Traffic signs provide critical instructions to motorists, pedestrians, and cyclists. Signs are placed along, or above roads and highways, to guide, warn and regulate the safe flow of traffic. Scottsdale, like all cities in the nation, adheres to the Manual on Uniform Traffic Control Devices (MUTCD). Use of these standards provide uniformity in transportation and driver recognition and understanding of signage.

Multiway Stop Intersections

A stop sign is used at an intersection to assist drivers and pedestrians in determining who has the right-of-way. Multiway stop signs are used at intersections when traffic volumes on all approaches are approximately equal and at intersections where safety is a concern. The decision to install a multiway stop is based on an engineering study with considerations that include traffic volumes and collision history. Multiway stops are not to be used for speed control or to arbitrarily interrupt traffic.

Traffic signals are valuable devices for the control of vehicle and pedestrian traffic. Because they assign the right-of-way to the various traffic movements, signals have a profound influence on traffic flow. When property located and operated, signals may reduce the frequency of collisions, provide for the orderly movement of traffic, and increase the traffic-handling capacity of an intersection.

Traffic Signal Requirements

The Federal Highway Administration developed nine traffic signal warrants contained in the Manual on Uniform Traffic Control Devices (MUTCD). These warrants, or requirements, define the minimum conditions under which a signal may be justified; the manual states that traffic signals should not be installed unless one or more of the signal warrants are satisfied. However, the satisfaction of a warrant or warrants is not justification for a signal. Each situation is unique and must be analyzed on a case-by-case basis.

Flashing Yellow Left Turn Traffic Signals

Flashing yellow arrow traffic signals feature a flashing yellow arrow in addition to the standard red, yellow and green arrows. When illuminated the flashing yellow arrow allows motorists to make a left-hand turn after yielding to oncoming vehicles and pedestrians. Other than that, the signal works the same as a traditional signal.

Flashing Yellow Turn Signals operate as follows:

• Steady red arrow = Stop (no left turns allowed)
• Steady yellow arrow = Prepare to stop
• Flashing yellow arrow = Left turns allowed, vehicles must yield to oncoming traffic
• Steady green arrow = Left turns allowed

The use of flashing yellow left-turn arrows is the result of extensive research sponsored by the National Cooperative Highway Research Program. The research showed the flashing left-turn arrow was the most easily understood indication for drivers and is widely accepted in the traffic engineering industry.