An ambulance driver was arrested on suspicion of drink-driving after he was involved in a seven-vehicle accident while answering a 999 call.
Four people received minor injuries in the crash, with one treated for a suspected broken leg and another suffering a suspected fractured pelvis.
A third person suffered whiplash.
The 39-year-old driver was questioned and released on police bail until January, Nottinghamshire Police said.
He has been suspended by East Midlands Ambulance Service (Emas).
The ambulance service has launched an internal investigation into the collision on the A52 in Nottingham on Saturday evening.
At the time of the crash, the ambulance was en route to an emergency call and was not carrying a patient on board.
The patient it was on its way to was already being attended by a fast response vehicle and was transported safely to hospital by another ambulance, Emas said.
Diane Lee, director of operations, said: "We sincerely regret the injuries and inconvenience caused to members of the public involved in this incident.
"The driver of the vehicle was arrested at the scene and has been suspended pending the outcome of this investigation and the police inquiries.
"We expect high standards of professionalism from our staff and we normally see that in all that we do."Reuse content