Young drivers are more likely to crash if they have friends along for the ride.
The risk of a fatal accident involving a young driver can be 10 times greater if there are passengers in the car.
The New Zealand Transport Agency this week started a series of advertisements aimed at young passengers as statistics make clear the danger they can pose.
Singing and sharing gossip are some of the behaviour the agency says can result in a young driver being dangerously distracted.
NZTA road safety director Ernst Zollner said evidence showed the risk of a fatal crash was increased for young drivers if they had passengers in the car.