Three vehicles crashed during this morning's rush hour.
Police and paramedics were called to Hartspring Lane, near Bushey, just before 9am.
There had been a collision involving a white Toyota Prius, a black Mercedes CLA and a red Fiat 500.
Hertfordshire Constabulary says a woman was taken to hospital with a neck injury.
Road closures were put in place while emergency services dealt with the crash.
It led to queues both ways on the A41 approaching the Hartspring roundabout, while drivers heading towards Bushey from Radlett were turned around.
Roads were reopened at around 10.30am.
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