Two people had to be freed from their vehicles after a two-car crash which shut the A140 at Long Stratton.
The crash happened at around 4.50pm on New Year's Eve, with police closing the road.
It remained shut for almost five hours while emergency services attended and investigations were carried out by Norfolk police, only re-opening at just before 9.40pm.
South Norfolk Police had said on Twitter: 'Two vehicle road traffic collision at A140 Long Stratton. Road is blocked. Please avoid the area. Likely to remain shut for a period of time.'
Inspector Jason Selvarajah added: 'Emergency services on scene at a road traffic collision. A140 Long Stratton road is currently closed in both directions. Please avoid the area.'
Firefighters from Long Stratton and Norwich's Carrow station went to the scene. Firefighters used special equipment to release two casualties from their cars.
They said they had been handed into the care of the ambulance service.
The East Anglian Air Ambulance also attended. Anglia One was called out from Norwich at just after 4.50pm. It was seen leaving the scene at just before 6pm.
The road was shut between Stratton St Michael and the Hempnall crossroads, with diversions being put in place.
The busy stretch of road between Long Stratton and Tasburgh is an accident blackspot, with two injured in a crash on December 19 and three cars involved in a crash in November with drivers escaping with minor injuries.
In October, 17-year-old Shannon Ann Gittings died following a crash on the same stretch of road.
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