European Union Member States are called upon to meet internationally proposed environmental goals. This study is based, in particular, on the recommendation of the European Union (EU), which encourages Member States to pursue effective policies to reduce greenhouse gas (GHGs) emissions, including through appropriate changes in the behavioral habits of citizens. In this respect, among the main sectors involved, transport and mobility should certainly be mentioned. National institutions should be adequately involved in order to achieve the objectives set; in this regard, universities must certainly be considered for their educational value. These latter, for instance, could commit to improving the environmental performance of the mobility of their commuter students (to a not insignificant extent), since commuting modes are often the cause of high CO2 emissions; indeed, they still largely involve the use of internal combustion engines based on fossil fuels. In this paper, the effectiveness of a smartphone-app-based method to encourage commuter students to adopt more sustainable transport modes is evaluated. In more detail, starting from a statistical analysis of the status quo of mobility habits of a sample of students at the University of Palermo (Italy), an improvement of current habits toward a more sustainable path is encouraged through a new application (specifically created for this purpose) installed on students’ smartphones. Then, the daily and annual distances traveled by commuters with the new mobility modes are calculated, and the resulting savings in energy and CO2 emissions are estimated. Finally, it is proposed that the reduced emissions could be converted into energy-efficiency credits that the University could use to enter the emission trading system (ETS), here contextualized within the Italian “TEE” (“Energy Efficiency Credits”) scheme, while the benefits for students participating in the program could consist of reduced fees and free access to university services. The results obtained show the feasibility of the proposal. This approach can be considered a useful model that could be adopted by any other public institutions—not only universities—to facilitate their path toward decarbonization.