The A140 was closed in both directions on Monday morning after a crash in the early hours.
Police were called to the road at Alby with Thwaite, between Aylsham and Cromer in north Norfolk at 4.25am.
Fire crews from Aylsham and Cromer also called to the scene.
A Ford Mondeo and a Ford Fiesta were involved, with the driver of the latter sustaining injuries which required hospital treatment.
The road was closed in both directions while the cars were recovered, with drivers advised to use an alternative route.
An eyewitness at the scene said cars were diverting via Aldborough heading towards Norwich.
Sanders Coaches said there would be minor delays to its X40 and X44 services, as well as its A/C bus to Norwich City College, while the A140 was closed.
The road reopened at 7.30am.
For up-to-date information about the county's roads, visit our LIVE Norfolk traffic map.
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