That’s if you use emissions from all “light duty vehicles”. They break it down further in the pdf, for “passenger cars” it’s more like 9%. I think the 11% was assuming you add some portion of light duty trucks to that as well but I don’t quite remember.

I’m not saying 11% +/- isn’t significant. But the transition to EVs and renewables is already going to dramatically reduce that number. So perhaps it would be more productive if Reddit devoted half as much energy as they do to cars to other sources of emissions.