This literature review raises four key points of particular relevance to the objectives of
this research. First, smart card penetration is critical to its effective use for the analysis of
passenger behavior. This point supports Oyster-based research in London where 73 percent of
all journeys on the TfL network were made by Oyster card in 2007 (Mayor of London 2007).
Moreover, the value of analyzing passenger behavior using smart card data should be
considered relative to existing survey-based data systems. Second, a range of interchange time
assumptions between 30-90 minutes has been used in previous studies for linking bus journey
stages to form complete journeys depending on the location and purpose of the study. Third,
previous studies provide examples of the development of bus origin-destination matrices using
a combination of data from smart cards and other sources, especially APC and AVL systems.
Given the ongoing deployment of Tfl's AVL system, iBus, these complementary data sources
need to be considered in the next stage of smart card research and analysis for bus network
planning in London. Finally, interchange planning has long been recognized as a key
component of public transportation planning but has recently enjoyed renewed interest under
the policy framework of developing more integrated and intermodal networks. Oyster smart
card data is of particular value in capturing individual travel on multiple modes so, in
combination with a strong interest in interchange planning in the United Kingdom and at TfL,
supports the emphasis of this research on bus passenger interchange behavior.