12 people were Tuesday night killed in an accident at Kimende along the Nairobi-Nakuru highway.
The accident involving an 18-seater matatu and a lorry happened few minutes before 11pm, witnesses and police said.
According to the witnesses, the matatu was heading to Nakuru from Nairobi when it collided head-on with a Nairobi-bound lorry.
Nine people died on the spot while three others died on the way to Kijabe Mission Hospital. The bodies were taken to the hospital mortuary as investigations into the incident go on.
Witnesses and survivors said one of the affected vehicles was overtaking and there was poor visibility at that time because of fog.
Among those who died are primary school pupils whose books and uniform were strewn at the scene. Most schools are reopening for third term this week.
Lari Traffic Police Base Commander Ahmed Mohammed said the public service vehicle was enroute to Western Kenya from Nairobi when it collided with the lorry that was coming from the opposite direction.
Rescuers had a difficult time trying to get victims out of the wreckage.
Elsewhere, 30 police officers were last evening injured in an accident along Mwingi-Garissa highway. The lorry was heading to Kanyonyo (AP) Border patrol unit Training School when a front left tyre burst. The vehicle veered off the left side of the road facing Mwingi direction.