The so-called Flex Lanes will open to Pace buses between the Elgin Transportation Center and the Rosemont Transportation Hub near O'Hare International Airport.
The change is expected to increase ridership and efficiency.
Six years ago, Pace buses were allowed to ride on the shoulder of Interstate 55. Before the program, on-time performance was 68 percent. Today, it's 92 percent.
The other part of this program is the SmartRoad technology that gives drivers real-time traffic information from overhead signage every half mile between O'Hare and Barrington.
A red "X" means that lane is closed, letting drivers know they should merge ahead.
The larger signs, every mile, will have information, such as travel times, or congestion due to a crash.
The tollway has been rolling out the SmartRoad technology for the past several months, but was 100 percent operational by Tuesday.