The London Bus Priority Initiative started in 1990, and the first studies for the demonstration project have indicated that the economic benefits which can be attributed to improved regularity and reliability of bus operations can be considerable. However, the divergence of methods used in these first studies has made clear that if the regularity and reliability benefits are to be integrated into the economic evaluation of public transport improvements and "package" proposals, a more systematic approach to "capturing" these benefits would be necessary. This paper describes a methodology devised and used in the Hackney and Haringey bus priority study (A10 and A503-A105-A1080 corridors) for London Transport. London Transport. The overall approach requires bus routes/corridors to be divided into individual links as described in the Bot's "Keeping buses moving" guide. Estimates of service regularity benefits are based on the direct modelling of "excess waiting time" at bus stops. Reliability benefits are quantified as passenger "allowance time" savings prompted by changes in the expected bus journey time. The two prediction equations developed for the methodology are expressed in terms of easily obtainable variables and could explain between 68% and 83% of data variability along the study corridors. It was found that regularity benefits along the two NE London corridors were primarily determined by bus journey times and speeds while reliability benefits were also affected by the traffic volume to capacity ratio (V/C). Regularity and reliability benefits together were found to make up about 20% of the total bus-related person time savings. (A)
Samenvatting