A question we get asked a lot. We literally got an email about it just the other day.
It is sometimes listed among the stupefying list of contents in your Owners’ Manual. If you can’t find it, the best place is behind your review mirror. A lot of cars now have metal in the glass to reflect the UV light and provide some insulation, particularly in the Euro models. It has the added effect of making some radio waves difficult to receive.
Have you ever noticed the dotty painted effect behind your rear-view mirror? It’s meant to block out the sun because the UV shield isn’t in that area. It was left so you can put Mobile aerials and toll tags there.
If you have been getting toll notices even though you have your tag mounted, this could be your problem.
Why not give it a look next time you’re behind the wheel?