A host of centralised and decentralised systems are available for wastewater disposal purposes. Consequently, selecting the right system calls for a comprehensive and, above all, unbiased assessment of the alternatives. Costs and unsettled ecological issues can be adduced to show that total rejection of one system or the other is not warranted. An ecological assessment that, for example, also covers hygienic aspects is only in its infancy and an intensification of research work is necessary. The example of a conurbation is used to illustrate the interplay of centralised and decentralised elements.
The public transport network level is defined and is used to describe the performance and future improvement of the public transport system in Zurich, Switzerland. A public transport level is a specific type of service designed to serve a particular market. “Service” is defined as a combination of vehicles, infrastructure, and operating characteristics. A pure level occurs when the service is targeted specifically at one particular market. A hybrid level occurs when a service is targeted to serve several markets. Urban travel is generally described as three markets: short, inter mediate, and long-distance trips. Consequently many cities have developed three-level public transport networks: surface buses and trams to serve short trips, rapid rail to serve intermediate trips, and regional rail to serve longer-distance trips. Often, by design or for historic reasons, cities have additional levels, fewer levels, levels that are not precisely matched to their markets, or all three. For example, two-level networks are often found in medium-sized cities. Their advantage is lower costs, and their main disadvantage is a mismatch between transport mode and market that manifests itself in capacity limitations. The level concept to help analyze and plan public transport service is useful because it focuses attention on matching service qualities to markets. This approach, used here to analyze the success of the public transport system of Zurich, Switzerland, and to provide a structure for planning improvements that will be needed to meet rapidly increasing public transport demand, could help other cities design or redesign their public transport systems to be more attractive and efficient. More specifically, the approach could show how two-level public transport networks would be a viable option for medium-sized cities and large cities with dispersed settlement patterns.
Accurate measurement systems of performance are important for all businesses, including public transport. The importance of such systems will grow with the advent of liberalization in the European transportation sector (i.e., the opening of transit service provision for tendering), as service provision contracts will require agreed-on measures for performance and service. This paper describes research on developing a public transport level-of-service (LOS) standards framework for Switzerland. The standards framework is intended to reflect influences on capacity and operational quality in urban road-based transit and relies on four main measures: speeds, passenger loads, on-time performance, and headway adherence. This paper outlines the selection of specific measures for evaluating public transport LOS and the proposed framework. The framework provides a consistent method for evaluating public transport LOS on all levels of analysis, from single elements (e.g., bus stops) to networkwide analysis. The paper also describes how information from automated onboard data collection systems can be used for detailed service analysis. This calibration procedure is illustrated in an example from the Zurich public transport system. Challenges faced (especially with respect to the selection and filtering of relevant data) and future development of the approach are described. While the proposed LOS framework is being prepared for Switzerland, the experience and approach described should help others developing and improving performance management systems for public transport.
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