The first thing to note is that the Department of Motor Vehicles is under the Department of Revenue. Something to ask yourself: if there are law enforcement officers who have a speed trap at the bottom of a hill, how many traffic accidents have occurred there in years past? If the answer is zero then they’re not there to enforce law for public safety. The Department of Revenue has extracted an incredible amount of money to come up with and apply new technologies that will continue to make them an incredible amount of money.
It used to be that license plates were just stamped and painted metal slabs, but modern license plates are a technological wonder. The remarkable shine on them isn’t accidental – it’s called a “retroreflective coating”, it was invented by 3M, and it’s remarkable because it reflects light back in the direction it came from.
Light normally reflects according to angle of incident: a 45 degree impact to a flat surface results in a reflection 45 degrees in the other direction.
On the road at night, things we perceive as really shiny such as traffic signs aren’t just really reflective, we see them the way we do because our eyes are in the same direction relative to the sign as our headlights. This results in a very bright reflection and very legible sign under almost any conditions.
When traffic cops point their laser speed reading guns (LIDAR guns) at your car, they’re trained to hit your license plate first because it has a higher reflective coefficient than any other part of the car, windshield, grille chrome and all.
This technology has a number of road safety applications, such as the jackets and helmet tape worn by construction workers, and it’s even being put into clothing to not only look cool, but protect the wearer from photographers since the clothing reflects the light back into the camera.
This technology has enabled law enforcement a great deal because it increases the range of a speed-measuring LIDAR gun many times over, and provides a clearer image to intersection cameras. This is why all 50 states have moved to use of this material for plate manufacturing and is why more state laws have been passed mandating a front plate, and that they be placed “in a conspicuous place, not behind the windshield”, because the windshield dampens its retroreflective properties.