The incident happened at about 1.40pm on Hagley Road in the Harborne area of Birmingham
An ambulance that was transporting a patient to hospital came across the incident shortly after it had happened. A second ambulance, a paramedic officer, the Midlands Air Ambulance Critical Care Car and the Midlands Air Ambulance from Cosford with a doctor on board were also sent to the scene.
A West Midlands Ambulance Service spokesman said: “When ambulance crews arrived, they found a middle-aged man who had suffered very significant injuries.
“The man was treated at the scene by ambulance staff. He was immobilised before being anaesthetised by the doctor and was then taken on blue lights to the major trauma centre at the Queen Elizabeth Hospital Birmingham.