At 2.45am, we were called to a report that a white van had mounted a kerb and collided with a man in his 20s, narrowly avoiding a second man.
Officers attended and found the man in his 20s with serious head injuries.
He was transported to Queen Alexandra Hospital. His injuries are not thought to be life threatening or life changing at this time.
The second man, also in his 20s, was not injured.
Officers believe that there were a number of witnesses in the area at the time who may have seen or heard what happened.
Police would like to hear from anyone who may have information which could assist our enquiries.
A 27-year-old man from Cardiff has been arrested on suspicion of attempted murder, driving a motor vehicle dangerously and driving a motor vehicle when alcohol level is above the limit.
He remains in police custody at this time.
Anyone with information should call 101 quoting reference 44210199106.
Alternatively, call Crimestoppers anonymously on 0800 555 111.