Last time I had my driver's license renewed, I noticed a bar code on the back.   So, I decided to try to read this bar code to see what kind of information might be hidden there.  Alabama allows you to refuse to put your social security number on the front of the license, and I was particularly interested in finding out if they had secretly encoded it in the bar code.

There are several different types of bar codes.  There are 1-dimensional codes, like the familiar UPC code found on food products.  The code used on the Alabama license is a 2-dimensional code of the format PDF417 (or PDF-417.)  The site BarCode 1.net has a lot of information about the various kinds of bar codes and how to read and write them.

PDF417 bar codes look like this.  (This isn't the one from my driver's license.)

I found some demo software from Axtel that will read the PDF417 from a TIF¹ image file.  Using a flat bed image scanner, I scanned the back of the license into a file, and decoded the bar codes into plain text.

Mike from Alabama writes that this site has an easy to use decoder that might work better than the one from Axtel.

The bar code contains 286 bytes of information.  The information is not encrypted and is delimited by short codes.  The file begins with the letters AAMVA, then includes several fields containing the personal information printed on the license.  There was no social security number, and no surprises.  (However, your state might be different.)    The only other information was some short codes at the beginning which indicate that the license came from Alabama, and is version number 1.

What could be the purpose for including all of this information in a barcode on the back of the license when they already have the information in the state database?  It must be there to communicate the information quickly to someone who is not connected to the database.  For example, police could quickly collect names, addresses and race of everyone passing a roadblock or boarding an airplane.  If you move to another state, it would save them a bit of typing.  

For them to make use of the information in the license itself, you have to give the license to them.  It would be far more useful to law enforcement if they could check everyone's ID without them being aware of it.  (See discussion of facial recognition below.)  The government might propose adding something to the license that can be queried via a low power radio transmitter (like shoplifting tags, or automatic toll collection schemes do now).

Paul from NY writes that the NY driver's license has both 1-D and 2-D barcodes.  The 1-D barcode contains the ID number, the birthdate and the expiration date.  Paul says that whenever he goes to a convenience store to buy beer, they scan his license using the IDentiScan IDS6000 which flashes red or green depending on age.  According to their site, the IDentiScan records the age, license number, date of birth and expiration date.  The information can later be uploaded to a host computer or printed.  Of course, the only information that they need to know is that you are over 21.  The unlikely rationale offered by IDentiScan is this: "Many bar, restaurant, and liquor store owners aren't aware of their state's legislation concerning the purchase of age sensitive products by a minor."  Since your personal information is stored, it could easily be combined with the cash register data and sold. The Pennsylvania Liquor Control Board (PLCB) requires a scan of your license at all liquor stores and the purchase information is kept in electronic database in Harrisburg for use by law enforcement.

Wired News reports that bars are using the scans to collect data on their customers.

David from Kansas writes that he used a reader to get the information from the magnetic strip on his license, and found that it duplicated the information printed on the front.

The AAMVA turns out to be an acronym for American Association of Motor Vehicle Administrators (their site).

The AAMVA National Standard for the DL/ID 2000 available here describes the bar code file format and all of the possible fields (including several which are not on my license).  It describes mapping drivers license information to magnetic tape, optical memory cards, and integrated circuits. 

Those other formats can hold a lot more data than a bar code, and would be much more difficult to read (or more likely will be encrypted.)  A binary file containing your photograph could easily be included in such a format. (Your state is probably already keeping a copy of your license photograph in a database in case you turn out to be a criminal.) But, most likely a chip in the license of the near future will store your fingerprint and you'll be required to touch a scanner to prove it's your card.

The Denver Post reports that driver's license photographs of innocent people have been routinely used in police photo lineups for over 30 years. If you are mistakenly identified as a criminal, a background check is run on you, and you may be interviewed by police and required to produce an alibi.

Hidden cameras and facial recognition software have been used at the Superbowl, and other public places.  The existing driver's license photographs, taken under controlled lighting conditions could allow everyone to be identified and whereabouts recorded in a database. (Update: It has been reported that some of the facial recognition software currently doesn't work very well in actual use.)

I'm sure that you'll be comforted knowing that the AAMVA is fulfilling its mission "to more effectively serve the driving public" by developing standards for the storage and exchange of facial, fingerprint and signature images. Recently the AAMVA has been behind efforts to integrate the driver's license information from each of the 50 states, creating in effect, a national ID card.

There are some interesting articles on the AAMVA site, including reprints from their Move Magazine:

A License to Sell (your driver's license information)
"Motor vehicle agencies have large databases, replete with information on
drivers, vehicles and other topics, that can be extremely attractive to other
agencies and private sector businesses. Driver files not only include
names, addresses and photos, but sometimes contain information on
convictions, medical conditions and other personal data that companies
may find useful for marketing. "

Biometrics - Identifying the Issue
"One of the advantages of driver's license systems is that they deal with cooperative
individuals (more or less), who can be instructed to assume fixed poses.
The environment in which the individuals' images are captured also can be
controlled, including lighting, distance of the capture device from the
subject, etc. This affords the opportunity to capture images that are as
consistent as possible, greatly aiding the comparison task."

Current and Ongoing Efforts - Biometrics
"AAMVA is very pleased to have had the opportunity to work through the biometric industry to develop the first ever minutiae extraction standard for finger imaging."

Biometrics Big Boon or Big Brother
"Motor vehicle administrators search for new ways to use promising
new technologies without trampling on customer beliefs."

Note that they say customer "beliefs", not "rights."

¹ TIF or TIFF, a file format for images.  It just happens to be the format that the demo program can read.  It took a little fooling around with the TIF file (inverting black and white) and trying some different TIF file options to find one that the software would read.