In the United States, a driver's license number serves as a de facto identification document. It contains information about the driver's name, gender and date of birth. It also allows the driver to operate a vehicle legally.
The numbers are comprised of four digital codes separated by a hyphen. Each state has its own way of encoding numbers to the license. In some states, the first part is often a Soundex code for the last name, the second code is for the first and middle name, the third section is the year of birth and the fourth section is the driver's day and month of birth as well as his gender.