Nine people were killed when a matatu burst into flames after ramming into a lorry on Narok-Mai Mahiu road on Saturday.
Five others who were in the Transline matatu suffered serious burns in the accident near Satellite trading centre.
Witness Peter Mwathi said the lorry had stalled after developing mechanical problems.
Mwathi said the driver of the matatu, who was on his way to Narok, did not notice the lorry.
“There was a loud bhang before the matatu burst into flames. Five people died at the scene and the other four died on the way to hospital,” he said.
“Passengers in the front were most affected as they got trapped in the wreckage. Those in the rear were rescued but with serious burns.”
He said none of those in the lorry were injured.
Naivasha subcounty commissioner Isaac Masinde said those injured were taken to Kijabe mission hospital.
“Investigations indicate the driver of the Nissan matatu was speeding,” said Masinde.