Traffic Lights

Traffic lights, also known as traffic signals, signal lights, and stop lights, and also known technically as traffic control signals, are signaling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic.

Other forms of traffic lighting, such as flashing beacons and speed radars, can be used to warn motorists of changing road conditions, presence of pedestrians, or to signal reduced speed.

Types of Traffic Lighting

Signalized Intersections

Signalized intersections control competing flows of traffic by alternating the right-of-way accorded to drivers and pedestrians. This is done by displaying lights of a standard color code: red indicating STOP, green indicating GO, and yellow indicating PREPARE TO STOP, for those who are still approaching the intersection.

Flashing Red Beacons

A flashing red light is the same as a stop sign. These indicate that vehicles must come to a full stop before proceeding further.

Flashing Yellow Beacons

A flashing yellow light indicates that drivers are required to slow down and proceed with extreme caution. These may be used when there is an oncoming change in road conditions, such as a sharp turn, narrowing road, or a stop.

Radar Speed Signs

A radar speed sign is an interactive electronic sign that displays speed as motorists approach. Often the display will flash rapidly if the vehicle is exceeding the speed limit.

Contact Information

Business Hours
Monday – Friday
8:00 AM – 5:00 PM

By Appointment Only.  Responding 24x7 to Emergencies.

Contact us by Phone
Office Location
La Plaza B
2300 County Center Drive
Suite B 100
Santa Rosa, CA 95403
38.462023, -122.725381


Manual for Uniform Traffic Control Devices


Find out about standard design and placement requirements for traffic control infrastructure.