Traffic Engineering > How Traffic Signals Work
- As traffic volumes increase beyond the capability of lesser controls such as a four-way stop, it may be necessary to install a traffic signal.
- Traffic signals are more costly than is commonly realized, even though they represent a sound public investment when justified. A modern signal can cost up to $250,000. This money pays for a Traffic signal controller, signal heads, vehicle detectors and signal poles and supports.
- Traffic Signal Preemption -The transfer of signal control to a special signal operation is called preemption. There are two common types of preemption, based on reason for preemption: Railroad and Emergency Vehicle. Signal poles and supports.
- Signal Timing - Along major arterials which have several traffic signals spaced at periodic intervals, the traffic signals are usually synchronized to provide coordinated movement along the major street. Traffic signals assign the right of way to various traffic movements for different time intervals depending on traffic flow levels. Pre-timed signals have pre-set time intervals for different times of the day including the morning, noon, and evening peak travel periods. The city has a few pre-timed signals remaining in the outlying areas which have not been connected to the central system. Traffic actuated signals use detectors on the approaches to traffic signals to monitor and assign the right of way on the basis of changing traffic demand. These signals attempt to assign most of the available green time to the heaviest traffic movements.
Traffic Engineering Division
Public Works Department
333 N. Rancho Drive
Las Vegas, NV 89106 (Map)
Phone: (702) 229-6327
Fax: (702) 366-0032
Business Hours: Monday to Thursday 7 a.m. to 5:30 p.m., CLOSED Friday