Sonic Corp. executives said they are developing a loyalty program to help drive traffic for the brand. Advertising shifts have helped drive sales, said Clifford Hudson, Sonic’s chairman and chief executive. “As we've noted beginning in January 2013, approximately 70% of our media dollars will be invested in national cable, with the remaining portion in local television and other mediums,” Hudson said, adding that the exposure should eventually have a positive impact on new-store development.