A radio ad you can read

Here's a radio ad created for Gandhi Bookstores from Mexico City that you can actually read:

In congested Mexico City, people spend hours sitting in traffic.  Using RDS systems that is used to identify stations and artist and tracks played, they transmitted a short message on commuters car radios.

Announcer:  If you are stuck in traffic look at your stereo's screen.  

Screen:  This advert promotes reading.  That's why you are reading it.  

Announcer:  Gandhi Bookstores.  Keep reading.