PRELIMINARY: Preliminary investigation indicates the following occurred: Unit 1 was traveling south on Interstate 57 near milepost 221 in Champaign County. Unit 1 driver slowed speed and pulled to the right shoulder. Unit 2 was traveling south at the same location and moved to the left lane while approaching Unit 1. For unknown reasons, the driver of Unit 1 pulled back into the roadway and into the path of Unit 2. Unit 2 struck the driver side of Unit 1. The driver of Unit 1 was transported to an area hospital with life-threatening injuries. Both the driver and passenger of Unit ...