Traffic Signals

To report a traffic signal outage during normal business hours, contact the Public Works Department at 972-292-5800. At other times, 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.

Types of Traffic Signs & Signals 

Flashing Yellow Arrow

Left turns are permitted.  Drivers must YIELD to oncoming traffic and pedestrians before turning. Oncoming traffic has a green light. Wait for a safe gap in traffic before turning. 

Flashing yellow arrows are a fairly new standard for left turn signals. According to a national study, flashing yellow arrow left turns are more easily understood by drivers than traditional yield-on-green indicators. 

Steady Green Arrow

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.

Steady Red Arrow

Drivers must stop.

Read more about Flashing Yellow Arrows
Texas Department of Transportation
Traffic signs and signals in Frisco (PDF)