Implementing Actuated Control of Diamond Interchanges

The design of signal timings for diamond intersections is well documented in the literature, and there are a variety of software packages to assist one in generating timing plans. However, the actual implementation of diamond intersection control procedures on modern dual ring actuated controllers is not documented in the literature, primarily because early implementations used vendor specific features on modern controllers. Consequently, none of the implementation procedures were transferable. In recent years, vendors have greatly increased the flexibility of their traffic controllers and now provide configurable ring structures, overlaps, detector modes, and detector mapping. This paper synthesizes current practice and defines procedures for implementing both three-phase and four-phase diamond control logic using common features on modern traffic controllers. The procedures introduced in this paper should allow this important area to mature and gain widespread implementation, leading to more efficient traffic signal operation at signalized diamond interchanges.