Three of them are passengers who died when their matatu lost control and landed in a ditch on the Kisii-Keroka highway, wounding 17 others.
National Traffic Commandant Benson Kibui said the matatu was overloaded and speeding at the time of the accident.
“We lost three passengers on the spot in this accident,” Kibui told Capital FM News on telephone, adding “the matatu driver did not adhere to the regulations.”
The accident occurred at about 10 am.
Earlier at 6 am, a mini truck driver was killed when his vehicle crashed on two other trucks on the Nakuru-Naivasha highway.
The driver was headed to Nakuru from Gilgil when the vehicle suddenly veered off the road and hit an oncoming truck on the opposite side, according to police quoting witnesses.
The accident at Mbaruk, considered a black spot left three other people with serious injuries.
Kibui said there are chances the slain driver may have dozed off on the steering wheel thus losing control of the vehicle.
“We are investigating the cause of the accident, but the driver most likely dozed off and lost control of the vehicle,” he said.
Kenya Red Cross said the injured people were taken to the Nakuru for treatment,
He has urged motorists to strictly obey traffic regulations to curb road carnage, particularly during this festive season.
Kenya is implementing tough traffic regulations enhanced recently with stiffer penalties targeting both private and public vehicle operators.
The east African nation has one of the worst road safety records in the world, with official statistics showing at least 2000 people are killed in accidents annually.