Thika and Ruiru sub-counties experienced eight accidents on Friday with the death toll rising to 13 while scores were seriously injured.
The survivors were admitted in different hospitals in the areas.
According to Thika Traffic Police Base Commander Apelles Chacha, the accidents were caused by heavy traffic congestion occasioned by Mount Kenya University’s graduation that was held in Landless.
Chacha said that the most of the Public Service Vehicles (PSVs) were the cause as they sped overtaking and overlapping.
She added that four accidents took place along the superhighway while the others happened in Thika town roads that were almost impassable on Friday.
Chacha, however, lauded bodaboda operators whom she said helped the police in conducting their patrols. She added that no accident involved a bodaboda operator on Friday – a clear indication that they are on the right track.
The officer was speaking when she briefed the press on the updates of the traffic on Friday evening from her office in Thika.