Paratransit systems are either well established or expanding in both developed and developing countries. They are characterised by continuous spatial and temporal variations of routing, stopping and scheduling patterns in response to changes in demand. Their flexibility necessitate analytical techniques different from those commonly used for formal transport systems. Geographical Information Systems (GIS) are increasingly used in the modelling of systems which have an explicit spatial dimension. Data representation in GIS makes it possible to represent and analyse most transport problems. Points, lines and polygons, the fundamental data types in GIS, can represent most transport phenomena and especially problems which have a direct need for spatial referencing such as paratransit. Transport services are a dynamic environment making it imperative that GIS at least have a temporal dimension which has, however, not been easy to implement. Further, GIS also have weaknesses with respect to specialised transport related problems. On the other hand, transport has a well developed core of techniques for most such problems. This paper is based on a study investigating the implications of adopting various operational configurations on paratransit operators and users. A simulation model built through dynamic linkage of a GIS to specialised computer models is discussed. The GIS analyses, extracts and displays the key spatial data which influence paratransit operations. The simulation model adds the temporal dimension and incorporates several modules on the movement of vehicles and their interaction with users. One of the aims of the research has been to investigate the possibilities for interfacing GIS to other computer programs in a dynamic environment. Preliminary results of the study are presented.
Abstract