The A46 north of Bath between the M4 J18 and the A420 Cold Ashton roundabout has been closed in both directions following a serious collision involving a car transporter.
It is believed the car transporter left the road following the collision, which involved two other vehicles.
A female occupant of one of the cars in the crash had to be cut from the vehicle by fire crews whilst in the care of critical care paramedics from the Wiltshire Air Ambulance.
The woman has been rushed to Southmead Hospital in Bristol, the closest major trauma centre to the scene, suffering head injuries.
The incident happened at around 5.30pm this evening.
The road is expected to remain closed in both directions for some time whilst recovery and investigations take place.
