KEY POINTS:
The teenager who fell off a friend's moving car while car surfing underwent urgent surgery to relieve pressure on his brain yesterday.
The 18-year-old, who was thought to have been drinking, rode the boot of a Mitsubishi Lancer about 50m before falling off the back of the car in Takapuna on Sunday night.
The driver, also an 18-year-old male, was on a restricted licence, which meant he was not legally allowed to carry passengers.
However, he had not been drinking.
The car surfer was taken to Auckland City Hospital in a serious condition.
North Shore police area commander Inspector Les Paterson said the teen's condition had since deteriorated.
A hospital duty manager said he was in a stable but critical condition last night.
Mr Paterson said a decision would not be made until next week "at the earliest" about whether the driver would be charged.
Executive director of the Brain Injury Association of Auckland, Harley Pope, said teenagers were risking a life sentence of serious brain injury by car surfing.
"Such injuries can kill or blight the rest of a person's life.
"The brain, unlike a broken leg that can be fixed with a few weeks in plaster, may never fully recover. Brain injury affects not only the immediate victim, but the lives of a whole network of family and friends are also disrupted.
"There are already huge demands on medical and rehabilitation resources without young people recklessly courting danger in this way," Mr Pope said.
"Let's encourage our young people to test their mettle in the many sporting and adventure options available rather something like car surfing that can so easily have tragic consequences."
Car accidents are the most common cause of brain injury.
Effects include physical disabilities, sensory disabilities, personality changes, cognitive disabilities and memory loss.
