The Transport sector climate action co-benefits evaluation tool, or TRACE, is an Excel-based model to support quantitative evaluation of selected non-climate impacts from decarbonising the urban transport sector. For the most part decarbonisation trajectories for urban transport settings also help deliver positive impacts on sustainable development objectives and therefore represent co-benefits of climate action. Understanding the drivers of these co-benefits and their potential magnitude can help build the economic and social case for transitioning urban transport systems. The first draft of the model facilitates an assessment of impacts on congestion, road accidents, fuel use and can (soon) link to a tool to derive health impacts from air pollution. Impacts are estimated in units such as travel delay, fatalities, and volume or weight of fuel types, as well as monetised, to allow an aggregation of the different impacts. Scenarios for the development of urban transport systems over time are a critical input to TRACE and are not generated within the tool itself.