Some special materials absorb in the near IR and transmit in the visible and hence this test using visible light is not indicative that a special police-lidar countermeasure is working. The license plate is the strongest target on the front of the car. Different States have a very large difference in the lidar return from the plates. Colorado is one of the lowest, using retroreflective paint on only the letters and a thin border. The strongest reflection of the rear of the car is an array of little corner cubes in the red tail light cover.
All cars have a hexagonal array in the plastic tail light covers.
These are just like a bicycle reflectors. You can distinguish these retroreflectors from the tail light lens by the array pattern. The tail light lenses are in a rectangular array, and this corner cube array is in a hexagonal pattern. The second strongest target on the rear is the rear liscense plate. There is also a corner cube array on the side-front turn signal indicators.