Settings > World generation > Road layout for new towns, it is possible to specify what the road network will look like. The default is 3x3 grids. When starting a new game, all towns on the map will fit perfectly into a grid such that even when cities merge, the road network will still be consistently composed of 3x3 grids everywhere.
However, when a user founds a new town, the road network of the new town is not guaranteed to perfectly fit into the existing 3x3 grid layout.
How can I found new towns while making sure that the road network of the new town fits perfectly into the existing road network?