Don’t forget that a lot of carbon went in to making the road, the parking (deforestation or other land destruction for those should be considered too), the car itself, emissions from tyre wear, brake dust, some plastic for the single use medical devices necessitated by treatment of people struck by drivers, etc etc.

Though what is often forgotten is the insane amounts of plastic used in farming. Occlusion fabric for weeds, polytunnel skins, silage wrap, etc

I didn't forget, its just awfully hard to fit all that on a napkin.