: The "Fix Collisions" tool in version 3.6+ specifically fixes issues where terrain meshes get messy between close road outlines. How to Download and Install
Choose from a library of preset road styles including markings, striping, and median islands. Road Profiles: sketchup+instant+road+plugin+download+exclusive
It sounds like you’re looking for a breakdown of the Instant Road : The "Fix Collisions" tool in version 3