A woman has been taken to hospital with serious injuries after a crash involving a number of parked cars.
It happened at approximately 7:40 on Sunday morning on Ynyscynon road in Tonypandy.
The woman, who was a passenger was transferred to the Royal Glamorgan hospital for treatment.
The female driver of the car was also taken for treatment and has since been arrested. Police say she is assisting them with their enquiries, along with two men who were driving behind.
Police are asking anyone with information to come forward, and have thanked the people affected by road closures for their patience.