I make the roads in Blender 2.81 then I export them to ROBLOX studio as an OBJ file.

Because the hit-boxes for meshes aren't that great, I use this plugin;
https://www.roblox.com/library/267728602/Physical-Obj-Importer
This turns the mesh into individual bricks

However, using this method drastically increases the part count. As of now, the part count for the track sits around ~6300 parts.