They are scanning the PDF 417 barcode on the back.

Here are the specs for what appears on the driving license/ID and how to read the barcode:

https://www.aamva.org/getmedia/99ac7057-0f4d-4461-b0a2-3a553...

They issue a new spec every 4 years.

Thank you!

After a while you age out of getting carded. The vast majority of alcohol is bought without ever showing any ID.

I aged out of getting carded a long time ago, but I'm seeing stores where their policy is to card everyone. I was behind an old man with white hair and a cane who was bewildered when he was carded.

Stores collect not required customer information often.