A speeding car ran over three persons, including a policeman on duty, near Light House on Kamarajar Salai in the early hours of Saturday.
Police have registered a case against the driver, a college student, and have charged him with drunk driving.
Police have impounded the white sedan that the 21-year-old was driving in its mangled state as evidence.
Two other occupants, including his sister, have been booked for abetment to drunk driving.
Three others injured in the accident were treated as out-patients in government hospital.
Three vehicles parked on the road were also damaged. According to the FIR filed by the Anna Square traffic investigation police, the car was on Kamarajar Salai at 3.30 a.m and proceeding towards Adyar.
The driver lost control of the vehicle and hit a barricade outside Light House and swerved left.
The car first hit a 22-year-old man, then the constable and a woman, killing all three on the spot.
It stopped on the opposite side of the road after hitting a bike and two cars. The victims were identified as Arjunan (22), police constable S.Sekar (43) and Thilakavathi (33).
Karunasagar, Additional Commissioner of Police (traffic) said Government General Hospital doctors had inspected Anbusurya (21), who was driving the car, and certified that he was under the influence of alcohol. He is undergoing treatment in a private hospital.
His sister Adhilakshmi (26), who suffered injuries in the accident, is undergoing treatment in the same hospital.
Their friend Krish Sebastian, the third passenger in the car, has been remanded in Puzhal prison.
The police have registered a case under sections 279 (rash driving or riding on a public way) and 304(II) (punishment for culpable homicide not amounting to murder) and 337 (Causing hurt by act endangering life or personal safety of others) of the Indian Penal Code. Cases were also registered under sections 185 (driving by a drunk person) and section 188 (punishment for abetment of certain offences) of Motor Vehicles Act.