Physics proof of innocence

In the category of unimportant but highly amusing, I think many will enjoy this very short paper written by a physicist in California. It was apparently offered, successfully, as proof of his innocence in a traffic case in which he was accused of running a red light. Based on three simple and plausible assumptions, he demonstrates that the perceiving officer must have been deceived. As the author describes the work:

A way to fight your traffic tickets. The paper was awarded a special prize of $400 that the author did not have to pay to the state of California.