There a two types of controlled intersections, YIELD and STOP; you must come to a full stop at an ASMP sign, crosswalk or stop line. At a YIELD sign, slow and yield(wait for) the right of way vehicles on the through street.
As you drive towards a signal-controlled intersection you will need to consider if the signal is about to change. Searching 12-15 seconds ahead, evaluate the next intersection to see what color that light is. Look for any traffic moving on the cross street. Before you reach the point where you must brake at an intersection, quickly check your front zones. If you predict the light is going to be red, or if cross traffic has closed your frontal zone, check your rear zone and be prepared to stop.