Dr Thornbush has been studying urban sustainability since her doctoral research at the University of Oxford, where she investigated the impact that reduced traffic stemming from the Oxford Transport Strategy (OTS) had on the city's historical buildings in central Oxford, UK. She has published on this topic and expanded the reach to sustainable cities and, more recently, to the energy-smart cities of the future. Her approach remains one of integrated, interdisciplinary approaches that crosscut traditional disciplinary boundaries at broad spatial-temporal scales.