Complex sentence: Driven by Gregg and carrying Joe and Jill, the truck gets its wheels stuck in heavy mud; with Jill's encouragement, Joe manages to push the truck free, and the police then get stuck in the same mud as the truck drives away.
Split into simpler sentences: Driven by Gregg and carrying Joe and Jill, the truck gets its wheels stuck in heavy mud. With Jill's encouragement, Joe manages to push the truck free, and the police then get stuck in the same mud as the truck drives away.