Erik Spiekermann on FE-Mittelschrift, the typeface used for German license plates.
The official typeface for our license plates is now called FE-Mittelschrift, with FE meaning it is Fälschungs-Erschwert, i.e. difficult to forge. Apparently car thieves, terrorists and notorious law-breakers had been exploiting DIN’s geometric construction principle and turning E into F or 3 into 8 etc by simply using a bit of black tape or white paint.
Here are all the alphanumeric characters:
Note the tamper-resistant differences between the 6 (no notch) and 9 (notched), the E & F, the I & 1, the O & zero, the P & R, and so on.