UPDATED 10/24/11 8:04 a.m.

BOLINGBROOK, Ill. (CBS) — Some extra drivers got on the Stevenson Expressway Monday morning, but their purpose is to help relieve congestion instead of adding to traffic troubles.

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Meanwhile, Pace is set to go public with its plans and expectations for the first of its bus routes to be allowed to use the shoulder of the Stevenson Expressway.

As CBS 2’s Kris Habermehl reports, starting Monday, Pace bus drivers will hit the shoulders on the Stevenson in training during morning and afternoon travel times when traffic is most congested.

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Afterward, a public forum on the bus-on-shoulder program is set to take place from 4:30 until 7 p.m. Monday at the Bolingbrook Village Hall, 375 W. Briarcliff Rd., in Bolingbrook.

While the practice runs are in progress, the first buses on routes 755 and 855 to carry paying passengers on the shoulders won’t run until Nov. 14.

Pace has invited dignitaries to try out the shoulder ride Nov. 7.

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Spokesman Patrick Wilmot says Pace buses will use the left shoulder for much of its run. The rules are patterned after those used in Cincinnati — a city that has never had an accident blamed on a shoulder-riding bus.

One of the primary rules involves speed. The buses will not be allowed to roar by stopped cars while going 55 miles an hour.

Wilmot said that the buses will be limited to a top speed of 35 miles an hour on shoulders, or 15 miles an hour more than the traffic around them, whichever is slower.

Buses will use shoulders only if traffic is moving slower than 35. Otherwise, they will remain in the main traffic flow.

Despite those restrictions, Wilmot said that Pace expects big increases in ridership on the two routes. Both originate in Plainfield. The 855 bus goes to and from the Loop, terminating at Michigan Avenue and Superior Street. The 755 runs to and from the Near West Side Illinois Medical District. The fare will continue to be $4 each way for adults, with a reduced fare of $2.

Just because buses will be using the Stevenson’s shoulders, don’t be thinking that you can follow in your car or truck. Illinois State Police expect to place extra patrols on I-55 to spot and ticket motorists who do so.

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If the first four months prove successful, Pace expects to add service on both routes in April. Pace is already studying other expressways and tollways for similar use.