Signal Platoon Patterns by Approach Lane use and Movement Class

The modelling of signal platoon patterns is further enhanced by using the Movement Class facility of the SIDRA INTERSECTION software. This is implemented by assigning two types of movements negotiating the network to Special Movement Classes, namely; (i) Through movements at external approaches which become turning movements at downstream internal approaches, and (ii) dogleg movements at staggered T intersections. These movements can be assigned to separate lanes and separate signal phases, and their arrival and departure flow patterns (second-by-second platoon patterns) including lane changes determined by the program can be tracked through the paired intersection system separately. This improves the quality of signal platoon modelling, and is expected to produce better results in assessing signal coordination quality and optimising signal offsets. The use of Special Movement Classes also helps to estimate unequal lane use cases at external approaches of a paired intersection system, a factor which also affects signal platoon patterns. A variation to the staggered T-intersection example included in the 26th ARRB Conference paper (Akçelik 2014) is presented to demonstrate the difference in performance estimates obtained with and without the use of Special Movement Classes.