Two appliances and crews from Aylesbury attended.
The firefighters used hydraulic rescue equipment and a reciprocal saw to release two women who were both injured. One girl was also injured. She had been released before they arrived.
The firefighters provided immediate emergency care and oxygen therapy to the casualties before they were handed into the care of South Central Ambulance Service.
Thames Valley Air Ambulance Service and Thames Valley Police also attended.
Thames Valley Police has issued a witness appeal in relation to this incident.