How to Use:

• Download the .blend file.
• Append the “Not-Enough-Roads-v2” collection into your scene. This will import 4 predefined presets.
• Choose the preset you need and start editing the appended road by drawing\extruding the curve or select another curve in modifier menu.

Nodes description

Main “Not Enough Roads” node

General

• A setup panel for selecting the landscape for road snapping and for choosing a single curve or a collection of curves, which will form the mesh.
• Optional "Subdivision surface"
• Switching between 4 materials
• "Trim Road" erases material from start and end of curve to make smoother transition.
• "Extend Curves" grows curves from start and end. 

Width and Height

• Precisely edit topology of every edge loop of the mesh to achieve any desired width and height.
• Segments can be merged by assigning identical numbers for a simpler mesh.
  

Flatten Road

• Corrects road's tilt on slopes and "Smooth Iterations" to smooth terrain unevenness.
• "Junctions" disables flattening at intersections to avoid heavy overlapping, and "Blur Junctions" creates smooth transitions. 
  

Camera Culling

• An optional panel for setting up culling to remove road objects (Fence, Street Light, Utility Pole) outside the camera view.
• Fill the fields with your camera values.
• Could be necessary to increase "Padding" to avoid pop-in/disappearing objects or shadows.
• "Safe Zone" disables camera culling within a specified range around camera.
• Deselect camera from every node until rendering if you experience slowdown while moving camera

Fence, Street Light, Utility Pole

• Select the side for instances.
• Specify the offset from the middle.
• Enable culling (if needed and previous panel is configured).
• Street lights can be set to light-only culling if you experience rendering slowdowns.
• Adjust the light intensity or color by modifying the original "Point" object or placing your own light source.
• "Gap" defines the distance between each object.
• "Junctions" removing instances at intersections.
  

Remove by Curve

• A panel for removing objects or editing material manually.
• Select a single curve or a collection of curves for removal.
• Adjust "Range" for distance from the curve and "Blur" for smoother transitions.
• "Texture Range" offsets the distance from "Range".
• "Snap to Surface" aligns curves with the road without manual adjustment. 

"Vegetation for Not Enough Roads" node

Camera

• Similar to the previous node but includes an additional "Distance" option. 
• "Start" is beginning of density reduction and "End" is where instances will stop spawn completely.
• Big objects like trees requires wider padding and especially if it has long shadows.
• "Safe zone" disables camera culling in specified range around camera.

Distribution

• Select collection of instances which will be scattered on a mesh.
• "Grow Zone" is an area defined by curve or curve circle where instances will appear but not outside.
• "Density" - number of instances.
• "Distance Min" is minimal distance between instances.
• "Viewport Reduction" decreasing "density" for viewport only to improve performance without disabling modifier.

Transform

• "Scale Multiplier" can be used to scale your instances.
• "Scale Z Multiplier" squeezes instances by z axis only.
• "Shift" is lowering position of instances.

Clumping

• Scaling and removing instances using scalable noise texture to create more natural distribution instead of plain.

Offset From Path

• "Offset Start" and "Offset End": Removes instances within a specified distance from the middle and ends of the road, respectively.
• Can be used to optimize number of instances by removing furthest from path.
• Blurring options for smoothing transitions.

Other

• "Junctions" removing instances on intersections.
• "Instance on Line" allows distributing instances on the middle line of road

Remove Density

• Select single curve or collection, specify distance, smoothness and instances will be removed around curve.
• "Remove on Slope" removes instances based on steepness of terrain "generally useful for landscape".

Simple Wind Simulation

• Changes rotation of instances based on noise texture
• Adjust speed, noise scale, intensity as you need
• Not recommended high intensity 
• To enable, write "#frame" in the first field which has the same name. (Yea, that is weird way but any other ways updates whole node every frame even if turned off)

"Flatten Road" node

• This node made to flatten landscape for road. It affects only defined "Radius" from road and not whole terrain.
• Select curve or collection, adjust radius, and Iterations if needed and that is it.

Important notes and suggestions:

• I recommend extruding curve or using "ctrl + rmb" instead of drawing tool to have mor control and avoid any weird curve overlapping.
• If you see dark artefacts around vegetation - increase transparent bounces in render settings
• If you see vegetation or shadows pop in - increase padding of camera culling. Every vegetation layer can be configured individually.
• You can add as many vegetation layers as you want by duplicating node and choosing different collection and configuration.
• If you experience crashes with large roads, turn of road's objects (fence, street lights, utility poles) and vegetation until rendering.
• If your GPU "out of memory", setup "camera" panels in every node and enable camera culling with distance culling.
• Adaptive Subdivision adds a lot of realism and can be quite vram intensive at standard settings. Some tweaking may be needed.
• Absolutely recommend disabling vegetation, turning off simulation and deselecting camera from all nodes until rendering or you will get slow playback with large roads.
• If you don't see vegetation - check render distance or culling options and make sure if node turned on.
• There is no simple way to export road into another software.
• If you are going to use this scatter on another mesh, set "Offset End" to 1 and "Offset Start" to 0 (default values)
• If scattered on landscape vegetation overlaps with road, you can use road's curve in "Remove by Curve" panel of landscape's scattering modifier to delete vegetation near road.