Alternative financing for Bus Rapid Transit (BRT): The case of Porto Alegre, Brazil

In the 1970s, Brazil was leading the implementation of high-flow bus priority schemes, but now cities are less capable of financing public infrastructures. This paper explores the private sector participation in the provision of transit infrastructure based on Public-Private Partnerships (PPP) for Bus Rapid Transit (BRT). The Porto Alegre BRT contemplates interchange terminals planned to accommodate retail and service activities. It is expected that these areas shall generate enough revenues to remunerate private investors, under a PPP scheme, for the construction of terminals and part of the infrastructure required to upgrade some sections of the existing busways to BRT standards.     

Formulating and solving the network design problem by decomposition

The optimal transportation network design problem is formulated as a convex nonlinear programming problem and a solution method based on standard traffic assignment algorithms is presented. The technique can deal with network improvements which introduce new links, which increase the capacity of existing links, or which decrease the free-flow (uncongested) travel time on existing links (with or without simultaneously increasing link capacity). Preliminary computational experience with the method demonstrates that it is capable of solving very large problems with reasonable amounts of computer time.     

Preface and Acknowledgments

Abstract

The term “mitigation”; has been used in connection with habitat losses attributable to federal water projects as early as the Rivers and Harbors Act of 1899 and the Fish and Wildlife Coordination Act of 1934. Most of the current requirements to mitigate habitat losses associated with water development projects apply to wetlands, as they are biologically productive and have been destroyed at an increasing rate during recent years by developers seeking prime land in the coastal zone. A case study of the Port of Coos Bay and the City of North Bend, Oregon, provides an actual experience of estuarine mitigation in a dredging project and an airport fill. The case was developed as part of a larger curriculum research study for seaport management. This article is primarily written as a case with a brief introduction and discussion of mitigation requirements, followed by the text of the case and ending with a series of hypotheses for further research.     

On appropriate microstate descriptions in entropy modelling

Using an information-theoretic approach to entropy modelling, expressions for the possible number of microstates are derived from the sets of choices available to households and firms in given location/transport planning situations. In planning applications, the urban space is usually subdivided into discrete zones, and various classes of householders and firms are grouped into separate activities. Nevertheless, the location sites within zones may vary considerably in accessibility, price and quality, and amenity v. cost trade-offs between location and travel many differ markedly between individuals within the same activity group. The inclusion of such variations within a random utility framework is demonstrated to be equivalent to maximizing entropy with the microstates disaggregated to the level where these variations occur. Using constraints based on spatial conditions, observed behaviour and planning policy, entropy maximization is used to determine the most probable macrostate according to each choice set specification. The resulting distributions are compared and their revelance discussed.     

Book review

AUTOMATED‐TRANSIT GUIDEWAYS: ANALYSIS AND DESIGN, by Clarence W. de Silva and David N. Wormley. 276 pp. (£33.00)     

Democratization of Coastal Zone Decision Making for Indigenous Australians: Insights from Stakeholder Analysis

Community participation has become something of an orthodoxy within natural resource management. In the absence of an explicit strategy for democratization and capacity-building the notion of community participation is potentially meaningless and its application likely to mask decisions made in the interests of elite groups. This article examines the shortcomings of participatory processes in coastal resource management and seeks to identify and overcome constraints to democratization and capacity-building for Indigenous Australians. Using two coastal catchments in Central Queensland as a case study, we explore relations of power among stakeholders using Stakeholder Analysis to provide a platform for more effective deliberative participation by this group of stakeholders. Discussion of the specific barriers to participation identified by Aboriginal stakeholders will demonstrate the need to adopt notions of capacity-building that focus not only on the attributes of the individual stakeholder that might facilitate their participation, but on the characteristics also of the decision-making environment.     

Design and implementation of efficient transit networks: Procedure, case study and validity test

This paper presents and tests a method to design high-performance transit networks. The method produces conceptual plans for geometric idealizations of a particular city that are later adapted to the real conditions. These conceptual plans are generalizations of the hybrid network concept proposed in Daganzo (2010). The best plan for a specific application is chosen via optimization. The objective function is composed of analytic formulae for a concept’s agency cost and user level of service. These formulae include as parameters key demand-side attributes of the city, assumed to be rectangular, and supply-side attributes of the transit technology. They also include as decision variables the system’s line and stop spacings, the degree to which it focuses passenger trips on the city center, and the service headway. These decision variables are sufficient to define an idealized geometric layout of the system and an operating plan. This layout-operating plan is then used as a design target when developing the real, detailed master plan. Ultimately, the latter is simulated to obtain more accurate cost and level of service estimates.This process has been applied to design a high performance bus (HPB) network for Barcelona (Spain). The idealized solution for Barcelona includes 182 km of one-way infrastructure, uses 250 vehicles and costs 42,489 €/h to build and run. These figures only amount to about one third of the agency resources and cost currently used to provide bus service. A detailed design that resembles this target and conforms to the peculiarities of the city is also presented and simulated. The agency cost and user level of service metrics of the simulated system differ from those of the idealized model by less than 10%. Although the designed and simulated HPB systems provide sub-optimal spatial coverage because Barcelona lacks suitable streets, the level of service is good. Simulations suggest that if the proposed system was implemented side-by-side with the current one, it would capture most of the demand.     

Hybrid vehicle power management modeling and refinement

The power management strategy in many hybrid vehicles is based on expert rules and thresholds. These rule-based strategies can result in good efficiency in term of fuel economy and emissions if their thresholds and rules are accurate. However, due to the complexity and the non-linearity of the hybrid powertrain, determining accurate thresholds and rules is neither explicit nor straightforward, and experts in most cases fail to define these thresholds and rules with enough accuracy. Based on this fact, the objective of this paper is to propose a method to improve this rule-based strategy by refining its thresholds and rules. To achieve this, we used an optimization method (dynamic programming) to calculate the optimal power management, determine the optimal control signals, and extract efficient thresholds and rules that can be used in real time. Finally, simulation results for the three strategies (optimal, simple and refined strategy) are shown and discussed.     

Nonlinear tire-road friction control based on tire model parameter identification

A hierarchical control structure is a more suitable structural scheme for integrated chassis control. Generally, this type of structure has two main functions. The upper layer manages global control and force allocation, while the bottom layer allocates realized forces with 4 independent local tire controllers. The way to properly allocate these target forces poses a difficult task for the bottom layer. There are two key problems that require attention: obtaining the nonlinear time-varying coefficient of friction between the tire and different road surfaces and accurately tracking the desired forces from the upper layer. This paper mainly focuses on longitudinal tire-road friction allocation and control strategies that are based on the antilock braking system (ABS). Although it is difficult to precisely measure longitudinal tire-road friction forces for frequently changing road surface conditions, they can be estimated with a real-time measurement of brake force and angular acceleration at the wheels. The Magic Formula model is proposed as the reference model, and its key parameters are identified online using a constrained hybrid genetic algorithm to describe the evolution of tire-road friction with respect to the wheel slip. The desired wheel slip, with respect to the reference tire-road friction force from the top layer, is estimated with the inverse quadratic interpolation method. The tire-road friction controller of the extended anti-lock braking system (Ext-ABS) is designed through use of the nonlinear sliding mode control method. Simulation results indicate that acceptable modifications to changes in road surface conditions and adequate stability can be expected from the proposed control strategy.     

SCR control strategy based on ANNs and Fuzzy PID in a heavy-duty diesel engine

The paper presents an innovative method combining artificial neural networks (ANNs) with Fuzzy PID to demonstrate the advantages of this control approach for meeting both NOx emission requirements and NH3 slip targets. An ANN model was utilized to simulate the formation of NOx emissions under various engine operating conditions. Next, an effective closed-loop control strategy with a type of feedback known as fuzzy PID is adopted for on-line, real-time control of 32.5% aqueous urea dosing in the exhaust stream. The new strategy explores the benefits by simulation and testing in the environments of Matlab/Simulink and ESC/ETC, respectively. The notable achievement of considerable NOx reduction and an acceptably small NH3 slip is obtained based on this new, feasible and effective strategy.