  Navigation apps use routing algorithms to suggest the best path to reach a
user's desired destination. Although undoubtedly useful, navigation apps'
impact on the urban environment (e.g., carbon dioxide emissions and population
exposure to pollution) is still largely unclear. In this work, we design a
simulation framework to assess the impact of routing algorithms on carbon
dioxide emissions within an urban environment. Using APIs from TomTom and
OpenStreetMap, we find that settings in which either all vehicles or none of
them follow a navigation app's suggestion lead to the worst impact in terms of
CO2 emissions. In contrast, when just a portion (around half) of vehicles
follow these suggestions, and some degree of randomness is added to the
remaining vehicles' paths, we observe a reduction in the overall CO2 emissions
over the road network. Our work is a first step towards designing
next-generation routing principles that may increase urban well-being while
satisfying individual needs.
