Thanks to a “very unusual combination of circumstances” and a quick set of calculations, a UC San Diego scientist successfully fought a $400 traffic ticket with a four-page research paper.

Dmitri Krioukov, a senior research scientist at UCSD, successfully appealed his failure-to-stop ticket using a physics and math argument that ultimately swayed a San Diego judge.

In the paper, entitled “The Proof of Innocence,” Krioukov offered a series of equations and graphs to show that it was physically impossible for him to have broken the law, as an officer claimed.

The judge was “very, very smart,” Krioukov told The Times. “She got my point, I think, very precisely.”

Krioukov compared the problem to the way a person sees a train approaching from the platform and thinks it is moving slowly, when in fact it is barreling down the track. Using math and physics, Krioukov determined that a car moving at a constant speed can appear to move in the same way as a car that is moving fast but stops for a short time and then accelerates again.