I do not really see a problem with traffic enforcement on truly dangerous roads. I think any sort of enforcement should be done without any sort of police traps. Cops should be out in the open so that people see them and slow down. Anyone who gets a ticket in such a scenario only has themselves to blame.
That’s not what he’s describing. They build a road that’s saft to drive at 30 and then set the speed limit to 15. It’s an invitation to “speed”. And what’s worse it makes the road more dangerous.
If police make a point of always being in the open, then no visible police = no police. Choose your speed accordingly.
While the possibility of a trap creates uncertainty. There may or may not be police. Choose your speed accordingly.
I'd argue that the uncertainty of a police presence encourages greater compliance without needing a larger presence.