At least in the USA, root cause is the poor driving ability of an average driver. At medium to high congestion levels, it's less of a factor because the roads a

At least in the USA, root cause is the poor driving ability of an average driver. At medium to high congestion levels, it's less of a factor because the roads are so congested anyway. Once congestion drops below a certain threshold, in the USA you have these phalanxes of slow moving cars that other (also incompetent) fast moving cars are desperate to get around. Anecdotally, I personally found that the driving experience got much worse due to this effect. Whereas in Europe, people drive right and pass left. In the USA you're actually taught (if taught at all) to avoid lane changes. Now if you tell me that accident counts went up in EU as well, then ok my reasoning is wrong. OK I found https://wjes.biomedcentral.com/articles/10.1186/s13017-021-00395-8 https://wjes.biomedcentral.com/articles/10.1186/s13017-021-0... which breaks it down. I didn't read it in detail but most of the increase (but not the single greatest increase) was in the US. For the rest of world, for the most part things got better with reduced traffic. > Overall, the number of annual road death dropped significantly in most countries. However, few had the opposite. There was an overall reduction in the annual absolute number of road deaths in most of the 27 European countries by 17% [24], six Balkan countries by 11% [117], in Saudi Arabia by 20% [118], and in Japan by 12% [119, 120]. In contrast, the absolute number of road deaths increased in some countries like Luxembourg by18%, Ireland by 6%, Finland by 4%, and Switzerland by 21% [24, 117]. Similarly, it generally increased in the USA by 7% [110] with major variations in different states [121]. The study is detailed and they go more into it than just "deaths". Although I very much doubt that they get into studying driver skill.