I seem to remember, in the seventies I think, that black and white poles went out with the demise of policemen wearing a black and white wrist band indicating 'on duty'.
The powers that be seem to have decided that a visible police presence is no longer needed and traffic lights are more and more seen as an inconvenience to many and optional to others so they've both been blended into the background.
I have to go now as I can hear the cheery whistle of the milkman and I'm sure the postman's here with the first of my four daily deliveries. I'm wondering if he onion johnny and knife sharpener are due too.