BRT and BHLS around the world: Explosive growth,large positive impacts and many issues outstanding

A survey of Bus Rapid Transit BRT and Bus of High Level of Service BHLS around the world indicates that there are about 120 cities with bus corridors, with 99 of the cities entering into the list in the last 12 years. The existing bus corridors comprise about 280 corridors, 4300 km, 6700 stations and use 30,000 buses, serving about 28 million passengers per day. In 2010–2011, 19 cities completed new systems − 16 in the developing world – and seven cities expanded their current systems. By late 2011, about 49 new cities were building systems, 16 cities were expanding their corridors, and 31 cities were in initial planning. This impressive growth may be attributed in part to the successes of Curitiba, Bogotá, México City, Istanbul, Ahmedabad and Guangzhou. These cities show low cost, rapid implementation and high performance BRTs, with significant positive externalities. Interesting trends are emerging, such as the implementation of citywide integrated bus systems, improved processes for private participation in operations, increased funding from national governments, and growth of bus manufacturers and technology providers. Despite the growth, there are some outstanding issues: BRT and BHLS do not have a single meaning and image and are often regarded as a “second best” as compared to rail alternatives. In addition several systems in the developing world suffer problems resulting from poor planning, implementation and operation, due to financial, institutional and regulatory constraints. The BRT and BHLS Industry are in their “infancy” and there is need for consolidation and concerted effort.     

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.     

A first glimpse on policy packaging for implementation of BRT projects

Policy packaging (i.e. the combination of individual policies and measures in order to achieve a certain goal) is a common practice in urban mobility management used to create synergies between single policies or to mitigate negative effects of a given policy.     

Valuing casualty risk reductions from estimated baseline risk

Stated choice studies have been applied regularly to the valuation of time savings and other attributes of travelling as perceived by individuals. In such experiments, respondents often provide reference levels for the attributes and the hypothetical choices presented to them are pivoted around actual behaviour. However, most individuals are not able to provide reference levels for the number of casualties on the road they travel. Thus, if valuation of this important element is attempted, it is the researcher who must provide casualty risk reference levels to the respondents. Some studies have applied route choice experiments including a safety attribute but the majority has been limited to only one particular road section with a common baseline risk for all respondents.     

建成环境对步行和自行车出行的影响--以波哥大为例

哥伦比亚波哥大以可持续的城市交通系统闻名,包括其密集的自行车道网络以及Ciclovía系统——为骑车者和行人预留的道路空间,可在星期日和节假日休闲出行使用。探讨此类设施以及建成环境的其他属性——城市密度、混合用地、可达性以及与公共交通车站的距离——如何影响步行和自行车出行行为以及Ciclovía的使用。结果表明,道路设施设计要素例如道路密度、连通性、与Ciclovía车道的距离,与体力活动相关;而建成环境的其他属性如密度和用地混合程度,对体力活动影响甚微。这可能是由于波哥大建成区的大部分街区均在非机动交通出行占绝对优势的时期演变发展——紧凑、用地混合、交通可达性水平相似。由此可见,影响非机动交通出行的因素是设施设计而非一般的街区用地属性。     

Railway Vehicle Modelling by the Constraint Equation Method*

A method for the dynamic analysis of railway vehicles is proposed. The method is based on both the using of constraint equations, and on the building of the mathematical model by means of the initial data.

The calculation models are nonlinear, due both to the connecting elements, and to the wheel-rail contact modelling. Solving of differential equations is achieved by time step integration. The method has been applied to the analysis of a freight wagon and a train unit.     

Topological analysis of powertrains for refuse-collecting vehicles based on real routes–Part II: Hybrid electric powertrain

In this two-part paper, a topological analysis of powertrains for refuse-collecting vehicles (RCVs) based on simulation of different architectures (internal combustion engine, hybrid electric, and hybrid hydraulic) on real routes is proposed. In this second part, three different hybrid electric powertrain architectures are proposed and modeled. These architectures are based on the use of fuel cells, ultracapacitors, and batteries. A calculation engine, which is specifically designed to estimate energy consumption, respecting the original performance as the original internal combustion engine (ICE), is presented and used for simulations and component sizing. Finally, the overall performance of the different architectures (hybrid hydraulic, taken from the first paper part, and hybrid electric, estimated in this second part) and control strategies are summarized in a fuel and energy consumption table. Based on this table, an analysis of the different architecture performance results is carried out. From this analysis, a technological evolution of these vehicles in the medium- and long terms is proposed.     

Transition between Signal Timing Plans: A Methodological and Analytical Overview

Abstract

The transition phase is generally defined as the process of switching from one timing plan to another; this process may include changes in offset, phase split or cycle length until coordination for a new timing plan is reached once again. As noted in the literature, transition phases between timing plans may lead to severe disruptions of traffic flow, resulting in potentially lasting effects. The aim of this paper is to comprehensively review, classify and analyse the literature regarding transition between different timing plans to highlight existing research gaps and give researchers a starting point to continue contributing with solutions to the transition problem. Regarding transition approaches, a gap concerning mathematical approaches was deemed significant as a transition could be greatly benefited by simultaneously optimising more than one operational measure of effectiveness through multi-objective mathematical models. Moreover, in the analysis of applied approaches, Shortway algorithms generally outperformed other practical methods under different scenarios.     

Comparative analysis between operational weather prediction models and QuikSCAT wind data near the Galician coast

Wind measurements from SeaWinds scatterometer on the NASA QuikSCAT satellite and wind forecasts from two different operational numerical models provided by MeteoGalicia were compared for a 4-year period (2002–2005) in Galician coast environment. Available wind data buoy measurements were also used to complement the analysis. A statistical analysis based on mean errors, root mean square errors and complex correlation was performed from spatial, temporal and directional points of view.In the spatial comparison no significant differences between models and satellite were observed and the error magnitudes of the models are compatible with typical QuikSCAT errors. The suitability of satellite wind estimations for data assimilation in these models must be further investigated. Negative bias of models with respect to the satellite was also confirmed with buoy data, in such a way that models overestimation is smaller than the satellite one. Big errors in wind direction appear in southeasterly and southwesterly winds for both satellite and models, contributing to high RMSE values when compared to buoy data. These errors were mainly attributed to the effect of insufficient spatial resolution near shore.