Oh stop! The roads are fine

Here's another couple of ideas to deal with symmetry:

When making the brush, use existing symmetrical brushes placed centrally - for example different sizes of the standard circle or square brushes, or...

create just one quarter of the design, then increase the size of the canvas by a factor of 2, so that you can copy the design, rotate it, and paste it another three times to generate the symmetry. You might have to tidy the join between each of the four quadrants, but its easier than trying to do the whole thing totally freehand.