The mail truck coming from behind.

Anna was about halfway past the first house, with her arms wrapped tightly around her intimates. It felt good to apply pressure between her legs, but she shook her head.

'Maybe in the shower,' she thought. Her blush had grown a little brighter. To even think about doing something like that, outside on the sidewalk seemed crazy. Being naked outside was one thing, but to touch herself was another.

Then, she heard a sound coming from behind her. It was the distinct rumbling of a motor. Obviously it was some kind of car, but not just any car. The rumbling was loud, as if the muffler was failing. Anna looked back and confirmed her suspicions, it was a mail truck.

The naked girl turned her head away in disbelief, feeling her heart rate pick up. She was certain that there were no cars coming, where did the mail truck come from?

With no time to wonder, she had to get out of sight and quick.

The house she was passing right now had a car in the driveway she could hide behind, but the car simply being there meant somebody was home. Somebody that could see her.

The next house had some bushes she could hide behind, but they'd need a quick run. Possibly even a jump.

She could also have tried a full on sprint to her home. Anna had successfully outran the track team, so maybe she could run like that again. However, it was very likely the mailman would see her, just as the track team did.