There's something you can learn from the broad scale, but SF has pretty decent tracking and perhaps there's something you can learn from looking at one city too. SF has a Collisions Report[0] and also traffic citations data is open data[1] so you can see how enforcement has changed. Subjectively, I notice a lot more red-light running, and objectively the red-light camera near my apartment illuminates the ceiling of my home office every day.

I'm now a father so one cannot discount the amount to which my tolerance of bad actors has changed, but my experience has been that the lack of enforcement for violations (right-turn red lights in SF are rarely obeyed) is definitely taken advantage of by many drivers. However, the collisions report does make it somewhat clear that a non-trivial amount of the new fatalities are due to new traffic modalities: people now have the stand up OneWheels, and there are many more food delivery drivers on e-bikes.

But one gratifying thing is that the newer parts of town where people are having children have a lot more safety construction. I was walking home from the gym here in Mission Bay when I saw a group of kids between 6 and 12 on their little scooters.

[0] https://www.visionzerosf.org/wp-content/uploads/2023/05/San-...

[1] https://www.sfchronicle.com/bayarea/article/car-traffic-pede...