Prior to 1992, the New Zealand Police dealt with crime and things of that nature, while a number of cities had their own Traffic Departments looking after traffic related matters within the city.
The Government also had a nation wide traffic service called the New Zealand Transport Department also looking after traffic related matters which over a period of years became the Ministry of Transport looking after traffic matters on the highways and within areas that had relinquished traffic control to the Ministry of Transport.
By 1992 there was only the New Zealand Police and the Ministry of Transport, so the Government of the day decided to integrate the Ministry of Transport Traffic Officers into the police becoming Police Constables, thus saving a duplication of resources.
The Ministry of Transport Traffic Officers had a different coloured uniform consisting of a white shirt and black trousers and jacket while the motorcyclists had black jacket with light brown coloured riding pants and brown boots. We also had different coloured cars very much like the Californian Highway Patrol.
Over a period of time the police markings changed from black to grey and then to white and the flashing lights changed from red to blue and then red and blue as did all of the traffic departments. With the white police cars came a blue chevron along the side of the car with Police on the front door.
Then came the orange and blue "Battenburg" type makings for General Duties while traffic cars had yellow and blue. All vehicle now are being marked in the yellow and blue but only halfway down the side of the vehicle.