Travel behaviour modification, also called TravelSmart®, Indimark® and Travel Blending®, has been offered as a solution to the dependence of urban populations on the car. Travel behaviour modification is a voluntary programme aimed at changing travel behaviour through providing better information about transport options, rather than through investments in public transport, or through disincentive programmes for the car. The policy has been implemented in Australia in Perth, Adelaide, and Brisbane, and is under active consideration at least in Melbourne and Sydney. The basis of this increasingly widespread potential application of travel behaviour modification is the claim that the program can deliver a shift of travel mode choices through the provision of better information about travel behaviour and travel choices. The claims that are made for this programme are that it can lead to reductions in car use of the order of 10 to 14 percent. If these claims are real, then travel behaviour modification is an enormously valuable programme, with the potential to achieve what has never been done before, i.e. provide a doubling or more of public transport ridership and a significant drop in car use. Such a program would be the answer to the dilemma of how to reduce car use significantly and consequently reduce congestion and vehicular emissions. It is, therefore, appropriate to undertake a critical appraisal to determine if travel behaviour modification is able to deliver these major mode shifts, as its proponents claim. In this paper, we review a number of published articles, primarily based on the Australian experience with travel behaviour modification, and also review several reports, and materials from the application areas. From these reviews, analyses are performed to see what the actual expected shift is in mode use for the whole population. It is found that there appears to be evidence that the claims of 10 or more percent shift out of car driver are over-stated, and that real shifts may be of the order of six to seven percent. Second, some sampling issues are discussed that indicate that the numbers reported to date may not be as reliable as one would like. Third, the locations of the test applications are examined and discussed, and it is suggested that there may be some significant bias in these locations towards a larger uptake of the shifts into environmentally-friendly modes of travel. In sum, the paper concludes that travel behaviour modification is capable of making changes in the use of environmentally-friendly modes, but not at the rates that have often been claimed. It is suggested that the target populations may need to be limited and that expectations of the size of the shifts in mode use need to be tempered
