All of the victims were passengers on the bus, which was traveling from Nairobi to Kitengela at the time of the event. On Monday night, about 7:30 pm, the accident happened.
Eyewitnesses said that the bus was traveling too fast on the road when it struck the automobile, which was being cleared at the Mlolongo exit.
The two cars rolled over. Rescued people were hurried to the hospitals in the area.
According to early accounts, the bus may have experienced brake failure as a result of mechanical issues that occurred while it was on the road.
Damage to the Expressway toll station booth is severe.