Thames Valley Police cordoned off the area when they were called to the scene after reports of a collision between a vehicle and a pedestrian on the first floor of the Craven Road building.
The hospital has announced that following investigations by police and emergency services, patients can once again make use of the multi-story during their visit.
Royal Berkshire NHS Foundation Trust said: “We can confirm TVP are investigating an incident in the hospital car park and we are working closely with their officers to establish exactly what happened.
“The hospital car park is now open to patients and visitors.”
Patients have been informed that they should attend the hospital as planned if they have an appointment.