A few days ago my wife and I were traveling from Taupo to Hamilton at around 7am and were overtaken by a blue Skoda wagon going very fast. I decided, what the heck, I'll just follow him. Well he was speeding up to 140km/h and overtaking cars and trucks all the way until he caught up to another Skoda wagon that was black just south of Atiamuri. They both continued to speed around the 110 to 120km/h until pulling off at Tokorua. I didn't realize it at first, probably because it was foggy, but they both had long aerials on the roof. I said to my wife, "I think they are under cover police cars".  However, I still continued to follow them at a fast speed and a couple of times I thought of overtaking but thought I better not risk it. There was one time they slowed down to just over 100km/h before Tokorua and at that point a police car came past in the opposite direction. After that they just sped up again.
Whether they were actual police cars, I don't know, but one thing for sure it made the trip a lot faster.

Ha! Nothing like a police escort...