Merseyside Police Assistant Chief Constable Jenny Sims said the Bank Holiday Monday incident was not being treated as terrorism and was believed to be an isolated incident following the arrest of a 53-year-old man at the scene.
The force said the suspect was the driver the of the car, white, British and from the Liverpool area.
At a press conference on Monday evening, Dave Kitchin from North West Ambulance Service (NWAS) said 27 people were taken to hospital and 20 people were treated at the scene, with four children among the injured.
He said two of those taken to hospital, including one of the children, suffered serious injuries.