This post at Statistical Modeling suggests structural causes for an increase in traffic deaths, as opposed to the individualized "pandemic malaise" causes. That is, congestion in traffic reduces speed and rewards safe driving within the design of the streets and roadways.
I think it's similar to something I saw a bit ago--suggesting that a rise in crime was due to a changing mix of people on the street --i.e., the conservative, risk-averse people stayed away.
My therapist was deeply impressed by nuclear energy; he called it the self-destruct engine where the chain reaction got out of hand and applied it to individual psychology.
I'd apply the metaphor of nuclear reactors to now--society consists of older and younger, risk-seeking and risk-averse, conformists, and rebels. In any situation, whether driving or just interacting in public, patterns of behavior take into account all the variations. From 30,000 feet it seems the old/conformist/risk-averse component tends to act to moderate interactions, whether it's speed of driving or interpersonal conflict. When the composition changes by changing the relative proportions of the population, you get a change in society.