This paper on catchment areas used for public transport is from the proceedings of 14th International Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors explain that, in the planning of public transport, the catchment areas of stops are often included to estimate the potential number of travelers. They describe different approaches to GIS-based catchment area analyses, including the Circular Buffer approach which is the fundamental, but also the simplest approach; the Service Area approach, which is based on searches in road networks, represents the actual feeder routes, and is a more detailed approach; and the Service Area approach, which can be refined by adding additional resistance to certain points in the road network, e.g. stairways. The authors illustrate differences between the Circular Buffer approach and the Service Area approach and compare the sizes of the resulting catchment areas. One case example illustrates the strength of the Service Area approach and the impact on the catchment area when adding additional time resistance for the crossing of stairways. Another case example illustrates how the additional time resistance in stairways affects the catchment area of an underground station compared to a ground-level station. The benefits of catchment area analyses include improved planning of stops on a new line by calculating travel potential along the line; the prevention of inaccessible areas from being included in the catchment area; and the allowance of detours in feeder routes to/from stations. The authors conclude that GIS-based catchment area analyses are a beneficial multiple decision support tool for the planning of public transport where the level of detail can be suited to the purpose.