Work zone intelligent transportation systems

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.

Key characteristics




WSDOT regions

Other names

  • Smart work zones
  • Work zone technology

Strategy description

Using Intelligent Transportation Systems (ITS) in work zones can improve the safety and mobility in and around transportation-project construction zones. ITS includes the use of electronics, computers, and communications equipment to collect and process information. It then uses the information to make decisions about how to manage the work zone.

ITS technologies are used in work zones for a variety of purposes, for example:

Traveler information

It is critical for the public to have accurate, up-to-date information about construction projects. Agencies can provide traveler information using message boards on the roadway, or online through websites and apps. Inaccurate information can result in increased congestion and other traffic issues, and those involved can lose confidence in future communication after a confusing experience navigating a work zone.

Incident detection and response

Managing incidents is important in work zones, especially when the project requires a lane reduction. If an incident restricts traffic even further, it can result in major congestion and delays. Agencies can install additional, portable cameras and communication devices to send extra information to a centralized location where agency staff monitor and respond to traffic demands and incidents in real-time, called a traffic management center. This is especially useful if the work zone is taking place in a location not covered by another camera monitoring setup. Include work zones in your traffic incident management (TIM) coordination plans and TIM operations

Dynamic lane merge 

ITS work zone systems maintain safety and traffic flow using dynamic lane merge systems. In this system, large, changeable message signs provide one of two messages, based on the conditions of highway traffic flow:

  1. If traffic is flowing freely, then the system directs motorists to merge early into a single lane before they enter the work zone. This maintains efficiency since vehicles can merge without conflict with one another.
  2. If traffic is congested, then the system changes the signs to direct motorists to stay in two lanes as they approach the work zone. Then another sign tells them to take turns merging into one lane—called a zipper merge—to enter the work zone. This keeps the vehicle queue shorter and has also been shown to reduce collisions.

Alert systems for workers

Systems should constantly monitor the protected work area using cameras or radar. If a vehicle encroaches into the work area, the system alerts all workers using a horn and/or on-person alarms so they are aware of the potential danger.

Speed management

Work zones can enforce reduced speeds using photo and video cameras with automated speed limit enforcement. Violators are identified by the system, the incident is verified by a law enforcement officer, and the system sends a citation in the mail to the vehicle owner.

Tracking performance-based contracting metrics

Metrics allow agencies to monitor work zone progress and its effects on roadway conditions with incentives or disincentives in the contract. For example, a contractor may receive a financial bonus each day they are off the roadway before 6:00AM, prior to morning peak hour commute. Alternatively, a contractor may receive a financial disincentive each day they are not off the roadway by a certain time. ITS tools support the accuracy of these measurements to ensure fair treatment of contractors and agencies.

Smart Technologies

  • To improve safety and efficiency in work zones, Queue Warning Systems (QWS), and Smart Work Zone Systems (SWZS) are being deployed in projects with anticipated work zone congestion. These systems use wireless technologies and web-based applications so roadside traffic sensors that detect reduced speeds, indicating the formation of queues, can trigger real-time warnings to drivers through a series of changeable message signs approaching the work zone. This allows drivers to adjust their speed accordingly before they reach congestion. With additional sensors, travel time delay information may also be provided and to help reduce the queue lengths, zipper merge messaging may also be displayed near lane closures if present.
  • Real-time work zone activity information is provided from arrow boards retrofitted with GPS and communications equipment. The status and position of a smart arrow board is broadcasted via a nationally recognized specification to traveler information systems or navigation applications as a source of confirmed information regarding the presence of lane closures and actions for drivers to take as they approach a work zone.
  • These systems and devices help improve safety for both drivers and workers by keeping drivers informed and helping them navigate the work zones safely and efficiently.

When to use this strategy

Work zone ITS technologies make sense for any work zone that is expected to have a significant impact on the roadway network. Each case is different, so agencies should follow their established policies and guidelines when choosing individual treatments.

Strategy benefits:

  • Reduces congestion caused by work zones
  • Improves safety in work zones for workers and road users
  • Increases the information that communities receive about work zones in their area

What you need in order to implement

Policy needs:

  • Agencies should have established policies for the use of ITS technologies in their work zones that are flexible enough to apply creative solutions. Each work zone is unique, so the policy must allow for different ITS applications.

Planning needs:

  • Each work zone ITS deployment should be preceded by an agency assessing its needs, identifying potential solutions, and analyzing feasibility before implementing

Coordination needs:

  • All stakeholders, including roadway agencies, contractors, and law enforcement, need to provide input into the goals and objectives of work zone ITS deployments

Equipment needs:

  • An extensive amount of equipment is required for ITS deployments, including computer software, detection devices (e.g., cameras, radar devices, in-pavement detectors, etc.), and communications systems to share the data

Maintenance needs:

  • ITS technologies in work zones are portable and need to be moved often. This requires additional maintenance of the equipment and continued testing to ensure that everything is working after each project phase and new work zone setup.

Agency resources needs:

  • Agencies need construction inspectors to ensure the work zone ITS devices are setup properly and being used appropriately. Staff at a traffic management center or office must receive data inputs from the system and use them for decision-making.

Learn more about this strategy

About key characteristics

Location notes:

ITS solutions are most often used in high-volume, urban roadways, but are sometimes also deployed in suburban and rural areas, depending on work zone and traveler needs.

Cost notes:

Costs are higher than traditional work zone devices (e.g., signs, cones, barrels, etc.), but ITS technologies can help agencies and contractors save money by speeding up the project and improving work zone safety.

Technology notes:

ITS devices in work zones are inherently technology-heavy, including detection equipment to collect data, communication devices to send it back to a central location, and software to process the data received.

Collaboration notes:

The most successful work zone ITS deployments include a wide range of stakeholders, including those responsible for incident management, law enforcement, and contractors completing the project work.