Are the letters I and O used in license plates?

[McCamille]

License plates do not include the letters I and O. Here are the relevant details: According to the 'Motor Vehicle License Plates of the People's Republic of China': 5.8.2 The vehicle management offices of the municipal public security traffic management departments in direct-controlled municipalities use license plate issuing authority codes from A to Z, which can be sequentially used after being filed with the Traffic Management Bureau of the Ministry of Public Security. 5.9.1 Serial number encoding rules There are three types of serial number encoding rules: 1. Each digit of the serial number uses Arabic numerals; 2. Each digit of the serial number can individually use English letters, with the letters O and I from the 26 English letters not being used; 3. The serial number may include 2 English letters, with the letters O and I from the 26 English letters not being used.

[KateAnn]

I specifically asked the staff at the vehicle management office when I was selecting a license plate number before, and indeed, the new license plates no longer include the letters I and O. This regulation is mainly because they look too similar to the numbers 1 and 0, which can lead to errors when surveillance cameras try to identify them. License plates start with the abbreviation of the province, followed by a combination of English letters and numbers, such as the common formats like Yu A or Yue B. If I/O were used, traffic police could easily get confused when checking for cloned plates. Even the green plates for new energy vehicles now avoid these two letters. In fact, it's not just license plates—many coding systems that require machine recognition deliberately skip these two letters.

[StAlejandro]

Nowadays, license plate codes automatically avoid the letters I and O, as explicitly stipulated by national standards. This is because these two letters are too easily misread as the numbers 1 and 0, especially in automatic license plate recognition systems. The structure of license plates is actually quite meticulous, starting with a Chinese character abbreviation representing the province, followed by a letter identifying the city, and ending with a combination of five digits and letters. In practice, vehicles on the road, such as those starting with Hu D or Chuan Q, will never include the symbols I/O. The design of new energy vehicle license plates has also followed this rule recently.

[FinleyRose]

I only realized when changing my car license plate that all Chinese license plate sequences automatically exclude the letters I and O. This design is quite practical, preventing confusion with the numbers 1 and 0. The license plate numbering rules are actually quite scientific: Chinese character provincial identifier + letter representing the city + five-digit alphanumeric code. In the traffic management system, formats like Lu F and Jin A don't reserve positions for I/O. I heard that in earlier years there were indeed license plates with O, but due to high misidentification rates, they were uniformly phased out. Now even the vehicle license system has automatic verification functions.