I think you would need to look at how much less each nation drove, I have a suspicion that the drop in driving in the US is much less pronounced than in France

I think you would need to look at how much less each nation drove, I have a suspicion that the drop in driving in the US is much less pronounced than in France. US has a much higher driving culture, and we also had much less restrictions in most of the nation, so I suspect the reduction in number of miles driven in the US was not really that much outside the say CA and NY