At least 13 people died at the crack of dawn Wednesday after a Nairobi-bound bus from Mandera rammed a stationary truck at Matuu in Machakos County.
The dead include 10 men, two women and a child, area police boss Joseph Karanja told the Nation.
Mr Karanja said the incident happened a few minutes after 5am, and that the driver of the truck that had stalled on the road had not placed warning signs (called life savers) to caution other users.
The morning crash left scores of other passengers injured and they were taken to Matuu Level Four Hospital.
The ill-fated bus belongs to Madina Sacco and plies between the capital and the northern Kenya town, near the Somalia border.
The collision comes barely 24 hours after three people and were killed in a crash at Masimba market on Nairobi-Mombasa highway on Tuesday.
At least 20 people have perished on Kenyan roads in less than a week, bringing into question the effectiveness of measures the government has put in place to arrest runaway carnage.