Physicist Dmitri Krioukov probably isn't the first person to talk his way out of a traffic ticket, but the University of California researcher got a $400 charge dropped by writing a paper asserting that the cop who pulled him over hadn't actually caught him driving through a stop sign. "The Proof of Innocence," deposited for posterity here, was "awarded a special prize of $400 that the author did not have to pay to the state of California."
Krioukov claims that the officer thought he had seen him speeding through the sign because of three factors. First, the officer was viewing Krioukov's Toyota Yaris at an angle, causing it to appear as though it were speeding up as it approached him and making it look more likely that he had run the sign. Second, his speed when nearing and leaving the sign wasn't that different from what would have happened if he'd driven straight through: he says that because he had a cold, he sneezed and hit the brake quickly, stopping completely right before the sign and then accelerating quickly afterwards. Third, his tiny Yaris was obscured by another car at the moment it stopped, meaning that the officer didn't actually see it at the moment it stopped.
The paper follows this up by calculating the potential speed and acceleration of the Yaris in order to determine whether the factors could have led someone to confuse an innocent fast stop with a prosecutable traffic violation. According to Krioukov, "the judge was convinced, and the officer was convinced as well." However, he's still asked PhysicsCentral readers to "find the flaw in the argument," so the physicists among us may want to give this paper the peer review it so badly needs.