Rule Priority vs Rule Exception difference from legal perspective in driving rules

Question

I am from non law background, but struggling to understand what types of rules will qualify as rule exception and what falls under rule priority. As if we go to rule book like California DMV or German traffic rule book there is mention of what to do in case of exception, so it means we can not have rule exception as we still follows rule book. Like "at uncontrolled intersection default rule is right before left in right hand driving country but if we have traffic light or symbol rule applicable for this new scenario takes higher priority". So this kind of situation falls under rule exception or rule priority? As we are exempting base rules of right before left in favor of new rules.