Next Monday, Chicago’s Pace express buses will start operating on the Stevenson Expressway (I-55)’s newly widened shoulders in an effort to cut congestion and improve service, the Chicago Tribune reported.

Pace's bus-on-shoulder pilot program is the first of its kind in the Chicago area. Transportation officials consider it the most cost-efficient way of helping decongest the nation's second-most gridlocked urban area.

"The best advantage is there is minimal infrastructure investment," said Rocky Donahue, Pace's deputy executive director. "The road is already there. We're not building a completely new rail line. We're not even building a new lane to let the bus go down. It's utilizing the existing infrastructure and improving the service for all of us."

According to Pace, the goal is to make service more reliable and speed up the commute for customers who use two existing express bus routes that serve the southwest suburbs via U.S. 55. It also wants to give commuters an alternative to driving that can save time and money.

The buses will be allowed to maneuver around and past traffic jams on about 15 miles of shoulder. There are two stretches where the buses will need to stay in the regular left lane.

Buses will be allowed to use the shoulder only when traffic in the regular lanes is traveling less than 35 mph. When using the shoulder, the buses cannot travel faster than 35 mph, or 15 mph faster than traffic in the regular lanes, whichever is less.

"It's not like the bus is going to be going 75 miles an hour down the shoulder, or utilizing the shoulder when traffic is moving faster than 35," Donahue said. "It's a designated safe speed in order to allow (the bus) to get in and out of mainline traffic if need be."

Special signs and roadway markings indicate where buses can use the shoulder, and the buses are specially marked.

The pilot project is funded by a $1.5 million federal grant to improve air quality and is a cooperative effort by Pace, the Illinois Department of Transportation (IDOT), the Regional Transportation Authority (RTA) and the Illinois State Police. Gov. Pat Quinn signed legislation in August giving the project the green light. The project was first reported by the Tribune in February.

IDOT has been upgrading the expressway shoulders since spring. In some areas, the shoulders are now 20 ft wide.

The project is modeled after a successful program in Minneapolis. Buses also operate on shoulders in Cincinnati, Miami, and Columbus, Ohio.

Transportation officials hope commuters will choose to ride the bus rather than drive the expressway.