Police were alerted to the accident at the entrance of Soi Ratchadapisek 10 in Huai Khwang district. At the scene they found a crashed Honda Click motorcycle lying near a 6-metre-deep opening in the road surface, where officials had been laying underground cables.
Rescue workers used a stretcher and pulley system to lift the victim, Chai (last name withheld), out of the hole. Medics found he had suffered several severe injuries, including a broken right leg. He was rushed to Paolo Chokechai 4 Hospital for treatment.
Construction workers said that a portion of Ratchadapisek Road had been closed to lay underground cables from 10pm to 4am every night, and that they have deployed a warning sign about 15 metres in front of the opening.
Witnesses said the motorcycle rider was travelling at high speed when he smashed into the sign, lost control and fell into the hole as his bike skidded past it.