Police say the rising cost of fuel may be curbing boyracer activity.
In the first seven months of this year, police in Christchurch prosecuted more than 1100 boyracers for noisy vehicles - significantly more than the 800 two years ago.
But while prosecutions are up, the police say such activity in central Christchurch has actually declined.
A major enforcement effort in June, colder weather and the higher price of petrol are all seen as contributing to the drop.
