The overall goal of the study was to determine to what extent different vendors' traffic controllers can be effectively used in closed-loop signal systems in a manner acceptable to TxDOT engineers and maintenance personnel. Specific objectives to meet the goal included: Objective 1: Identify current practices and needs of TxDOT engineers and maintenance personnel. Objective 2: Define alternatives for providing closed-loop type traffc signal systems. Objective 3: Evaluate the feasibility and cost of implementing alternative system architectures for closed-loop traffic controller type systems. The findings of the work included a recommendation for TxDOT to proactively be involved in the National Transportation for ITS Protocol (NTCIP) and begin deployment of NTCIP compatible systems as soon as practical. The communications study also included a recommendation that TxDOT should actively be involved in the development of Advanced Transportation Controller standards, including controllers, cabinets, and software.