A Dunedin driver who "fell asleep" before crashing is suspected of huffing nitrous oxide while behind the wheel.
The man was heading south down Mornington Rd, Balaclava, at 5.20pm on Saturday when he crashed into a parked campervan, Senior Sergeant Craig Dinnissen said.
Police arrived and he told officers that he "fell asleep" while driving.
He underwent breath testing procedures and a compulsory impairment test, and passed both.
However, after a double-sided knife was found under the man’s seat, a warrantless search was invoked.
Police found a "large" collection of nitrous oxide canisters — also referred to as "nangs" — sitting in the boot.
Nang usage would not show up in a compulsory impairment test.
The man was charged with careless driving, and further charges are likely, Snr Sgt Dinnissen said.
He was summoned to appear in Dunedin District Court at a later date.
