I am not knowledgeable on the technical aspects of LIDAR but I had a thought for a counter measure and thought I would ask here to see how viable it is or not. My idea is for states where no front license plate is required.
Picture a clear license plate cover or Plexiglas with chrome style reflective tint applied to the back side. This would then be mounted in front of a black carpet, felt or other matte surface slightly behind the tinted cover. The whole assembly would be mounted in the normal front license plate area and be similar size to a standard license plate. It would also be mounted at a slight angle downward ( the top further forward of the bottom ) It may be easier to picture a shadow box with the glass tinted on the inside with chrome tint facing inward.
My thought is that when LIDAR is used in this area the beam would go through the clear Plexiglas or cover and strike the matte black carpet which is least reflective. What amount of the LIDAR may be reflected would then be reflected toward the Chrome side of the tint and then be re-reflected back toward the carpet area.
This may a completely stupid idea with no relevance to LIDAR as my thinking is based on visible laser but I hope it won’t hurt to ask.