Global warming is one of the gravest concerns that the world is now dealing with. This phenomenon is caused by a variety of factors. Carbon dioxide emitted from transportation networks is a significant contributor to global warming. Transportation systems comprise both the urban mobility sector (including public transportation and private vehicles) and the road transportation system. In line with this issue, governments across the globe have been implementing new technologies and strategies to mitigate carbon dioxide emissions. Meanwhile, changing passengers’ mobility behaviors through the application of nudging techniques has recently been identified as a feasible option by them. This research seeks to improve the efficiency of nudging approaches used in the mobility sector by assisting local authorities in designing appropriate behavioral interventions. To do so, ten city representatives including sustainability experts, and city managers were chosen, and semi-structured interviews were carried out to thoroughly understand their needs and expectations in terms of selecting the most effective nudges for encouraging citizens to use more sustainable modes of transport. The collected data were analyzed applyingtheThematicmethod. Finally, using the Value Proposition Design model, the design characteristics for the development of an ‘Intervention Design Tool’are determined. Our findings reveal that features such as simulating scenarios and interventions based on the behavior context and then providing users with situation-aware nudges are crucial for the creation of an 'intervention Design Tool’. Furthermore, this device must provide city representatives, as the main user of the tool, with a comprehensive view of the targeted city while alerting them to crucial situations and trends. As a consequence, the benefits that city representatives obtain from using this tool include reducing effort and saving time while increasing the reliability of their decisions.