This case study sets a founding example for cities on how to move from a top-down to a bottom-up transport emissions calculation approach, using Google‘s EIE data as a basis. EIE is a tool utilising various data sources and modelling capabilities to assist cities in assessing emissions sources, conducting analyses, and formulating strategies for impactful actions. Athens has used the tool to obtain more accurate data on the distance travelled by private transport in the city, and based on this, correct their yearly emissions inventories from 2014 to 2022.