Earlier quoted context omitted.
Why would the US have roughly the same baseline safety as everywhere else in 1990, but be 2x worse today?
The idea is that the US leads in safety tech adoption (which I believe is just an empirical fact) but that safety tech is reaching diminishing returns (conjecture), so that as time goes by it's tech lead helps less and less at lowering deaths per accident (relative to other countries), while it's accident rate remains higher. This is really not that important. My point is that there are a million ways to explain the…
"The US has laxer laws and doesn't enforce them as strictly" is a very simple explanation that fits the data well. It matches what I personally have seen in the US and UK, though of course that's just anecdotal.
I'm not sure if the US is ahead of the curve at all in safety tech -- things like ABS and airbags, right? The US is definitely behind the curve in adoption of traffic circles / roundabouts rather than 4-way stops.
You're correct that there could be some other reason why the US could have a higher "baseline" rate of traffic accidents; but what could that reason be? Any suggestions?
Possibly the US has a higher proportion of young drivers?