[quote="Yiran You"]i don't understand based on which rule this blue car is allowed to wait or park. [/quote]
You're basically allowed to wait / park anywhere, unless it's prohibited.

And in this case, nothing in the question or picture indicates anything that could prohibit parking or waiting ...

The continuous white line on the edge of the road has no meaning. It just marks the edge.
But I understand your problem. This is not a priority road, because there is not plate and in the question is not written that it is a priority road.

i don't understand based on which rule this blue car is allowed to wait or park.

Because I don't see priority road sign, I don't see built up area sign.