At least 12 people, including a one-year-old infant, were killed in road crashes at the weekend.
A matatu plunged into a ditch at Ngege in Sondu, Kisumu, killing four people on the spot and injuring several others.
One more person died on arrival at St Joseph Nyabondo Mission Hospital, police said.
A girl was treated and discharged while the rest were admitted with fractured limbs.
The driver was taken to Matata Nursing home in Oyugis and other passengers to Pap Onditi.
The Best Line Sacco matatu was heading to Kisumu from Nyakach Township on a narrow stretch of the Ahero-Kisii highway when it plunged in a gulley at 8:40am.
Survivors said besides the driver, the 14-seater vehicle had 21 passengers with the conductor, a student and another passenger hanging onto the door.
Nyanza Regional Traffic Enforcement Officer Andrew Naibei said the 8:40am accident may have been “self-involving”, citing human error as the most probable cause.
“By the time my officers arrived at the scene, the injured were not there,” Mr Naibei said.
Police were at the scene but the dead and injured had been moved.
Mr Simon Omondi, who lives close to the road, said he heard a loud bang and then saw a cloud of dust as the vehicle veered off the road into the gulley.
“I saw one person trapped under the wreckage calling for help, saying his leg was broken and hurting,” Mr Omondi told the Nation.
At Odongo junction on the busy Bondo-Usenge highway, two people died on the spot and nine others sustained serious injuries in an accident.
An eyewitness said the tyre of the speeding matatu, which was headed to Usenge from Kisumu, burst and it veered off the road and rolled several times.
Two men died and students heading back to school were injured.
Bondo OCPD Paul Kiarie said the 14-seater matatu had 11 passengers.
In Kakamega, six people, including a primary school head teacher, were killed and scores injured in three road accidents in Mumias and Butere sub-counties on Sunday night.
Police said a group of 15 people in a Probox car were involved in an accident at Ebwaliro on Ekero-Buyangu road, after the driver lost control of the speeding vehicle.
“Two people, including a one-year-old baby, died on the spot while 13 others sustained serious injuries and were rushed to St Mary’s Hospital,” Mumias OCPD Peter Kattam said.
The driver died later in hospital, Nurse-in-Charge Mark Simiyu said.
In another accident, a man who was going home died on the spot after the boda boda he was riding was hit by a vehicle at River Nzoia bridge on the Mumias-Bungoma road on Sunday night; it was a hit-nd-run.
Another cyclist and his passenger who were knocked down by a bus on the Manyulia-Shiatsala road in Butere at 9pm died on their way to hospital.
Additional reporting by Nelcon Odhiambo