TransMilenio BRT system in Bogota,high performance and positive impact – Main results of an ex-post evaluation

The paper presents the main characteristics, costs and impacts of TransMilenio, the bus based mass transit system of Bogotá, using BRT corridors and feeder services. An ex-post cost-benefit analysis is done, including monetary valuation of direct impacts on travel time and travel cost and externalities, such as improved road safety and air quality. Impacts on crime, land values, employment and tax revenue are also presented. The results are positive and robust; nevertheless, it is important to recognize that user perception has declined and there is urgent need to introduce service improvements. The paper also includes an ex-ante evaluation of the projected expansion using current costs, which indicates the need to limit construction capital costs. The results are an indication of the potential of BRT, and the evaluation methodology is applicable to other transit projects.     

Indicators for Evaluating the Impact of Artificial Islands on the Barcelona Coast

Artificial islands have been constructed next to large cities due to the need for extra space in highly populated areas. These emerged structures have been used by many countries as platforms for developing infrastructure (airports, harbors, highways, etc.), rebuilding ecological areas, and creating new spaces for tourism or residential areas. In this study, two state-of-the-art numerical models for wave propagation and nearshore circulation are used to simulate the effects of an emerged artificial island on the Barcelona coast. Several sea indicators (wave height, intensity and direction of currents, and mean water level) are analyzed to assess the changes likely to be induced by an artificial island. Three different situations are studied and the indicators are compared across the different tests to obtain information that can be used in the planning process of these structures. In two-meter wave conditions, the tests show that wave height is generally reduced in the sheltered area, which leads to improved safety for beach users (bathing is prohibited when wave height exceeds the two-meter threshold). However, the numerical models also reveal that velocities in the sheltered area usually decrease, which must be controlled to prevent stagnation in the bathing area.     

Quality indicators and capacity calculation for RoRo terminals

Abstract

Road freight transportation has increased dramatically over recent years along with its impacts such as congestion, noise, and pollution. As a result, European and US governments have started policies to promote alternatives to road transportation, such as logistic chains containing a Short Sea Shipping (SSS) link. Road is, by definition, a more flexible means of transportation than shipping, which is usually cheaper. Therefore, to move traffic to SSS chains, it is necessary to provide fast, frequent, and reliable maritime transportation. In this sense, roll-on/roll-off (RoRo) vessels are the most convenient ships to be used, since they have smaller dwell times in port and, therefore, this is a kind of traffic likely to increase dramatically. The foreseeable increase of this kind of traffic must meet with an increase in the actual capacity by means of either improvement in performance and possible enlargements of existing terminals or the construction of new terminals. In that sense, this paper proposes a simple methodology to calculate the capacity of a RoRo terminal, whether already in operation or during its design process, and relate it to some quality standards by means of quality indicators, which should lead to the definition of Levels of Service similar to those already used in roads and airports. The paper ends by applying the methodology to a real terminal in Barcelona, Spain.     

小城镇交通系统特征分析及其在公共交通规划中的应用研究

在众多小城镇分类标准中,对小城镇的概念及定义做了明确界定,分析了小城镇的几个重要特征,即社会经济水平、土地利用特征、居民出行特征、公交需求特征和供给特征。采集了一些典型小城镇的交通特征指标,并就这些特征指标值和大中城市做了相应对比,明确了小城镇概念及其交通系统特性。重点关注目前我国小城镇公交发展的实际情况,结合小城镇公交运行的实际情况,给出小城镇公交线网规划指标的推荐数值。      

基于AHP和模糊熵的高速公路隧道重要度评价

在高速公路管理中,如何针对不同类型、不同区域、不同建设规模等数量繁多的隧道制定针对性、差别化的管理方案是管理部门的难题之一。本文通过参考国内外已有的研究成果,开展对高速公路隧道重要度影响因素的深入分析,提出六个重要度评价指标:隧道土建结构,隧道长度,隧道路面状况,隧道交通量,绕行距离,雨、雾、冰雪天气,并通过采用AHP方法与模糊熵法确定各指标权重,建立了完整的隧道重要度评价方法,使隧道管理部门能够根据高速公路中隧道重要度的差异,制定相应的管理方案。     

高速公路路面质量指标的敏感性分析

通过建立主要成分分析模型,研究影响高速公路路面质量指标的因素。文中结合大量试验数据,对比分析了10种影响因数的敏感性。结果表明:可以用油石比、筛孔通过率、空隙率三个参数代表10个影响因素来表述其对路面性能的影响。提出的分析模型和运用的基本数学理论,可为实际中评价路面质量提供科学依据。     

既有桥梁改造方案经济分析模型的构建

在确定既有桥梁各种改造方案的基础上,从工程经济的原理出发,在桥梁全寿命期内,考虑所有可能发生的费用,建立桥梁的全寿命周期费用模型(平均年费用模型),并且对加固、重建方案的平均年费用进行相互比较、分析。同时还基于平均年费用的分析模式,对桥梁的经济使用寿命进行了预测。     

体积指标测试进展及其对沥青混合料性能影响分析

沥青混合料的空隙率、矿料间隙率、沥青饱和度是沥青混合料的三大体积指标,它们直接影响到沥青混合料的使用性能。通过文献综述和工程实践数据论述了沥青混合料体积指标的测试进展及其对沥青混合料使用性能的影响,并通过对广东省某高速公路Superpave混合料的设计,分析了体积指标内在的关系及影响因素。     

基于态度-行为模型的低收入通勤者出行方式选择

为了分析城市低收入通勤者交通方式选择行为,揭示个体社会经济属性、活动 属性和潜在态度变量对出行者出行方式选择的影响,基于抚顺市居民一日出行调查数 据,采用态度-行为模型探究低收入通勤者出行方式选择机理.首先基于多指标多原因模 型分析影响态度变量的外在因素,结果表明性别、驾照拥有情况和年龄对态度变量的构 成影响较大.然后,分别建立含潜变量和不含潜变量的多项Logit 模型,发现含潜变量的选 择模型更能解释出行行为,社会经济属性、活动属性和态度变量对低收入通勤者出行方 式选择影响存在一定差异.     

技术指标在设计中的灵活运用

讨论了道路设计中诸多制约因素的互相影响,通过分析,预测道路的近、远期交通量以及在区域控制网中的地位,合理确定道路的线形技术指标和经济指标,并阐述了这些指标在设计中的灵活运用。