Detectives are appealing for witnesses and dashcam footage following a collision on the A46 southbound.
Police were called at 3:50 pm on 12 April to a report of a Black Honda Civic on its roof on the Wanlip slip road, close to the junction with the A6.
Officers attended the scene, along with crews from Leicestershire Fire and Rescue Service and the East Midlands Ambulance Service.
Following initial enquiries, it is believed the car has collided with the reservation on the slip road but another car – a White Audi A3 – may also have been involved in the incident.
The driver of the Civic was taken to the Queen’s Medical Centre by air ambulance. Her injuries are not thought to be life changing or life threatening.
The two passengers in the car where taken to the Leicester Royal Infirmary with minor injuries.
The driver of the Audi was not able to stop safely at the scene but contacted police a few minutes after the incident occurred. She was not injured and is being spoken to as part of the investigation.
An investigation is now underway to establish the full circumstances and the moments leading up to the collision. The A46 southbound from the Hobby Horse roundabout remains closed while officers continue to examine the scene.
DC Anita Rose, from the force’s Serious Collision Investigation Unit, said: “We are eager to speak to anyone who was in the area of the A46, between the Hobby Horse roundabout and the A6 junction, and and may have seen a black Honda Civic and white Audi A3 heading southbound towards the M1.
“If you witnessed the incident or the moments leading up to the incident or have any dash cam footage you think might be useful as part of the investigation, please get in touch.”
Anyone with information is asked to call Leicestershire Police on 101, quoting incident 417 of 12 April.