The woman, believed to be in her 20s, was driving a black Renault Clio on the northbound carriageway around 7.30am this morning when she collided with a blue Ford Fiesta.
Fire crews from Wokingham and Bracknell were called to the scene - approximately one mile north of Coppid Beech - along with police and paramedics.
The Clio driver had freed herself from the car without help, however she was put on a spinal board and taken to Royal Berkshire Hospital as a precaution.
Firefighter Brett Humphreys, of Wokingham fire station, said: "She was very lucky and was quite distressed. It's really too soon to ascertain what happened - her car was mainly in the outside lane but traffic ended up in the hard shoulder.
"There was a lot of glass and debris and we had to reposition the vehicles so they weren't causing to much of a hindrance."
He added: "It was a combined effort by all three services."
The driver of the Fiesta - a man thought to be around 30-years-old - was unhurt.
Traffic was tailed back to the Twin Bridges roundabout as well as the Jennett's Park and Binfield/Wokingham junctions - causing delays of approximately 40 minutes.
Movement was also slow on the southbound carriageway - from Reading to Bracknell - due to onlookers slowing down to see the accident.