There’s a lot you can tell about a car by its license plate. In general, the character represents the province where the car is registered, while the first letter represents the city of registration. Many abbreviations are straightforward, others represent historical toponyms (湘 for Hunan, 粤 for Guangdong, etc.). The provincial capital is always A, with the second largest city as B, and so on. A high proportion of cars with A 00 after their province character are black Audi A6s with tinted windows, the car of choice for high up officials. License plates with red characters at the beginning denote cars belonging to the armed forces: WJ is for the military police, 空 is for the airforce, 海 is for the navy, and other characters represent specific army bases. Police cars have a red 警 after them.
The Chinese and the Americans aren’t so different: just like in the US, you can get vanity plates. Lucky numbers 8, 6, and 9 are popular, especially in strings. Some people also go the dirtbag route and get the number 250 on their plates, a Chinese insult implying lesser mental capabilities.