Update: Police said they believe the driver of a Vauxhall Astra became unwell at the wheel and has been taken to hospital.
Two cars crashed on Tritton Road in Lincoln, causing lunchtime delays.
Two police cars and three ambulances were spotted at the scene on Tritton Road near the Dixon Street junction.
An eyewitness said traffic is not moving and all lanes are blocked.
A spokesperson for EMAS said: “We received a call at 11.29am on August 7 to Crusader Road in Lincoln.
“The caller reported there had been a road traffic collision. We sent an ambulance, a paramedic in a fast response car and a LIVES community first responder. One patient was taken to Lincoln County Hospital by ambulance.”
Police, who attended the collision at around 11.35am, said: “We believe the driver of a Vauxhall Astra had become unwell at the wheel and has been taken to hospital.”