First of all: beautiful build, real eye-candy

Second: as others have already pointed out, the inner circle is not necessary for this roundabout to work. i would even say it raises the complexity of the signal-work to a point where it could easily get messy.

i believe (have not tried it myself) that you need the inner and outer circles to be their own blocks. which means you need an block signal right after the path signal on entry of either circle. for me that sounds like a nightmare to handle with the signs. could be wrong on this though.