Urban pollution and road infrastructure: A case study of China

Urban road infrastructure is crucial in affecting air pollution. Yet, little is known about the roles played by road width vs road length. This paper attempts to fill this gap by estimating the effects of road infrastructure on PM₁₀ using city-level data from China. Our robust modeling results show that the road density index, defined as the ratio of road surface area to city territory size, is negatively correlated with PM₁₀. More importantly, when the road width and length components of the road density variable are separately included in the regression models, the width is found to be significantly and negatively correlated with PM₁₀, whereas the correlation with the length variable is insignificant. This is expected as increases in road width can help mitigate congestion, improve fuel efficiency, and thus reduce emissions. On the contrary, extending roads to new or unconnected areas is likely to bring more vehicles onto the roads and extend average driving time. Our findings appeal for careful consideration of the trade-off between road width (lane numbers) and road length when planning and constructing urban road infrastructure.     

Reexamining the effect of packet pricing in the wireless internet

In this paper, we compare the market performances of circuit pricing whereby users are charged based on their length of usage time with packet pricing whereby users are charged based on the amount of information received. We show that, if packet pricing is introduced, the market price rises contrary to a widely held belief, but that the overall social welfare is unambiguously increased. Also, we show that a move to packet pricing lowers the price of multimedia transmission which requires a much higher speed, thereby increasing the usage of multimedia data in the absence of congestion, although this may not be the case in the presence of congestion.     

阶梯定价、实时定价及其潜在影响

针对实施居民用电梯度定价的决定,研究认为,此次电价调整将提高整体电价水平。阶梯定价只是一种调节收入分配的手段,并没有促进电力行业资源的有效配置。对于未来的电价改革,在引入阶梯定价的框架下,仍存在较大的改革空间。可以考虑在阶梯定价中嵌入实时定价,据此可以用多元化的手段实现不同的目标。但这一切依赖于利益相关者是否具有改革的动力。     

我国实行交通拥堵费政策的可行性分析

随着我国社会经济的快速发展和城市化进程的加快,城市规模不断扩大,城市人口日益增多,选择小汽车出行的人数越来越多,交通拥堵问题也日渐明显,并逐渐成为部分大城市中的社会问题。文章以外部性理论、公共产品理论和时间价值理论为基础,探讨了我国部分大城市在将来的特定时间和条件下实行交通拥堵费政策的条件和制约因素。笔者认为城市要具备完善发达的公共交通系统、成熟的技术支撑等条件,才能在特定时间和特定路段征收交通拥堵费,以缓解交通拥堵的状况。     

市场化发行方式与我国IPO定价效率的关系研究

利用衡量IPO(Initial Public Offering)定价效率的绝对效率标准,选用1999～2008年沪深市场的IPO数据,研究我国两次新股发行方式的市场化改革与IPO定价效率的关系。结果发现:第一次市场化改革不仅没有提高我国的IPO定价效率,反而降低了IPO定价效率;第二次市场化改革取得了一定的效果,新股询价发行的方向是正确的。     

公路短时车流量预测模型研究

为解决公路交通拥堵,做好道路交通安全规划,应加强对道路交通车流量的实时监控和预测,以便及时发现当前交通的非正常拥堵状况,提高人民的出行效率。公路短时车流量的监测数据具有不确定性和非线性的特点,针对这些特点,运用灰色系统理论预测模型和时间序列的ARIMA预测模型分别对车流量状况进行预测。在此基础上,提出将二者相结合的车流量组合预测模型。通过实例对比分析,得出组合预测模型的预测精度高于单独使用灰色预测模型和时间序列分析模型的结论,该模型可以作为短时车流量预测的一种有效方法。     

Managing Some Motorised Recreational Boating Challenges in South African Estuaries: A Case Study at the Kromme River Estuary

Estuaries in South Africa face negative crowding effects with respect to motorised boat use because of competing demand. This paper proposes this be managed through user charges and that the setting of these charges be informed by applying a choice experiment to estimate user preferences for reduced motorised boat congestion on the Kromme River Estuary, Eastern Cape. The application of this method led the paper to deduce that users are willing to pay an additional supplementary charge of R548 per annum during peak periods (only) in order to experience a decrease in negative crowding effects.     

Impacts of Road Access on Subjective Well‐being in Timor‐Leste

The impacts of access to roads on subjective well‐being at the household level are empirically examined using Timor‐Leste's nationally representative surveys. This paper examines not only the quantity, but also the quality of road infrastructure and, thus, extends existing studies that only consider the benefits of road accessibility. It is found that proximity to main roads may not necessarily result in improved welfare. Instead, ensuring all‐weather access to roads appears to be a more significant factor in raising household well‐being. Specifically, road accessibility during the rainy season reduces the probability of households reporting a ‘less than adequate’ (low satisfaction) response by 13–25 percent. This suggests that in Timor‐Leste, and likely in other developing economies under similar conditions, maintenance of existing roads is more essential to well‐being than building more roads.     

双城构架导向下公路改城市道路的规划策略——以准格尔旗薛大路为例

以双城构架模式下公路改城市道路的规划思路梳理为切入点,以"整体谋划、双城互促、全面融合"为原则,提出基于中小型经济生态圈视角和典型道路功能带视角的公路改城市道路的规划策略,并以准格尔旗薛大路为例,对提出的规划策略进行实例印证.结果表明:改造后的城市道路弥补了原有公路的不足,促进了城市组团间的有效联系;道路横断面改造和道路景观改造成果提升了原有道路的景观性和经济性,为发展道路景观经济带奠定基础.     

Does Aid for Roads Attract Foreign or Domestic Firms? Evidence from Cambodia

Less developed countries have received substantial foreign aid for transport infrastructure, making its quantitative assessment important. To investigate the effect of aid for road infrastructure on the location of foreign and domestic firms, this study employs the first comprehensive census on all business establishments in Cambodia for 2011 and measures the geographical distribution of aid disbursements in roads. Estimating a negative binomial model, we find that aid disbursements in roads have little influence on the entry of foreign and domestic firms across communes. Compared with the aid effect, the location of firms is more strongly influenced by other determinants such as population size, electricity access, and labor supply.     

我国农村土地承包经营权流转存在的问题及对策

文章以现有土地流转方式为分析对象,分析了土地承包经营权流转中存在流转机制不健全,流转秩序混乱,流转的价格不规范等问题。文章指出,缺乏对土地承包经营权流转合理价格的定位和在立法方面政策不完善是造成上述问题的起因。文章最后提出了解决我国农村土地承包经营权流转问题的对策建议。     

试析以信息化促进我国农业产业化发展

传统的工业化道路,是用产业化思路去解决“三农”问题。而新型工业化道路,就是要走出一条“以信息化带动产业化,以产业化促进信息化”的新型农业现代化道路。当前我国农业产业化过程中的信息化建设,需要进行相应的改革和完善。     

Road capacity change and its impact on traffic in congested networks: evidence and implications

This article reviews explanations of, and international empirical evidence for, ‘induced’ traffic as a result of increased road capacity and ‘suppressed’ traffic as a result of decreased road capacity. In essence, the former refers to new traffic appearing as a result of new road construction, while the latter refers to traffic disappearing as a result of road closure. Despite problems with the available data and their measurement, it is concluded that – with the caveats of either pre‐existing congestion in the case of capacity increases or no spare capacity in the case of capacity decreases – the weight of evidence indicates that induced and suppressed traffic are indeed real phenomena. It is argued that the link between traffic and road capacity is therefore far more complex than previously understood. The implications this has for both urban passenger transport planning practice and policy formulation are discussed.     

AN ECONOMIC APPRAISAL OF THE IMPACT OF TRAFFIC DIVERSION – THE N1 TOLL ROAD AND ITS ALTERNATIVE

This paper investigates two alternative roads running parallel to one another; one being a double‐carriageway national road that was tolled 4 years ago and the other being an inter‐city single‐carriageway road. The purpose of the paper is to test the application of the World Bank‐developed Road Economic Decision (RED) model for assessing the economic impact of traffic diversion between two existing alternative roads. In order to do so, the RED model is first used to conduct a cost–benefit analysis of each road in isolation. Thereafter, the model is used to do a scenario analysis followed by a sensitivity analysis. The results show that the RED model is a useful tool for evaluating the impact on society of diverted traffic between alternative roads elsewhere in South Africa.     

基于大美龙江的黑龙江省绿色公路建设思路研究

为推动"大美龙江"建设发展,实现黑龙江省绿色公路建设与公路路域生态环境保护可持续发展,针对黑龙江省区域气候和公路生态环境特征,开展黑龙江省绿色公路的调查研究,总结黑龙江省绿色公路特征,准确把握龙江区域环境与其工程特点,研究总结出黑龙江省绿色公路建设思路,对黑龙江省因地制宜建设绿色公路具有重要指导意义.     

兰州市15分钟社区生活圈划定及步行网络优化

基于生活圈划分的相关标准和要求,划分兰州市中心城区15分钟社区生活圈。从优化步行网络的视角出发,通过ArcGIS网络分析和现场调研,梳理出兰州市中心城区生活圈步行网络现状存在的问题：步行路网密度偏低;部分生活圈内日常服务设施可达性不佳;部分生活圈人行道宽度不足;步行环境不佳。据此提出4个方面的步行网络优化策略：通过新增支路、疏通断头路等手段有效增加步行路网密度及连通性;通过局部建筑环境微改造、功能可兼容服务设施共享等,提高日常服务设施可达性;加强路权管理保障人行步道宽度满足1.5 m;平整道路铺装、优化景观绿化、增设休憩设施、 整顿步行道界面,营造舒适的步行环境。     

上海市交通拥堵成本测算及对策研究

依据美国德克萨斯运输学院交通拥挤外部成本的经典测算模型，将交通运输拥挤成本分为时间延误成本、额外燃油消耗成本、环境污染物排放成本和噪音成本三个方面，对于2015年上海市工作日高峰期交通拥挤的外部成本进行了详细的测算。结果表明，交通拥堵的外部成本约占当年上海市GDP的0.63%。最后，对于交通拥堵成本较高的现状提出了包括对上海市部分高度拥堵路段或区域收取拥堵费、大力发展上海市公共交通和发展交通快慢型出行方式共存在内的相关政策和建议。     

退耕还林政策效果分析——基于内蒙古赤峰市的调查

文章以内蒙古赤峰市为例，以来自部分农户的调查数据和统计年鉴等资料为基础，采用实证分析方法，对该地区退耕还林政策效果进行分析。结果表明，该政策对改善生态环境、调整农业产业结构、提高粮食单产、增加农民收入等产生了积极影响，但也存在林权纠纷、配套政策不完善、剩余劳动力增加、后续产业发展滞后等一些问题。据此，文章最后相应提出一些完善该政策的建议。     

绿色城市社区内部交通系统规划策略研究

近年来,随着我国城镇建设速度的持续加快,在城市建设的过程中,产生了一些不可避免的问题,其中道路交通问题尤为突出。与此同时,关于绿色城市社区的研究越来越深入,运用这一模式来解决城市问题已经得到越来越广泛的认可。本文试图在绿色城市社区的发展模式下定性分析各种类型的道路、路网以及道路空间,通过对绿色城市社区内部交通系统的概念、分类、影响因素和道路网络形态的分析,探讨一种可持续发展的交通模式,从而建立一套完备的城市交通系统,以最佳的方式为城市服务。