Fig. 2
From: The traffic signal control problem for intersections: a review
![Fig. 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12544-020-00440-8/MediaObjects/12544_2020_440_Fig2_HTML.png)
Typical example of a signal phase sequence (NEMA ring-and-barrier diagram) in the United States [11]
An Open Access Journal
From: The traffic signal control problem for intersections: a review
Typical example of a signal phase sequence (NEMA ring-and-barrier diagram) in the United States [11]