A motorcyclist who was clocked travelling at 171 kilometres per hour on a major Adelaide road last night was more than twice the legal alcohol limit at the time, police say.
The man from Adelaide's north was also allegedly unlicensed, and has since been arrested and charged with several traffic offences.
A patrol spotted the bike travelling at high speed on Main North Road at Elizabeth at about 8:15pm.
The motorcycle was tracked by the police helicopter as it headed southwards through Paralowie, and at one point was detected at 171 kilometres per hour, police said.
The alleged rider, a 53-year-old Salisbury Downs man, was arrested at an address on Waterloo Corner Road.
He was charged with driving at an aggravated extreme speed, and driving without a licence.
Police said he was breath tested and returned a reading of 0.104, and he will face court also charged with drink driving.
The man's bike has been impounded.
The incident comes after two fatal crashes on South Australia's roads yesterday, including one between a car and a truck on Kangaroo Island.
The 42-year-old woman who was driving the car was killed at the intersection of Hog Bay and Davies Roads at Pelican Lagoon, where police were called about 9:30am.
Hours earlier, a 21-year-old man from OB Flat near Mount Gambier was killed when the Toyota Hilux he was driving crashed and rolled at Monbulla near Penola in SA's south-east.
Nine people have been killed on SA's roads this year.
Police have asked anyone who witnessed the crash to call Crime Stoppers on 1800 333 000 or online.
