Low-Quality rendering of an Eagle Mark IV display. After several cycles the signals go into flash mode according to MUTCD guidelines. (Flash starts when the main street signal transitions from red to green) and comes out of flash mode also according to MUTCD guidelines (Start at main street green interval)
I have seen in Washington DC when the bottom yellow flashes....then it jumps to solid yellow on the middle....and to red......then back to flashing yellow in bottom
I've only seen R/Y/Y setups used at Midblock intersections (those intersections that just consist of a crosswalk so pedestrians can cross the street) Yellow flashing would replace green during the main phase in order to keep caution of pedestrians in the area.
Another place I see R/Y/Y is at firehouses. Once again, flashing yellow replaces green to indicate use caution around the firehouse.
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Another place I see R/Y/Y is at firehouses. Once again, flashing yellow replaces green to indicate use caution around the firehouse.