How can I edit my terrain around a street curb?

I got this asset but I cant get the terrain to come up between the street and sidewalk without it covering the street. Can anyone help me out with this?

Don’t raise your terrain over your street. If you get a flat gap between your street and the terrain or between the terrain and the sidewalk, patch it with a mesh and bear the cost of modeling meshes and possibly extra draw calls. Alternatively, increase resolution on the heightmap, but then bear the cost associated with more triangles or larger heightmaps.

Or work within the constraint that terrain height locations are discrete (solve the problem by ignoring it and laying out your town so it isn’t a problem).