A 27-year-old woman and two men aged 25 and 23 were killed in the crash on Radford Road, Leamington Spa, Warwickshire, at about 02:45 BST.
Two men, aged 21 and 20, were described as stable in hospital.
A 20-year-old man was arrested at the scene on suspicion of causing death by dangerous driving and driving under the influence of alcohol.
A blue Citroen Saxo travelling out of Leamington crashed near to the junctions of Willes Road and Eastnor Grove.
The three people who died had multiple serious injuries, while the two injured men were taken to University Hospital Coventry and Warwickshire.
One suffered serious leg and head injuries and the other had back and neck injuries.
Three people died and two others were seriously injured when a car hit a tree and a wall in the early hours.