In New Zealand, vehicle registration plates (usually called number plates) contain up to six alphanumeric characters, depending on the type of vehicle and the date of registration. To be operated on (or parked on) any public road, most types of motor vehicles and trailers must be registered and display the corresponding registration plate(s). One plate must be affixed to the rear of the vehicle, and except in the case of a motorcycle, moped, tractor, or trailer, a second plate must be affixed to the front of the vehicle. If the visibility of a regular number plate is obstructed, for example by a bike rack mounted to a car's trailer hitch, a supplementary plate with the same registration number must be obtained and affixed to the obstruction (or the vehicle) such that it will be visible from the same direction as the regular number plate would have been. Standard numbering sequences Cars and heavy vehicles 1964–1987: AAnnnn 1987–2001: AAnnnn 2001–present: AAAnnn Private cars, taxis, and heavier road vehicles in New Zealand have number plates with up to six characters. From 1964 until March 2001 these number plates had two letters followed by one to four numbers (format LLnnnn), the sequence having started with AA1 and continuing through to ZZ9989 chronologically (for example, XE3782 would have been issued in 1998). An observer could therefore ascertain the approximate date of first registration of a vehicle by means of the number plate. By the end of 2000 this system had reached the end of the alphabet ("ZZ"). The series officially ended with plate ZZ9989 the sequence ZZ9990 to ZZ9999 had appeared as personalised plates years earlier. A new system began in April 2001, with three letters (starting with "AAA") followed by three numbers (format LLLnnn), with nnn starting at 100. Land Transport New Zealand also issued AAA100 to AAA103 as personalised plates, officially meaning that the first plate in the new series read AAA104. Starting with "CEA", the number ranges started with 1, as in the old system. The authorities issued this series according to the first two letters – the third letter and numbers did not necessarily get issued in sequence. Unlike in many countries, observers cannot normally identify a location of registration by simply looking at the number plate. One exception to this rule occurred when LLnnnn plates first appeared in 1964: most plates went to the regions in batches, starting with