Evaluation of actuated control of diamond interchanges with advanced experimental design.

Two three-phase actuated control strategies at diamond interchanges were investigated for different ramp spacings and traffic patterns. An advanced experimental design, hardware-in-the-loop control, was employed for the simulation study. Operational performance was identified in terms of cycle length, average delay and total stops. Experimental results showed that the two phasing strategies gave similar performance in terms of cycle length and average delay, but not stops. The cycle length of three-phase operation increased slightly as the ramp spacing became wider. The delay of each strategy was dependent on the traffic pattern, but there was a distinct movement preference for each strategy. The total stops decreased as the spacing increased, and it was the most sensitive variable for the studied traffic demand level. It was also shown that the concept of the hardware-in-the-loop control provides an effective way to evaluate the signal phasing and control strategies. [ABSTRACT FROM AUTHOR]