The accident happened at 5.30pm on the Bang Khun Non local road heading to Charansanitwong Road in Bangkok’s Bangkok Noi district.
Panadda Akkaradamrongdej, 35, was injured when the weight of the pipe, measuring 15 metres in length and with an 80-cm diameter, caused the front passenger seat airbag to deploy. She was rushed to the Thonburi 1 Hospital.
Her friend, the driver, Natthaija Chanthanakhiri, 33, told police that she saw the tube swaying before falling but she could not move her car to avoid it because there were vehicles both in front and behind.
The pipe was being used for piling work at the construction site.
Had it fallen on the roof, both women could have been killed, police said.