Many bus routes in the northwest and west suburbs were originally operated under contract by Commuter Bus Systems. Commuter Bus Systems was formed in 1973, and normally operated school buses painted white. But by 1986, Commuter Bus Systems was no longer in operation, and various school bus companies were operating the buses, usually using school buses. Although all day routes usually used regular transit buses. In 1997, Pace began providing the school bus companies with its own smaller transit buses, for rush hour feeder service.
The largest school bus companies serving Du Page County were Du Page Motor Coach Co. (several locations), Valley Transit (Hodgkins), and Kammes Bus Service (Wheaton and Batavia). Around the 1980's these companies were acquired by Vancom, which had evolved out of an original school bus company, Van Der Aa Bus Lines, based in South Holland IL. In 1997, the Vancom school bus operations were sold to Canadian company Laidlaw, which in turn in 2007 was sold to First Group of Great Britain. The school bus operations became known as First Student.
Notable school bus companies serving northwest Cook County were Scholastic Transit Co., and Westway Coach. In 1986, Scholastic Transit Co. was sold to Ryder Student Transportation. Prior to then, Ryder System's business was primarily in trucks, including rentals. In 1999, Ryder Student Transportation was sold to First Group of Great Britain. Westway Coach is still in operation, but by the late 1980's ceased to contract with Pace.