Before the Flashing Yellow Arrow (FYA)

The animation below, from Kittelson & Assoc, allows you to see an aerial view of traffic with a traditional 5-section left turn signal. Note that the northbound white car gets stuck in the intersection and, after misjudging the oncoming traffic, is struck at an angle. 

 

After the Flashing Yellow Arrow (FYA)

This next animation, also from Kittelson, allows you to see the same view of traffic with a new 4-section signal that includes the flashing yellow arrow (FYA). In this video, the northbound yellow car proceeds safely on the green arrow.  Later, the northbound white car is reminded by the flashing yellow arrow that it does not have the right-of-way and should yield to oncoming traffic.