Clarke told the Herald she was well and truly within the white lines, but found the incident humorous.
"It was a narrow space that I reversed three times to leave space on either side and was within the white lines.
"I thought it was advertising at first. The card was popped inside my driver's window facing inwards.
"I was just more surprised someone had typed cards on hand waiting for someone to cross them.
"No one has ever called me an a**hole before so I thought that was quite empowering and funny.
"I do have a nice new work car so they might have been a bit annoyed about that, too."
Despite seeing the funny side, a number of Jo's friends have hit out at the person who left the vile message.
One person said: "If someone has gone to all the trouble to make these then they should seek help!"
Another wrote: "I can't believe people actually go to that trouble ... must be some real pent up anger inside them."
It is not known who placed the abusive card on the car.