Current public transport supply on the Island of Lanzarote is clearly insufficient, and opportunities to substitute private automobiles are extremely limited, for residents and tourists alike. Therefore, this paper analyzes the possibility of introducing a tourist bus service to connect Lanzarote’s main tourist attractions, and it also focuses on a move towards public transport by tourists to reduce the CO2 emitted by excessive private car usage. This work assesses the impact of road transport in accessing tourist activities on Lanzarote Island and its implications for sustainable tourism development. The evaluation is based on the volume of CO2 emissions for the current tourist mobility model on the island and an alternative option such as a tourist bus route. The methodology employed here is the application of a geographical information system (GIS). The study analyzes how to manage the impact of road access to tourist sites through the implementation of a new tourist bus line. The study seeks to evaluate the design of a new bus to deliver tourists to key tourist activities on Lanzarote Island. A GIS-T algorithm is used to compare the level of CO2 emissions from the current tourist mobility model versus the implementation of a new touristic bus. The levels of pollution produced by the present system and the tourist route are compared, and different levels of demand for the new circuit are considered. We conclude that in order to reduce the current levels of emissions by around 15%, some 19.4% of the tourists that currently use hire cars would have to switch to the new tourist bus service.