Natalie Plummer from Houston spent 12 hours in jail last week after trying to warn drivers of a speed trap up ahead.

According to a Good Morning America story posted on Yahoo Plummer saw police officers ticketing speeders as she rode her bike home from a grocery store last week near downtown Houston. Hoping to help drivers avoid a penalty, Plummer turned one of her grocery bags into a makeshift sign warning drivers that read "speed trap ahead." Soon, an officer drove up and arrested her, saying she was in the street where there was a sidewalk present.

"I was completely abiding by the law," Plummer told ABC's affiliate KRTK. "I was simply warning citizens of a situation ahead."

Houston police disagree. She was almost charged with a felony offense of obstructing justice, but Plummer eventually booked with a misdemeanor. After spending 12 hours in jail, Plummer was released on bond, and will soon appear in court to face her charge.

Jodi Silva, a Houston police spokeswoman, said that officers saw her standing in the street, waving her arms as she held the sign -- a description that Plummer denies. Instead, Plummer believes that the arresting officer was looking for any reason he could find to stop her from warning motorists.

"He couldn't take me to jail for holding up this sign or he would have," she told the television station. "So all he could do was make up something fake about it."

She also said that the officer searched her backpack, to which the city's executive assistant police chief, Michael Dirden, said in a statement that Plummer should file a complaint if she believes the police acted inappropriately.

State laws covering what sorts of warnings are acceptable can be decades old and inconsistent around the country. For example, flashing headlights, the most common way that drivers alert each other to policemen ahead, is legal in New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia and Florida. Other states, such as Alaska and Arizona, don't allow that. Even more confusing are the states that prohibit headlight flashing in some circumstances but not in others.