Rachuonyo North sub-county police commander Lydia Parteiyie said the deceased persons were rammed into after the car veered off the road.
Parteiyie said the majority of injured people were traders who still operating at the time of the accident.
"Some were rushed to Homa Bay County Teaching and Referral Hospital for treatment," she said.
The car entered a thicket following the incident.
Some who were inside the car were also taken to hospital for treatment.
"We're yet to establish the exact number of those who were inside the car and what actually led to the accident," Parteyie said.
Road users were urged to remain vigilant and observe traffic rules as El Nino rains continue to get witnessed.
The four bodies were moved to the Rachuonyo North Sub County Hospital mortuary.