TMR put this up on their Facebook asking who has to give way, but that's too easy. A much more complicated question is: what does the law say around indicating?
I've seen people say only blue must indicate, others say both must indicate, and yet others say neither must indicate. Which is correct?
They say "penalty unit" so that each time they increase the fine amount, they only have to update the legislation in one place - the place where the value of a penalty unit is defined. Otherwise, every time the fine amount changes, they would have to recalculate all the penalties and update the legislation in hundreds of places with a new dollar amount.