Biking and walking are rather neglected transport modes within transportation research. In terms of their contribution to the total number of kilometers travelled, their share is indeed small in most countries. However, their share in the total number of trips made is substantial almost everywhere. For quality of life in cities, a substantial share of the non-motorised transport modes appears to be an unavoidable and essential element. Every trip contains non-motorised elements (for example, walking from the parking place to the final destination, biking to the railway station, etc.). The contribution of non-motorised transport modes to the urban quality of life is gaining increasing attention at the level of national and local governments in many countries (Tolley, 1997; Dutch Ministry of Transport, 1999; Pucher et al., 1999; Organisation for Economic Co-operation and Development, 2000). Among the factors that may stimulate non-motorised transport modes in the future are: (1) Improved image: health considerations are becoming more and more important in consumer behaviour and even limited use of non-motorised transport modes appears to reduce the risk of heart problems (Hendriksen, 1996). Health considerations were mentioned as the major reason for) participation in a bicycle use program in Denmark (Lahrmann and Lohmann-Hansen 1998); (2) Introduction of new types of bicycles (for example, the mountain bike led to an improved popularity of biking among youngsters); and (3) Consistent government policies to remove barriers against non-motorised transport modes, for example traffic calming. Thus, there seems to be a potential for substitution of trips from motorised ones towards non-motorised ones. It appears indeed that in the range of trips of distances up to about 7 km where non-motorised modes are potentially attractive, there is substantial room for substitution. However, a closer examination of the data yields several indications that substitution between non-motorised transport modes and public transport is stronger than between non-motorised transport modes and the car. Thus, stimulation of non-motorised transport does not necessarily lead to less car use in cities.
Abstract