Police caught up with her at 16th and Locust streets just before 9 p.m. Tuesday.
Investigators said a Streets Department pickup truck was idling at 12th and Walnut while crews were doing pothole repairs.
That's when, according to police, 33-year-old Amanda Bonner told workers "she had to pee" and was going to urinate in between their trucks. But police say she got into the vehicle and drove off.
"She did make a statement to police officers that she was high on drugs and she has no idea why she did that," Philadelphia Police Inspector Ray Evers said.
There were no injuries.
Bonner is facing theft charges.