Peter Gitonga had been at a construction site with his colleagues and had boarded a matatu headed for Umoja when the incident happened on Saturday evening.
Witnesses said he yawned, stretched, and fell asleep but never woke up again.
The driver who was notified of the tragedy drove straight to the police station where police officers confirmed the death of the man.
The body was moved to the mortuary pending probe.
Meanwhile, a boy aged one year and three months drowned in a basin with water in a tragic incident in Githunguri, Kiambu County.
The mother of the boy Ann Nyambura told police the incident happened on April 19 at about 2 pm.
The woman was doing some house washing at the compound in Kamakwa village in Kanjai sub-location and had left a bucket half filled with water.
She went to hang her clothes on a line that was about 25 meters away leaving behind Victor Kuvai while playing next to the bucket.
On coming back, she found her child had drowned in the bucket with his head first.
She rescued him and rushed him to Githunguri sub-county hospital, where he was pronounced dead on arrival.
The body was taken to the mortuary pending autopsy and probe.
