A woman has been taken to Frenchay Hospital with life-threatening injuries after a crash this morning on the A46 north of Bath.
The road reopened just before 2pm, but had been closed in both directions since the collision at around 8.30am.
It involved a Citroen C5 and a Peugeot 206 and emergency services dealt with a number of casualties.
One patient, a woman, has gone to Frenchay, with critical injuries, while two or three other patients are being treated for a range of injuries, including multiple broken bones.
Avon and Somerset Police are unable to release more details at this state.
The incident took place between the junction with the A4 London Road and Slough Lane, at Nimlet, just south of the Cold Ashton roundabout.
It was initially reported that three vehicles were involved, but this afternoon a police spokesman confirmed it was actually two.
Emergency services were called to the scene and traffic quickly built up around the area.
Recovery work and accident investigations then took place and although the road was initially closed just in the northbound direction, it was later closed both ways.
The road reopened shortly before 2pm, however traffic is still reported to be slow.
Motorists are being advised to find alternative routes in and out of Bath.
#A46 both directions btwn the A4 (Larkhill) & A420 (Marshfield) the road remains closed for ongong Police investigation & recovery work.
— Highways Agency (@HAtraffic_swest) May 10, 2014@BathTrafficZen@BathChron A46 closed from Batheaston roundabout towards M4, also bypass towards M4 is closed. Probably accident
— Tom'ek (@sworek) May 10, 2014Accident on A46, Bath and Cross Keys Road, Corsham causing heavy traffic in Batheaston and Corsham. X31, X72 and 228 may be affected.
— Faresaver Buses (@FaresaverBuses) May 10, 2014RT @HAtraffic_swest#A46#Somerset both directions btwn the A4 (Larkhill) and A420 (Marshfield) the road remains closed for Police...
— Highways Agency (@highwaysagency) May 10, 2014