What is the special meaning of Beijing license plate number ABCDEFGHJKLO?

What is certain now is that brand A is generally the kind of particularly old car. For example, there was a car at home in the 1990s, and it is still driving. Then there is the government car, slowly turning in this direction.

B It's a taxi. This is no problem. O is usually used by police cars. Some cars are not painted with that blue and white paint, but they also carry the O brand. This car is also a police car.

The others are arranged according to the time of playing cards. When one letter is finished, the next letter is used. It is worth mentioning that cars in Beijing, especially private cars, are developing rapidly. It seems that it took five years from H to J, but it took 1 years from J to K (from 05 to 06, because my car was bought from J in June 2005 +0 1), and now there are even L brands on the streets of Beijing.

This figure should be in districts and counties. Anyway, the number starting with 5 belongs to Xicheng, and the number starting with 5 has its own meaning. Letters are generally far away districts and counties, and there are many cars. What I have seen most is that there are two letters behind things in Beijing, and then there are only three numbers.