Press charges against him, since he assaulted her. If she was considered speeding, and her truck is monitored like she claims, then she will suffer the consequences of that with the company. He got in her face first, so he escalated it all first because he did not like the fact she was talking back to him.
He initiated the escalation, so he is ultimately the one wrong. Also, don't those trucks have a "how is my driving" number on them? He could have called in to report her without the confrontation. Too many of them feel like they are perpetually deputized to police non-White people. He could have used the correct channels to rectify the problem.