ITE, with its partner standards development organizations (AASHTO, NEMA and SAE International), with support from supported by the USDOT ITS Joint Program Office (JPO), developed an Implementation Guide to define key capabilities and interfaces a Connected Intersection (CI) as an infrastructure system that broadcasts signal, phase and timing (SPaT), mapping information and position correction data to vehicles. The CI Guide was the first CAV Standard developed by this group of SDO's with support from membership of IEEE as well. This presentation presents both the highlights of how this collaborative effort came to fruition as well as challenges that were overcome to ensure interoperability of systems for state and local infrastructure owner/operators (IOO) as well as communication with mobile devices. Several nodal agencies within USDOT were engaged in provided safety, fleet, trucking and pedestrian interests are safeguarded as well as in providing resources as needed to help an implementation ready product within two years. The CI Project has established an open dialogue between the IOOs, OEMs and the signal controller industry to develop a CI Implementation Guide. The result: interoperable connected intersections that enable safety applications to be developed for production vehicles. © 2000-2011 IEEE.