Sure mattd.
The European lights go from green to yellow to red on one street then from red to yellow to green on the other street. When time is up it reverses the sequence.
The US lights go from green to yellow to red on one street then from red to green on the other street. Then the street that is currently green goes to yellow then red then the first street goes from red to green.
The US lights only use the yellow when they are in the process of changing red.
Hope this helps.... :-/
Dan