I called the Illinois State Police, division of legal affairs, was transferred to a State Trooper and he told me essentially the same thing as I just read Glen said. He stated that because a cargo van is not considered a "second division" vehicle (which he informed me was 18 wheelers) one can use the express lanes with no restrictions. Except, and however, he also made sure to tell me about the 'move over' law recently enacted, which states you must move over to the right lane after a pass. No more staying in the left lane after a pass unless it is unsafe to move over at that time, and then as soon as it is safe you must move to the right. If you want more clarification, or possibly the legal cite to check for yourself, the number I called was (Illinois State Police, Legal Affairs) 217-782-7658.
Larry Badger