In 2006, FHWA issued an Interim Approval allowing states to display up to 12 LOGOs for a particular service on up to two sign panels. This provision, which was based on a study done by VDOT, has since been incorporated into the 2009 MUTCD.
Due to spacing constraints, and to minimize sign clutter, the MassDOT 2009 MUTCD Amendments restricts the total number of logos for a given service to six
QuoteSection 2J.04 Specific Service Signs - Number and Size of Signs and Logo Sign Panels
No more than six logo panels shall be provided for any service at a given interchange.
I'm curious as to what other states are currently allowing up to 12 logo panels at an interchange for a given service, and what states are restricting the number of logos to a maximum of 6.
I'm pretty sure I've seen exits in downstate Illinois that allow for 12 instances of the same service. However, they only fit 6 onto one sign--so you'll see two signs for the same service in anticipation of the same exit (6x2=12). I can't think of any examples off the top of my head though.
Arizona, for sure. Around here in the Phoenix area you regularly see two Food logo signs.
The Atlantic City Expressway has 2, 6 panel signs for food approaching Exit 41 (Cross Keys Road). Currently, I believe 10 restaurants have logos; 6 on one, and 4 on the other.