Intelligent Transportation Systems
Refers to the integration of advanced communications technology in transportation infrastructure and vehicles to enhances mobility and safety across modes. ITS solutions are cost effective and can be quickly implemented when compared to traditional capacity improvements. ITS solutions can also collect data toward insights on safety and performance of the transportation network. Examples include changeable message signs notifying drivers of weather or congestion, road weather cameras so travelers can check their trip route before heading out, and smart work zone practices.
Active traffic management (ATM) includes a broad range of strategies for managing traffic dynamically based on current or expected conditions in order to improve the efficiency and safety of the transportation system. ATM strategies include ramp metering, variable speed limits, queue warning, and traveler information systems.
Adaptive signals change traffic signal timings based on current traffic conditions. Using hardware, adaptive signals measure the traffic conditions of vehicles, bicyclists, and pedestrians and then utilize software to make timing changes based on the real-time data.
Interagency coordination for corridor management refers to the methods and policies that enable participating agencies and jurisdictions to operate a corridor, or primary route, jointly and effectively.
Data helps drive decision making and measure the performance of transportation strategies. Agencies can source certain types of data from WSDOT, other agencies, and the private sector.
Dynamic lane assignment strategies repurpose road space based on current or expected demand conditions in order to improve the efficiency and safety of the transportation system. Dynamic lane assignment strategies include reversible lanes on highways and arterials, merge (or junction) control on highway ramps, and part-time highway shoulder use.
Emergency vehicle preemption (EVP) interrupts normal traffic signal timing to provide a green light to approaching emergency vehicles so that they can pass through intersections to get to emergencies safely and quickly.
Freight (or truck) signal priority (FSP) provides extra green light time so that a heavy truck can move through a traffic signal without stopping.
Highway advisory radio (HAR) transmits audio traveler information messages via radio to travelers within range of the signal. Roadside signs inform travelers of the radio frequency and often use flashing lights to alert travelers of advisory messages.
Intersection conflict and trail conflict warning systems are traffic control devices that provide road users with a real-time, dynamic warning of vehicles or pedestrians that are approaching or waiting to enter an intersection or crossing.
When a roadway detour to a parallel route is needed, it is necessary to communicate the detour clearly to travelers, as well as consider the transportation safety and efficiency needs on the parallel/detour route.
Planned event or incident signal timing synchronizes groups of traffic signals to favor traffic entering and exiting a special event venue or area in order to minimize congestion. It can also be used to divert traffic around an unplanned event, such as an incident or a regionwide evacuation.
Proactive signal timing review and optimization uses actual traffic performance data to operate and manage traffic signals. This strategy can help improve safety, reduce vehicle delays, and help more finely target maintenance activities.
Queue warnings inform drivers about stopped or slow traffic ahead to provide vehicles more time to slow down safely. Queue warning systems use real-time traffic detection to identify queues and roadside variable message signs (VMS) to display the warnings.
Ramp metering is an active traffic management (ATM) strategy that uses traffic signals at freeway on-ramps to control the number of vehicles entering the freeway to keep vehicles moving more efficiently.
Reversible lanes allow agencies to switch the direction of traffic flow during certain times and conditions. They are typically used during peak commuting hours to add capacity in one direction.
Road weather information systems (RWIS) monitor local roadway and weather condition information and alert an agency and the traveling public about inclement weather conditions. It can be highly customized to the specific weather conditions and detection needs of a given location.
Providing travelers with pre-trip and real-time information about travel times and potential delays can help them make alternate routing and timing decisions to avoid congestion.
Signal timing review and optimization synchronizes groups of traffic signals so that vehicles on a primary route can travel through multiple traffic signals without stopping. It can also reduce vehicle wait times at individual intersections by adjusting the length of green lights to match demand.
Traffic signals are an essential, cost-effective tool to manage the movement of traffic and provide solutions to a variety of mobility, safety, and system management goals. However, traffic signals are sometimes an unnecessary expense that can add to collisions, congestion, and delay.
Tolls can serve as an additional source of revenue to pay for highway or transit construction or operations costs. Toll revenue can also be used to repay long-term debt used to finance the construction of the transportation facility.
Traffic detectors are a critical part of any intelligent transportation system. They collect data about the current traffic conditions so that transportation management and operations decisions can be made.
Traffic management centers (TMCs) are the control centers where municipal or regional transportation operations are coordinated. They support agency coordination and collaboration by collecting various functions within a single location, which allows for a more holistic, system-wide management of regional transportation.
Traffic signal priority and preemption settings modify the traffic signal timing and give priority to specific vehicle types, such as buses, light rail, streetcars, trucks, emergency vehicles, or trains.
Transit signal priority (TSP) makes it more likely that the light is green when a transit vehicle reaches a signalized intersection. This strategy reduces travel times for transit vehicles by avoiding the need to stop and start at signalized intersections.
Traveler information services use personal, connected devices to provide travelers with real-time and customizable information that is relevant to their specific travel needs. This can include location-based information about delays, incidents, weather-related messages, travel times, emergency alerts, route guidance, and more.
Variable message signs (VMS) are electronic roadside signs used to post traveler information messages to inform drivers of incidents, travel times, detours, special events, and other useful road conditions or travel information.
Variable speed limits (VSL) is an active traffic management (ATM) strategy that uses dynamic speed limit signs to slow traffic before and through adverse conditions on the freeway to improve safety and keep traffic moving efficiently.
Weigh-in-motion (WIM) systems measure the weight of trucks while they are moving in order to identify which vehicles are overweight, so that weight overload penalties can be enforced. The underweight vehicles can bypass the weigh station, while overweight vehicles are directed to another location for additional weighing.
Intelligent Transportation Systems (ITS) in work zones encompass a broad range of technologies aimed at enhancing work zone safety and mobility. Strategies may include variable message signs, automated speed enforcement, incident management, providing traveler information, and more.
Wrong-way driver detection uses sensors on freeway off-ramps to detect vehicles driving in the wrong direction. The system alerts the driver of their mistake, warns nearby travelers, informs agency staff at a central traffic management center of the need to monitor the situation, and notifies law enforcement so that they can prevent a collision.