A 65-year-old patient, N. Balaiah, was killed when a speeding Tamil Nadu State Transport Corporation (TNSTC) bus hit the private ambulance in which he was being taken back to a hospital at Tirupparankundram late on Monday night.
Four others were injured in the accident.
Police said Balaiah of Poosalapuram in Peraiyur taluk was taken to a private hospital at Tirumangalam around 8.30 p.m. The doctor advised him to do a scan at a scan centre in the city.
After the scan was done, the patient was being taken back to the hospital in the ambulance. When the vehicle reached the round-about near the new rail overbridge, the TNSTC bus, proceeding towards Chennai from Papanasam in Tirunelveli district, dashed against it.
The police said the bus driver had been driving the vehicle in a rash and negligent manner and going almost in the opposite lane. While Balaiah was killed on the spot, ambulance driver Palpandi suffered a fracture in his leg.
Ambulance cleaner Kathiresan, hospital assistant Jeyapandi and attendant of the patient Anandarajan sustained injuries.
Tirupparankundram police are investigating.
A police source said the bus should not have taken Tirupparandkundram Road, but should have taken the Ring Road.