Texas man Ron Martin was arrested last October for warning drivers of an upcoming speed trap.

​"Well, the officer, who was in an unmarked car, knew something was going on when people were waving to him." ​(Via WJW-TV)

Martin stood in the median of a six-lane road and held a sign that read, "Police ahead." But he said he was just trying to get people to slow down — for safety, not to stop them from getting tickets. (Via Daily Mail)

"Martin says he and the police are on the same side."

​Martin, however, was arrested on a violation of a city ordinance prohibiting "homemade" signs on public property, making this a First Amendment concern. He recorded his arrest on his cell phone. (Via WFAA)

Martin entered a plea of not guilty to the misdemeanor in court on Wednesday, claiming he wasn't a business and therefore wasn't advertising — he was simply acting like a living, breathing speed limit sign.

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