Motorists are warned to expect delays following a crash near Junction 6 of the A1(M) in the Welwyn area.
Traffic on the northbound carriageway was brought to a standstill in the Welwyn area this evening, according to Highways England.
Queueing traffic was stretching all the way back to Junction 5 for Welwyn Garden City.
Firefighters tweeted to say they had dealt with a collision on the Welwyn Bypass Road.
A crew from Welwyn Garden City attended and carried out “scene safety”.
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