How do I report a road rage incident with an Illinois Dept of Transportation worker??

I was driving on an exit ramp when an IDOT truck pulled onto the exit ramp from the side of the road. We almost collided! He followed me to the gas station and walked up to my car. He yanked on my door handle to open my door. Thank God it was locked! I rolled down my window to apologize, but he stuck his finger in my face and started cursing and screaming at me and other passengers in my car. I was so frightened that I rolled up my window and called the police. The police arrived and totally took his side. When I asked to file a complaint, I was told that he could have me fined and ticketed for not giving him the right of way. I certainly feel bad for not stopping in the middle of the exit ramp to let him on, but he had NO right to scare the crap out of me and my child and 2 friends. I feel that it was road rage. The cop said I had no charge to file, since he never touched me. I felt very threatened and scared, and my little girl was crying. WHAT IF CAR DOOR WASN'T LOCKED??????