Traffic Signals

To report a traffic signal outage during normal business hours, contact the Public Works Department at 972-292-5800. After hours, please call the Police Department at 972-292-6010.

To report a concern regarding traffic signal timing, please contact the Engineering Services Department at 972-292-5400.

Traffic Signals on SH 121 are under the jurisdiction of the City of Plano. Please contact the City of Plano at 972-941-7000 to report problems or concerns.

The Transportation Division continually evaluates each current and proposed signalized intersection to determine the safest and most efficient mode of operation based on standards specified by the Texas Manual on Uniform Traffic Control Devices. Even after a traffic signal is installed, all of the potential concerns at an intersection may not be addressed. For example, Dallas Parkway, south of Main Street, carries as many as 10 times more vehicles than the streets that it intersects. Because of this large imbalance in traffic volumes, motorists on the intersecting streets may experience long waits at the signals to keep the traffic on Dallas Parkway flowing at an acceptable rate.

Watch a Progress in Motion video on new traffic signals in Frisco.

Left Turn Signals

A left turn can be one of the most challenging actions a driver undertakes. In 2009 the flashing yellow arrow became the new national standard for displaying a permitted left turn. 

National researchers tested various methods of communicating how to make a permitted left turn. Studies show that drivers are less likely to make an unsafe decision when turning left using a flashing yellow arrow. 

Flashing yellow arrow signals provide multiple benefits. They keep traffic moving by offering drivers more opportunities to make left turns. Wait times and driver delays are reduced. Improved traffic flow at intersections reduces fuel consumption and vehicle emissions, which is better for the environment.

Left Turn Signal Graphic

Red Arrow

STOP! No left turn allowed. Drivers must stop.

Yellow Arrow

CAUTION! A steady yellow arrow warns drivers the light is about to change to red. Prepare to stop.

Flashing Yellow Arrow

YIELD! A flashing yellow arrow allows drivers to turn left after yielding the right-of-way to oncoming traffic and pedestrians. Oncoming traffic has a green light. Wait for a safe gap in traffic before turning. Yield first. Turn left with caution.

Green Arrow

GO! Drivers in the left turn lane have a protected left turn. It is safe to proceed with the left turn. Oncoming traffic has a red light.

Educational Resources

Flashing Yellow Arrow Flyer (PDF)
Texas Department of Transportation
Traffic signs and signals in Frisco (PDF)