Intelligent Transportation Systems (ITS) Operations

Variable speed limits in action on westbound SR 520 in Bellevue. The right lane is the HOV lane which can display a different speed than the general purpose lanes depending on traffic conditions.

What is Intelligent Transportation Systems?

Intelligent Transportation Systems (ITS) is the technology that supports the operations of our state highway system. This technology is supported by communications systems which include wireless radio, Bluetooth and Wi-Fi, microwave systems and fiber optics. ITS and the supporting communication systems allow us to monitor and manage the roadways from our regional Traffic Management Centers (TMC). And it provides traveler information to those using our roads.

ITS technologies lay the groundwork for Transportations Systems Management and Operations (TSMO). TSMO encompasses the day-to-day actions and agency responses to the region's transportation system. TSMO strategies provide money-saving, multimodal solutions that relieve congestion, optimize infrastructure investments, promote travel options and reduce greenhouse gas emissions.

Image of VMS Border Wait Sign
Example of a VMS sign-displaying border wait times

ITS elements include:

  • Active Traffic Management (ATM) – ATM is the newest technology in our congestion relief program. It allows for improved safety and mobility during incidents, roadwork and peak commute times, without the need for costly roadway expansion.
  • Traffic Cameras (CCTV)   - We operate an extensive network of closed-circuit television across the state to help our TMCs detect and quickly respond to congestion, incidents and other problems on the roads. The camera images are sent, to the Web for travelers, to the media and Washington State Patrol (WSP).
  • Variable Message Signs (VMS)  - These are electronic signs used to provide travelers with information about traffic congestion, incidents, roadwork, travel times, special events or speed limits on the highway. They may also recommend alternative routes, weather related travel problems, emergency and disaster information, public service announcements and alerts (AMBER, Blue and Silver).
  • Highway Advisory Radios (HAR)   - HARs are licensed low-power AM radio stations installed along the roadway, which supplement the VMSs and 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 a specific AM frequency".
  • Road/Weather Information Systems (RWIS)   - RWIS stations are installed along the roadway with instruments and equipment, which provide weather and road surface condition observations. We use this information to help with decisions on maintenance strategies and to provide information to drivers. These stations may measure air and road surface temperature, barometric pressure, humidity, wind speed and direction, precipitation, visibility and road surface condition (dry, wet, freezing, etc.).
  • Ramp Meters - Ramp meters are traffic signals on freeway on-ramps that alternate between red and green to control the flow of vehicles entering the freeway mainline. Metering rates are adjusted automatically by the system based on prevailing freeway traffic conditions. Ramp meters balance out the flow of traffic entering the freeway, which helps reduce congestion and increase safety.
  • 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 we use 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, and Bluetooth. The detection data is used to operate traffic signals, ramp meters and travel time signs; and is sent from the roadside to the TMCs to monitor operations and provide traffic conditions to the website  and the WSDOT 511 traffic information hotline.
  • Traffic Management Centers (TMC) - WSDOT operates six regional TMCs . They are the nerve centers for our operations activities. Real-time information and data is gathered 24 hours a day, 7 days a week from many sources including traffic detectors, CCTV cameras, ramp meters and through communications with WSP, road crews, WSDOT's incident response teams  and media traffic reporters. We use this information to respond to incidents, deal with other problems that occur, and notify the public and the media of what is happening on the roads.

    We have six TMCs  that are located in Shoreline, Tacoma, Vancouver, Wenatchee, Yakima and Spokane. Each varies in capabilities and size to meet regional travel and operational needs. The centers in Tacoma, Vancouver and Spokane are co-located with other operating agencies. We also have a winter operations center on Snoqualmie Pass that manages travel across the pass during difficult weather conditions.

Key ITS Operations Offices

  • ITS Communications and Wireless Technology Office  - This group provides communications system planning, analysis and design which support our ITS systems, the TMCs and our workers on the road. The ITS Communications & Wireless Technology office also provides site, project and asset management.
  • Commercial Vehicle Services Office - This office provides services to commercial vehicle operators across the state and includes the Motor Carrier Services Group and the Commercial Vehicle Information Systems & Networks (CVISN) group. This group provides permits for freight movement and works with WSP to support enforcement of trucking regulations.
  • ITS Field Operations - This group works to provide coordinated operations of our TMCs and oversees the operations of our statewide This group works to provide coordinated operations of our TMCs and oversees the operations of our statewide Incident Response program. It also coordinates our Alert (AMBER, Silver and Blue) activities , manages the 511 traveler information system and the system that provides statewide traffic information on the website.