It happened between the Preston Island in Shrewsbury and the Sundorne roundabout on the A49, at around 4.30pm.
Police and the fire service attended the scene and shut the road between the two roundabouts.
Shropshire Fire and Rescue Service said they had been called a crash that had involved two separate incidents.
A spokesman said that one driver had been treated by ambulance crews and one driver was being assessed.
The closure of the stretch of the A49 means all traffic has been diverted onto alternative routes – including the A5 around Shrewsbury.
Motorists in the area have reported large tailbacks along the Shrewsbury bypass as a result.