Huh, interesting. Is there a red on white variant, or is it only red on yellow?

Because, at least in all ex-ussr countries, that are all supposedly Vienna convention signatories, red circle on white background means no entry but everyone I described in previous message can safely ignore it. It's to be placed in like factories, residential blocks you dont wanna people to just drive through, during road repairs, in government territories like police stations and courthouses, and on public transit parks like for trolleys and buses. You can safely drive into, but if a cop catches you there, they will ask for credentials to justify you being there. And it's not uncommon to see trucks on sidewalks and in public parks behind this sign unloading goods to nearby stores, which they are allowed to as long as they're actually unloading and not just driving through, which is very annoying when they block the entire path.

And for places that are really pedestrians only, most of the time there's a different sign, with a car facing forwards, with headlights and grill visible, like this. Still allows all the above, minus the "live or work there" caveat, so no normal cars or trucks, plus allows bicycles and horse carriages.