Many years ago, in Belgium they had a system where a flashing amber light indicated a junction and give priority to traffic coming from the right. This worked very well, and I also believe in some cases like major junctions in large cities the normal lights operated as required. ie in major cities where gridlock couldnt be avoided. I remember recently coming down Ross road on Saturday morning and was shocked to drive thru the Asda rounderbout, no traffic to speak of. Guess what the traffic light were out.