There are obviously alternatives, I don't deny that. But as good as infrastructure and cultural improvements can be, it doesn't change the fact that speeding cameras have proven themselves to be immensely effective, and don't require massive infrastructure projects, much more costly spending, and long-time cultural shifts. That's just the unfortunate reality of the situation.
I'm a big digital rights and privacy advocate, and I don't advocate for "spy cameras." I advocate for privacy-preserving systems that improve society when they can exist in such a way.
A camera that only sends your plate to a police system when you speed, and automatically sends you a ticket for endangering other people is not a surveillance system. It's a public safety measure, with justifiable, minimum data transmission requirements to operate effectively. A system that tracks every location your plate was seen is a surveillance system. That is not what non-"smart" traffic cameras are.
Speeding cameras are the first system, unless integrated with an ALPR system, in which case they become a surveillance system. I am advocating for the former, not the latter.