The GCOST™ model
The Railway Consultancy Ltd has developed the GCOST™ model, which is a time-efficient and cost-effective way of analysing options for new stations and services.
The GCOST™ model is a spreadsheet-based model constructed as a series of worksheets. Each of the first five comprises details of an element of the journey, for a range of pairs of key traffic origins (Os) and destinations (Ds). The data is collected separately for peak and offpeak conditions, and for the main modes involved e.g. car, bus, train, park and ride. Journey elements which may be appropriate include access (e.g. walking to the station), waiting, in-vehicle time, the number of interchanges, and public transport fares and car parking charges. The sixth sheet calculates the generalised cost for each O:D pair.
The seventh sheet can be adapted to the circumstances, but contains some global information about trips (for instance, population estimates or Journey-to-Work data. Critically, however, the main part of this sheet comprises a logit model, which allocates traffic between the various modes. It is calibrated to reproduce existing data - a small-scale survey may be needed here, in order to ensure that the model is working correctly. Once calibrated, however, the model can be used to forecast new situations, by varying the input data to reflect options for the future - perhaps faster services, or a new station. The number of trips on the proposed service is a key output.
Other outputs, however, are also easily derived. With information already known on both fares, and the number of trips, by Origin:Destination pair, revenue can also readily be calculated. With the number of trips and total time known, time savings between options are also easily derived - and this can form the basis of a preliminary Cost:Benefit Analysis (for a section 56 or other Government grant).
Last updated: Sunday, 18th December 2016
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