As only 12 letters are available, each regional code has approximately 1.7 million combinations (12 letters x 1,000 numbers x 12 letters x 12 letters). However, this is often not enough, and the problem is compounded by the fact that a registration number cannot be reused once it has been removed from the register. To combat this, selected regions use more than one two-digit code, though not many of them enjoy this privilege (considering that there are 86 regions and 99 double-digit combinations), so the numbers 1 and 7 have started to be added in front of the regional code. A shining example is Moscow, which actually had three double-digit codes (77, 97 and 99), but not even this kept up with demand, so they started adding digits. Now Moscow has a total of nine regional codes (the original three have been joined by 177, 197, 199, 777, 797 and 799). Other stricken areas include the Moscow Oblast (5 codes: 50, 90, 150, 190, 750) and Saint Petersburg (4 codes: 78, 98, 178, 198). However, as it is only a matter of time before even these codes run out, it has been suggested that the number plate format could be modified to add a fourth digit to the serial number. This would push the number of possible combinations up from 1.7 million to 17 million for each regional code.
As in other countries, you will find vehicles on Russian roads that do not have the standard number plates. Non-standard plates can often be distinguished instantly by their colour. Another tell-tale sign is that most special number plates do not have a Russian flag on the right, plus the number formatting frequently tends to be a lot different. One example is the police number plate, which has white letters on a blue background and consists of a single letter, to identify the branch of the police force, followed by a four-digit serial number, the regional code, and Russia’s international code. You can tell a military number plate by its white lettering on a black background. The plates of public transport vehicles (buses, trolleybuses, and even taxis) use black lettering on a yellow background.