CO2 is only a small part of the story
the motorcycle used 28% less fuel than the comparable decade car and emitted 30% fewer carbon dioxide emissions, but it emitted 416% more hydrocarbons, 3,220% more oxides of nitrogen and 8,065% more carbon monoxide.
So yeah. Not exactly great. And btw our option on those hydrocarbons have changed a LOT in the last 13 years when this was published. See the decline of diesels post dieselgate.
That story is over a decade old and looks at motorcycles that aren’t anything close to modern standards.
Modern 4 stroke motorcycles are more fuel efficient and all around less polluting than cars.
None of this really matters as the best form of transportation is obviously mass transit, walking or bicycle but it does make sense to split out motorcycle.
