The flow of MOST gas station shops goes like this:
1. park at a pump, get gas
2. go inside evaluate a restroom
3. buy something inside
4. go back to your car, move it away from the pump
5. put on your vest, get your LOA and introduce yourself.
6. do the audit portion of the shop.
You can buy a traffic safety vest on Amazon for around $10. Or you can pay for a very expensive one for around $20.