Charges have been laid after attempts were made to remove a woman sitting in the middle of the road on London Line on Saturday.
Police initially escorted a female from a motel property without significant incident but later, while still in the area, heard the same woman yelling and screaming as she left an area coffee shop.
Police said the woman then sat down in the middle of the road drinking her coffee, causing vehicles to slow down and swerve to avoid hitting her.
The woman allegedly elbowed the arresting officer and threw coffee at him before she was taken into custody, and later spat at an officer and struck him in the face.
A 25-year-old Sarnia woman faces charges of causing a disturbance, resisting arrest, and assaulting a peace officer.
She was in custody awaiting a bail hearing.