They come in various sizes. In some extreme cases the circle is completely inside the crossing of the roads and doesn't even require any change to the existing

They come in various sizes. In some extreme cases the circle is completely inside the crossing of the roads and doesn't even require any change to the existing roads. Like here: https://www.google.com/maps/@44.8481471,-0.6336833,3a,75y,183.9h,70.08t/data=!3m6!1e1!3m4!1szQkTAPZoBtTyulOKuCcMHA!2e0!7i13312!8i6656 https://www.google.com/maps/@44.8481471,-0.6336833,3a,75y,18...