A car crashed into a barrier on a major road out of Watford.
Stephenson Way has reopened following the crash which happened at around 6pm, close to Waterfields Way.
The dual carriageway out of town towards the M1 was completely blocked with a police officer at the scene confirming someone had to be cut out of a vehicle.
The extent of any injuries sustained in the collision are unknown at the moment.
Paramedics and firefighters also rushed to the scene.
An East of England ambulance spokesperson said: "We were called at 6.11pm yesterday with reports of a collision at the junction of Stephenson Way and Beechen Grove, Watford.
"We sent two ambulances and took one man to Watford General Hospital for further treatment."
Police took the quick decision, at around 6.20pm, to turn around stranded drivers in Stephenson Way, who then had the option to join Waterfields Way or rejoin the ring road.
Police officers helped manage the tailbacks and chaos which followed by directing traffic at the nearby roundabout.
The Stephenson Way closure caused major traffic problems in the area.
Waterfields Way towards Bushey Arches was gridlocked for more than an hour, and there were also delays on the ring road and into town in Stephenson Way.
The road was fully open by 7.50pm and all delays have cleared.
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