Four people lost their lives in accident at the Ogunmakin, Ogun State end of the Lagos-Ibadan Expressway.
Eight others were said to have sustained varying levels of injuries.
This was disclosed in a statement by the state Sector Commander, Federal Road Safety Corps, Ahmed Umar.
Umar said the accident, which involved a trailer with number plate, XA 802 KKM, and a Mazda bus with number plate, SHK 684 XA, occurred around 8.45pm on Saturday.
The FRSC boss added that the accident was caused by speeding and loss of control on the part of the bus driver, who allegedly rammed into the stationary trailer.
A total of 13 people were involved in the accident, with eight people got injured, while four persons, comprising three men and one woman, died.
Umar noted that the injured victims were taken to Victory Hospital, Ogere, while the deceased were deposited at the FOS morgue, Ipara.
The sector commander said the crash was due to the lack of caution on the part of the driver.
