Three people died and two others were injured in a crash involving a truck and another vehicle on the Eastern Bypass on Wednesday morning.
Nairobi County Traffic Commandant Leonard Katana said one of the vehicles was trying to overtake another.
Mt Katana said the injured were taken to Mama Lucy Hospital but one of them was later transferred to Kenyatta National Hospital.
Mr Katana urged drivers to be careful on the road and observe speed limits.
The three who died were in the small vehicle.