluated based on a set of realistic large-scale instances seen in recent literature. Extensive computational results indicate that the hybrid heuristic strategy is able to obtain optimal or near optimal feasible solutions substantially faster than commercial optimization software and also the previously proposed heuristic methods.     

Equilibrium properties of taxi markets with search frictions

The equilibrium properties of an aggregate taxi market are investigated using a general bilateral searching and meeting function which characterizes the search frictions between vacant taxis and unserved customers. Three specific issues are analyzed for meeting functions that exhibit increasing, constant and decreasing returns to scale. Firstly, service quality in terms of customer wait/search time and average profit per taxi are examined jointly in relation to taxi fleet size, and a Pareto-improving win-win situation is identified, where an increase in taxi fleet size leads to improvements in both service quality and market profitability. Such a Pareto-improving situation is found to emerge if and only if the meeting functions show increasing returns to scale. Secondly, the properties of the socially optimal solution are examined. It is found that the taxi fleet size should be chosen such that the total cost of operating vacant taxis equals the total cost of customer waiting time multiplied by an asymmetric factor of the meeting function, and that taxi services should be subsidized at social optimum only when the meeting functions show increasing returns to scale. Thirdly, the Pareto-efficient services are examined for trade-offs between social welfare and profits in the light of partially conflicting objectives of the public sector and the private taxi firms using a bi-objective maximization approach. The taxi utilization rate and the customer wait/search time or service quality are proved to be constant along the Pareto frontier and equal to those at social optimum if the meeting functions show constant returns to scale. Extensions are made to the cases with increasing and decreasing returns to scale.     

Analogy of fixed route shared taxi (taxi khattee) and bus services under various demand density and economical conditions

Taxi khattee is a fixed route unregulated shared taxi. It is a very common mode of transportation in Iran. Fixed route, unscheduled operation, open, unlimited pick‐up and drop‐off locations, and share ride are common features of taxi khattees. Low passenger capacity and working in high demand corridors provides for the possibility of high service frequencies any time of the day. Taxi khattees are similar to jitneys, which are obsolete or illegal in many countries. The aim of this research is to design transit network of an area using taxi khattees in addition to buses. The methodology employed in this paper simultaneously considers the costs to the users and operators on the one hand, and those of the public non‐users on the other hand. Taxi khattees are used in the design of a multimodal network along with buses to characterize the appropriate economic domain for their use. Moreover, their operation indices are compared against those of buses. A sensitivity analysis is carried out on various performance measures. Results show taxi khattees should be used in areas where population density is low, work force is inexpensive, social costs are not considered in fare calculation, and users' value of time is high. The study contradicts the common belief that since taxi khattees provide a high frequency compared to buses, they are economically plausible to use in a transit fleet. Copyright © 2011 John Wiley & Sons, Ltd.