and therefore enjoy the comfort of the highest levels of diplomatic immunity. In order to protect the privacy of foreign diplomats, the government does not release information on embassy vehicles, so it is possible that some data in the list of plate prefixes below may not be correct. Other types Vehicles for use in automobile tests, vehicles for use in driving schools (examination and test-driving), and vehicles at airports all have their own separate licence plates. For automobile tests, licence plates consist of black characters on a yellow background with the suffix shi (试 short in Chinese for ce shi or test). For driving schools, different plates apply for test-drive vehicles (jiaolian che) and examination vehicles (kaoshi che). Airports have licence plates with white characters on a green background with the designation min hang (). This shade of green is slightly lighter than the variant used on normal licence plates prior to 1992. Some vehicles belonging to airports that operate in its vicinity (rather than inside its perimeters) have dark-green lettering on a white background. These plates, unlike others, permit the use of letter I (as in the SPIA-A00 series used in Shanghai Pudong International Airport) Sometimes, to avoid privacy invasion, modern Chinese TV show series are set in fictitious locations. Vehicles featured in these shows often carry registration plates with non-valid provincial abbreviations and/or invalid typefaces. Cross-border with Hong Kong and Macau Licence plates with a black background and the character or in place of the last number are used for Hong Kong and Macau vehicles, respectively, when they engage in cross-border traffic to and from Mainland China. These plates often exist side by side with a local Hong Kong or Macau licence plates on the same car. See the section on Guangdong license plates. Interim licence plates Interim licence plates are a piece of paper to be affixed to the front of the vehicle's window, usually valid for 15 days. Shortlived 2002 standard For a short while in the summer of 2002, a new 2002 standard was instituted in several cities, including Beijing. They enabled number/alphabetical customisation. (The possible combinations were NNN-NNN, NNN-LLL and LLL-NNN, where N would be a number and L a letter. However, although the usage of "CHN", to designate China, was not permitted in the plates, that restriction, oddly enough, did not apply to the letters "PRC".) The VIN was also added to the