A 48-year-old Baltimore woman was arrested on drug and alcohol charges shortly after midnight Tuesday after police spotted a car being driven erratically on the Stony Creek Bridge.

Police said a patrol officer spotted a 1987 Plymouth Reliant swerving to the shoulder, then back to the yellow center line as the car crossed the bridge. The officer followed the car to the intersection of Granada and Green Spring roads, where he pulled it over.

Police gave the driver a field sobriety test. She was then taken to the Eastern District station and searched. Police said they found two bags of a powdery white substance that tested positive for cocaine.

The cocaine was packaged for sale, said police, who also seized $150.

Joanne Marie Recktenwald of the 2500 block of Linwood Road was charged with driving while intoxicated and with drug violations, police said.