"I did not think I was going 154 kilometres. [Police] would not show me the speed," he said.
Judge Moss told Kapene it was irresponsible to drive at such speed, as he could have lost control and crashed into a power pole or even worse - he could have hit a pedestrian.
"Do you know how often people have been killed in the street because a car was going 50 kilometres an hour? Pedestrians get killed at 50 kilometres an hour. You are 100 per cent likely to kill someone at this speed. If you hit a power pole you reduce your chances of survival, if you are speeding."
Mr Wilson said he had attended many fatal crashes involving speed and power poles.
"You don't have to be travelling very fast," he said.
Judge Moss told Kapene if he was upset, he should not have got behind the wheel of a car.
"You are more likely to use your car as a weapon. Go for a run, it really does work," she said.
She sentenced Kapene to 40 hours' community work and disqualified him from driving for six months.
