Traffic School
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What Are Traffic Lights?

The flow of traffic through intersections is regulated by traffic lights.  The most common type of light will have a red light on top, yellow light in the middle and green light at the bottom. 

  • A red light means stop.  You must come to a complete stop before the stop line, crosswalk or intersection.  When the light changes to green and the intersection is clear then you can proceed.  If the red light is flashing, you still must come to a complete stop.  In this case, yield to the cross traffic or pedestrians and then proceed.  If there is a red arrow then it means that you cannot turn in the direction of the arrow.
  • A yellow light means caution. This light cautions you that the signal is about to turn red and you will need to stop.  If you are already in the intersection then proceed through.  If you have not entered the intersection yet then you should come to a safe stop.  You should never speed up to ‘beat the light’.  This is how many accidents occur.  If the light is flashing yellow then you should slow down and look carefully for hazards and proceed if it is clear.
  • A green light means go.  You can proceed if the light is green.  Always proceed through an intersection with caution because other motorists or pedestrians may not be looking at the light.  If there is a green arrow then you can proceed in the direction the arrow is pointing.  When the arrow is lit, the oncoming traffic is required to stop.


The state of Idaho has implemented new types of traffic signals called “Dog House” Signals to improve the traffic flow at major intersections.  The “Dog House” signal is added to the regular traffic light and displays 5 lights instead of 3.  The additional lights are a yellow and green arrow to indicate a left turn.  The newest style of “Dog House” signals contains an additional yellow arrow instead of the green ball in the lower right side of the signal.  This indicates that the driver must yield to oncoming traffic and pedestrians before turning.  The purpose of the signals is to allow more vehicles to make left turns at intersections and keep the traffic moving. If a traffic signal is not functioning, the intersection should be treated as a four-way stop.

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