The A414 North Orbital Road, near the junction with the A1(M) northbound, is closed following a two-vehicle collision.
The collision took place prior to 9.31am today (Wednesday, March 13), when a grey Skoda Karoq and a black Mazda 3 Takuya crashed near the slip road.
Hertfordshire police attended the scene, along with the East of England Ambulance Service.
Officers have advised motorists to avoid the area.
Follow our live updates on the incident here.
A spokesperson for Hertfordshire Constabulary said: "Police were called at around 9.31am today (Wednesday, March 13) to report a road traffic collision Involving a grey Skoda Karoq and a black Mazda 3 Takuya, on the A414 near to the northbound slip road to the A1(M) in Hatfield.
"Officers are in attendance with colleagues from the ambulance service and the road is currently blocked.
"We would ask all motorists to please avoid the area at this time."
An East of England Ambulance Service spokesman added: “We were called just before 9.45am with reports of a road traffic collision on the A414 in Hatfield involving two vehicles.
“Two ambulances were sent to the scene. No transportation to hospital was required.”
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