Trrl Lr 918

The report describes a theoretical study of the likely effects of installing a contraflow bus lane in a one-way street system. The study, which is concerned only with the time and money components of a cost/benefit comparison, consisted of three distinc parts: the first was the formulation of a general economic framework in which benefits to buses and their passengers arising from the provision of a contraflow lane in a street network were compared with the disbenefits to other traffic as a result of the presence of the lane and the costs of operating and implementing the scheme; from the results general warrants were derived. The second part was a detailed theoretical study of a number of hypothetical situations representing four different road configurations with junctions controlled by signals, roundabouts or channelisation systems. A detailed examination of the changes in junction capacity and vehicular delays highlighted the problems which can arise ehen junctions, previously simplified on installation of one-way traffic regulations, have some of the complexities reintroduced in order to accomodate the reserved lane. The case studies indicated the sensitivity of the warrants to the type of junction control in use and suggested that, in practice, for most situations it would be necessary to carry out a specific economic assessment. The third part of the study was therefore the formulation of a standardised assessment methodology for calculating the appropriate warrants and the economic benefits for any given scheme.