Sam Ronson Arrested

Law enforcement sources tell TMZ, she was driving home from Las Vegas at 10:30AM in her black Porsche when she was pulled over for speeding.

We're told she was given a field sobriety test and didn't perform well. She refused to submit to a breathalyzer and was arrested on the scene.

She was transported to the Baker substation, where we're told she blew over the legal limit.

Sam performed at Lavo nightclub last night.