posted on 2009-11-01, 00:00authored byLester B. Lave
Transportation demand models tend to be fragile and limited. They are developed for specific purposes and are unreliable when used more generally. In particular, past models have been deficient in not explaining passenger demand in terms of the attributes of the modes. This means that there is no way to forecast the effect of changes such as increased speed or safety on passenger demand. Furthermore, these models are invariably mode specific and consequently provide no way of looking at total travel when one mode is changed significantly or a new mode introduced. Some recent attempts have been made to develop more general models (Quandt [9]). While these attempts are salutary, much work remains to be done.