成品油税费改革对西部道路客货运输的影响及对策

国家实行成品油税费改革,给西部道路客货运输业的发展带来了机遇和挑战。文章从道路运输管理部门和道路客货运输企业的角度阐述成品油税费改革对行业管理与企业发展的机遇和挑战,并结合实际提出了应对策略与建议。     

Modelling the impact of weather conditions on active transportation travel behaviour

Three weather sensitive models are used to explore the relationship between weather and home-based work trips within the City of Toronto, focusing on active modes of transportation. The data are restricted to non-captive commuters who have the option of selecting among five basic modes of auto driver, auto passenger, transit, bike and walk. Daily trip rates in various weather conditions are assessed. Overall, the results confirm that impact of weather on active modes of transportation is significant enough to deserve attention at the research, data collection and planning levels.     

Factors influencing travel mode choice among families with young children (aged 0–4): a review of the literature

Life events, such as the birth of a child, disrupt habitual travel behaviour and provide a valuable opportunity to influence the adoption of sustainable transport practices. However, in order for sustainable travel practices to be adopted, an understanding is required of the factors that influence travel mode choice among families with young children. Research in this field is particularly timely given many in the millennial generation, a comparably large cohort, are approaching this life stage. This comprehensive literature review develops a framework of factors influencing travel mode choice among families with young children. The findings reveal a multitude of factors influence decisions about mode choice, and, in particular, encourage travel by car, when travelling with young children. The paper concludes with an agenda for future research about travel among families with young children, a largely overlooked group of transport users.     

长江口南汇边滩短期冲淤变化分析

南汇边滩位于长江口和杭州湾的交汇地带,受长江口和杭州湾北岸两股潮流的控制,近年来由于低潮滩促淤围垦工程导致其水流和泥沙运移、沉积和地貌发生了显著的变化。根据2006—2008年南汇边滩测图及2007年11月—2008年11月每个季度的9个断面测量资料,结合区域内的泥沙沉积特征,探讨南汇边滩对周边涉水围垦工程和流域来水来沙变异做出适应性地貌耦合过程之后的近期冲淤演变规律,着重探讨季节性冲淤特征。结果表明:年度上南汇东滩以淤长为主,南汇南滩以冲刷为主。不同季节南汇边滩冲淤变化过程存在很大差异:平面上,南汇边滩等深线夏、冬季以淤进为主,春、秋季以蚀退为主;垂向上,南汇东滩断面呈春夏秋冲淤交替、冬季淤积的态势,南汇嘴断面呈秋季冲刷、冬夏季淤积的态势,而位于南汇南滩的断面则呈秋冬季冲刷、春夏季淤积态势。南汇东滩沉积物粒径总体上较细,东滩与南滩交汇处的南汇嘴附近中值粒径相对较粗,南汇南滩浅滩沉积物颗粒中值粒径最粗。     

城市快速路匝道最小间距模型

匝道间距是路线设计中的重要内容,对交通流有决定性的影响。根据城市快速匝道的特点,应用驾驶员行为理论,模拟了驾驶员城市快速匝道上的驾驶行为。认为匝道间距是影响城市快速路主线运行状况的关键因素。为了合理确定匝道最小间距,必须确定匝道组合模式和计算匝道加减速车道长度,并计算出车流从匝道汇入主线后,由于车流变道而形成交织车流长度。由此建立了不同匝道组合模式下的匝道最小间距模型。应用实例表明。当匝道间距不能满足最小间距时,车速降低,服务水平下降。     

带有最优流量记忆时间差的一类新格子模型

为了分析最优流量记忆时间差对交通流稳定性的影响,本文基于考虑驾驶员估计得到的最优流量信息,同时考虑驾驶员在驾车过程中受到记忆时间的影响,给出了一类新的格子流体动力学模型.首先,基于线性稳定性理论,获得了新模型的稳定性条件;随后,通过非线性分析方法,给出该模型的mKdV方程;然后,基于求解上述方程所得到的扭结-反扭结孤立波可用于描述交通拥挤的转化和传播过程.最后,通过仿真算例验证了上述理论分析的结论,即驾驶员的记忆时间和最优流量记忆时间差能够显著影响交通流的稳定性,同时增大记忆时间步长和强度系数可以有效地增强交通流的稳定性.     

Port authorities view state coastal management programs

Abstract

An estuarine sanctuary is a store of public values due to the ecological, cultural, recreational, aesthetic, historic, and economic services provided by the preserve. These values may be expected to increase over time because of (1) growth in the population demanding estuarine services, (2) growth in the willingness to pay for such services, and (3) growth in the actual quality and quantity of services which are provided by a protected natural system. Thus an estuarine sanctuary will be more valuable to future generations than to current generations. When weighing the cost and benefits of a preservation or development decision, a preservation decision which seems currently undesirable may in fact be socially beneficial when growth in the value of estuarine services is included.     

浅谈公路工程估算编制的新规则

新的《公路工程基本建设项目投资估算编制办法》和《公路工程估算指标》自2012年1月1日正式实施。取代1996编办和指标,针对估算编制的新规则,分析总结新旧差异,为以后估算编制工作提供指导。     

Evolution of the household vehicle fleet: Anticipating fleet composition, PHEV adoption and GHG emissions in Austin, Texas

In today’s world of volatile fuel prices and climate concerns, there is little study on the relationship between vehicle ownership patterns and attitudes toward vehicle cost (including fuel prices and feebates) and vehicle technologies. This work provides new data on ownership decisions and owner preferences under various scenarios, coupled with calibrated models to microsimulate Austin’s personal-fleet evolution.Opinion survey results suggest that most Austinites (63%, population-corrected share) support a feebate policy to favor more fuel efficient vehicles. Top purchase criteria are price, type/class, and fuel economy. Most (56%) respondents also indicated that they would consider purchasing a Plug-in Hybrid Electric Vehicle (PHEV) if it were to cost $6000 more than its conventional, gasoline-powered counterpart. And many respond strongly to signals on the external (health and climate) costs of a vehicle’s emissions, more strongly than they respond to information on fuel cost savings.Twenty five-year simulations of Austin’s household vehicle fleet suggest that, under all scenarios modeled, Austin’s vehicle usage levels (measured in total vehicle miles traveled or VMT) are predicted to increase overall, along with average vehicle ownership levels (both per household and per capita). Under a feebate, HEVs, PHEVs and Smart Cars are estimated to represent 25% of the fleet’s VMT by simulation year 25; this scenario is predicted to raise total regional VMT slightly (just 2.32%, by simulation year 25), relative to the trend scenario, while reducing CO₂ emissions only slightly (by 5.62%, relative to trend). Doubling the trend-case gas price to $5/gallon is simulated to reduce the year-25 vehicle use levels by 24% and CO₂ emissions by 30% (relative to trend).Two- and three-vehicle households are simulated to be the highest adopters of HEVs and PHEVs across all scenarios. The combined share of vans, pickup trucks, sport utility vehicles (SUVs), and cross-over utility vehicles (CUVs) is lowest under the feebate scenario, at 35% (versus 47% in Austin’s current household fleet). Feebate-policy receipts are forecasted to exceed rebates in each simulation year.In the longer term, gas price dynamics, tax incentives, feebates and purchase prices along with new technologies, government-industry partnerships, and more accurate information on range and recharging times (which increase customer confidence in EV technologies) should have added effects on energy dependence and greenhouse gas emissions.     

基于道路特征信息变化率的公路线形质量评价

公路线形质量对行车的舒适性和安全性有着非常重要的影响，如何合理有效地对其进行评价是一个有待解决的问题。从驾驶员行车时接受道路信息的角度出发，提出了道路特征信息变化率的概念，并作为评价公路线形质量的定量指标运用到平面线形、纵断面线形和平纵组合的评价研究中。研究表明：平曲线半径越小，驾驶员接受的道路特性信息变化率越大，驾驶员负担也越重；此外，平曲线长度、竖曲线半径及平纵组合都对道路特性信息变化率有较大的影响。研究成果可为改善公路线形，提高行车安全提供依据。