Attempts to find all -30cm roads and lifts them to -15cm. Doesn't work for LOD. Also updates all segments (therefore lanes too) so vehicles jump up to the new height.

Thirty_Fifteen_Curb.cs

var networks = Resources.FindObjectsOfTypeAll<NetInfo>();
for(uint i = 0; i < networks.Length; i++) 
{
	var network = networks[i];
	if(network == null) continue;
	if(network.m_netAI == null) continue;
	if(network.m_netAI.GetType().Name != "RoadAI" && 
		network.m_netAI.GetType().Name != "RoadBridgeAI" &&
		network.m_netAI.GetType().Name != "RoadTunnelAI") continue;
	{
		var affect = false;
		if(network.m_segments.Length != 0)
		{
			for (uint j = 0; j < network.m_segments.Length; j++) 
			{
				if(network.m_segments[j].m_segmentMesh == null) continue;
				if(network.m_segments[j].m_segmentMaterial == null) continue;
				if(network.m_segments[j].m_segmentMaterial.shader.name != "Custom/Net/Road" && 
					network.m_segments[j].m_segmentMaterial.shader.name != "Custom/Net/RoadBridge" &&
					network.m_segments[j].m_segmentMaterial.shader.name != "Custom/Net/TrainBridge") continue;
				var vertices = network.m_segments[j].m_segmentMesh.vertices;
				var fifteen = 0; var thirty = 0;
				for (int k = 0; k < vertices.Length; k++) 
				{
					if(vertices[k].y < -0.24f && vertices[k].y > -0.31f) thirty++;
					if(vertices[k].y < -0.145f && vertices[k].y > -0.155f) fifteen++;
				}
				if(fifteen < 8 && thirty > 8) affect = true;
			}
		}
		if(network.m_lanes == null) continue;
		if(network.m_lanes.Length != 0 && affect == true)
		{
			for (uint j = 0; j < network.m_lanes.Length; j++) 
			{
				if(network.m_lanes[j].m_verticalOffset == -0.3f) network.m_lanes[j].m_verticalOffset = -0.15f;
			}
		}
		if(network.m_surfaceLevel == -0.3f && affect == true) network.m_surfaceLevel = -0.15f;
	}
}
for(uint i = 0; i < networks.Length; i++) 
{
	var network = networks[i];
	if(network == null) continue;
	if(network.m_netAI == null) continue;
	if(network.m_netAI.GetType().Name != "RoadAI" && 
		network.m_netAI.GetType().Name != "RoadBridgeAI" &&
		network.m_netAI.GetType().Name != "RoadTunnelAI") continue;
	{
		var affect = false;
		if(network.m_segments.Length != 0)
		{
			for (uint j = 0; j < network.m_segments.Length; j++) 
			{
				if(network.m_segments[j].m_segmentMesh == null) continue;
				if(network.m_segments[j].m_segmentMaterial == null) continue;
				if(network.m_segments[j].m_segmentMaterial.shader.name != "Custom/Net/Road" && 
					network.m_segments[j].m_segmentMaterial.shader.name != "Custom/Net/RoadBridge" &&
					network.m_segments[j].m_segmentMaterial.shader.name != "Custom/Net/TrainBridge") continue;
				var vertices = network.m_segments[j].m_segmentMesh.vertices;
				var fifteen = 0; var thirty = 0;
				for (int k = 0; k < vertices.Length; k++) 
				{
					if(vertices[k].y < -0.24f && vertices[k].y > -0.31f) thirty++;
					if(vertices[k].y < -0.145f && vertices[k].y > -0.155f) fifteen++;
				}
				if(fifteen < 8 && thirty > 8) 
				{
					affect = true;
					var vertexArray = new Vector3[vertices.Length]; 
					vertices.CopyTo(vertexArray, 0);
					for (int l = 0; l < vertices.Length; l++) 
					{
						if(vertexArray[l].y < 0.0f && vertexArray[l].y > -0.31f) vertexArray[l].y = vertexArray[l].y / 2.0f;
					}
					network.m_segments[j].m_segmentMesh.vertices = vertexArray;
				}
			}
		}
		if(network.m_nodes.Length != 0)
		{
			for (uint j = 0; j < network.m_nodes.Length; j++) 
			{
				if(network.m_nodes[j].m_nodeMesh == null) continue;
				if(network.m_nodes[j].m_nodeMaterial == null) continue;
				if(network.m_nodes[j].m_nodeMaterial.shader.name != "Custom/Net/Road" && 
					network.m_nodes[j].m_nodeMaterial.shader.name != "Custom/Net/RoadBridge" &&
					network.m_nodes[j].m_nodeMaterial.shader.name != "Custom/Net/TrainBridge") continue;
				var vertices = network.m_nodes[j].m_nodeMesh.vertices;
				var fifteen = 0; var thirty = 0;
				for (int k = 0; k < vertices.Length; k++) 
				{
					if(vertices[k].y < -0.16f && vertices[k].y > -0.31f) thirty++;
					if(vertices[k].y < -0.148f && vertices[k].y > -0.152f) fifteen++;
				}
				if(fifteen < 20 && thirty > 4) 
				{
					var vertexArray = new Vector3[vertices.Length]; 
					vertices.CopyTo(vertexArray, 0);
					for (int l = 0; l < vertices.Length; l++) 
					{
						if(vertexArray[l].y < 0.0f && vertexArray[l].y > -0.31f) vertexArray[l].y = vertexArray[l].y / 2.0f;
					}
					network.m_nodes[j].m_nodeMesh.vertices = vertexArray;
				}
			}
		}
		if(network.m_lanes == null) continue;
		if(network.m_lanes.Length != 0 && affect == true)
		{
			for (uint j = 0; j < network.m_lanes.Length; j++) 
			{
				if(network.m_lanes[j].m_verticalOffset == -0.3f) network.m_lanes[j].m_verticalOffset = -0.15f;
			}
		}
	}
}
var b = NetManager.instance.m_segments.m_buffer;
for(var i = 0; i < b.Length; i++) if(b[i].m_flags != 0)
NetManager.instance.UpdateSegment((ushort)i);