Travel routes for a vehicle from a first location of the vehicle to a second location are generated. Different alternative travel routes are calculated from a first location to a second location selected by a user for a specific vehicle in a navigation system. For each of the different alternative travel routes, both estimated emissions of the specific vehicle and also estimated fuel consumption of the specific vehicle when following each of the different alternative travel routes are computed. Subsequently, each of the different alternative travel routes are presented to a user in the navigation system in connection with corresponding estimated emissions and fuel consumption for each of the different alternative travel routes.