Mapview road shape sizes by Ice.

AIpathOffset does control in game map size of roads. Here's pic of 8 roads

And the config I used.

class RoadTypesLibrary
{
	class Road0001
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 0;
	};
	class Road0002
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 2;
	};
	class Road0003
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 4;
	};
	class Road0004
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 6;
	};
	class Road0005
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 8;
	};
	class Road0006
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 10;
	};
	class Road0007
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 20;
	};
	class Road0008
	{
		width          = 10;
		mainStrTex     = "ca\roads_e\roads\data\path_tak_ca.paa";  // lowercase!
		mainTerTex     = "ca\roads_e\roads\data\path_tak_end_ca.paa";
		mainMat        = "ca\roads_e\roads\data\path_tak.rvmat";
		map            = "main road";
		AIpathOffset   = 40;
	};
};

Once you get past 6 it seems to turn the orange “main road” white so width is road texture width, an AIpathOffset is in game map width + plus where they drive An to make matters worse, AIpathOffset = 5 would make AI drive middle of a 10 width road. But it also makes you in game map road a thin line.