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Intelligent Transportation Systems (ITS) Operations
What is Intelligent Transportation Systems?
Running parallel to virtually our entire state highway network there is a less visible but very important technology infrastructure. This technology infrastructure is typically referred to as Intelligent Transportation Systems or ITS.
Key ITS elements include:
- Communications Backbone - The backbone of ITS is communications. Washington State Department of Transportation (WSDOT) operates a communication system composed of radio, microwave and fiber optics elements that touches all sections of the road network. It provides radio communications for those maintaining the roads and data transmission for those managing the roads. The data that is transmitted over the system comes rom many ITS elements that are part of our overall traffic management efforts.
- Traffic Cameras (CCTV) - WSDOT operates an extensive network of closed-circuit television across the state to help detect congestion and accidents, and to be constantly aware of traffic and road conditions. The camera images are sent to our traffic management centers for operations monitoring, to the web for travelers, and to the media.
- Variable Message Signs (VMS) - A variable message sign is an electronic traffic sign used on roadways to provide motorist with important information about traffic congestion, incidents, roadwork zones, travel times, special events, or speed limits on a specific highway segment. They may also recommend alternative routes, limit travel speed, warn of duration and location of problem, or simply provide alerts or warnings.
- Highway Advisory Radios (HAR) - Highway advisory radio are licensed low-power AM radio stations installed along the roadway to provide alerts and general information regarding traffic and travel. The presence of a HAR transmitter is marked by a roadway sign instructing motorist to "Tune to 1610 AM". The 1610 frequency is one of several used by HAR radios and identified on the signs.
- Road/Weather Information Systems (RWIS) - Road/weather Information Systems are installed along the roadway with instruments and equipment which provide weather and road surface condition observations. This information is used to facilitate decisions on maintenance strategies and to provide information to drivers.
A typical RWIS station may measure air and road surface temperature, barometric pressure, humidity, wind speed and direction, precipitation, visibility and road surface condition (dry, wet, freezing).
- Ramp Meters - Ramp meters are traffic signals on freeway on-ramps which alternate between red and green to control the flow of vehicles entering the freeway mainline. Metering rates are automatically adjusted by the system based on prevailing freeway traffic conditions.
- Traffic Data Collectors - Traffic detectors are one of the key set of tools used to keep track of what is happening on the roadways. The most common detector WSDOT uses is the induction loop, a simple low-voltage wire coil buried in the roadway that sends an electrical pulse when a vehicle passes over it. Other, less common detectors use infrared, radar, sound, or video imaging to detect vehicles. The detection data is sent from the roadside to WSDOT traffic management centers to monitor operations and provide traffic conditions to the web and the WSDOT 511 traffic information hotline.
- Traffic Management Centers (TMC) - WSDOT operates seven regional Traffic Management Centers (TMC). They are the nerve centers for WSDOT's operations activities. Real-time information is gathered 24 hours a day, 7 days a week from many sources including traffic detectors, CCTV cameras, ramp meters, the Washington State Patrol (WSP), road crews, WSDOT's incident response teams, and media traffic reporters. WSDOT uses this information to coordinate responses to clear accidents, deal with other problems that occur, and notify the public and the media of these events.
WSDOT's seven Traffic Management Centers are located in Shoreline, Tacoma, Bellingham, Vancouver, Yakima, and Wenatchee. Each varies in capabilities and is sized to meet regional needs. The centers in Tacoma, Vancouver, Spokane, and Yakima are co-located with other operating agencies. WSDOT also has a winter operations center on Snoqualmie Pass.
Key ITS Operations Offices:
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