https://assetstore.unity.com/packages/tools/terrain/easyroads3d-pro-v3-469

Create unique road networks directly in Unity with both built-in customizable dynamic crossing prefabs and custom crossing prefabs based on your own imported models. Bring your scenes alive with the included side object system, a framework to create additonal objects along the road objects and intersections. Objects such as: lampposts, guard rails, fences, walls, bridges, power lines, tree lines or any other type of geometry following a path.