In order to address the needs of TfL, MIT will conduct a two-phase research plan to investigate the causes of traffic speed reductions and delays in London. The first phase will involve assembling data from multiple sources, processing the available data, performing initial econometric and traffic behavior analysis using the integrated data and indentifying future data requirements and research directions. The second phase will include: extension of the econometric analysis, development of detailed driving behavior models and microscopic traffic simulation studies for selected sub-networks.