Critically comprehensive

June 5, 2017

Iowa’s Traffic Critical Projects program is a new take on work-zone management

The Traffic Critical Projects (TCP) program was started in 2014 by members of the Iowa Department of Transportation (IDOT) Offices of Traffic Operations and Traffic and Safety.

A call to action from department management prioritized safety and mobility within work zones leading to the identification of key construction projects requiring enhanced traffic-mitigation strategies, including the use of technology to provide dynamic and real-time information to drivers. Iowa solicited assistance from a regional consultant with knowledge and experience to assist in the new endeavor.

The IDOT TCP program has the primary goals of:

  • Identifying upcoming projects during the planning and design stages that have potential to cause significant safety or mobility impacts;
  • Applying various mitigation strategies to address potential safety or mobility concerns, including quick recovery from traffic incidents or queuing;
  • Evaluating mitigation efforts to determine if they are reliable, timely and effective;
  • Developing performance measures that can be used to establish safety goals and travel-time delay targets in Iowa, and applying performance measures to quantify the safety and mobility impacts of the program; and
  • Developing support throughout IDOT for the TCP program by establishing easily understood and implementable program procedures.

Iowa currently defines a Traffic Critical Project as any project causing significant delay or mobility and safety issues on interstates or multi-lane highways with speeds over 55 mph. If a project meets these criteria it is reviewed for means to lessen the impact on the traveling public. Acceptable design mitigations include: detour routing, limited construction hours (including night work or date/time restrictions), lane-rental contracting mechanisms, and traffic incident management (TIM). If the project cannot be redesigned or scheduled to mitigate mobility and safety concerns, an intelligent work zone (IWZ) is deployed on the project to help monitor and alert drivers of potential safety concerns.

How it’s different

TCP utilizes traffic-improvement strategies and works to help IDOT by reducing or eliminating potential safety or mobility concerns, reducing crashes, quickly recovering roadways after an incident, supplementing temporary traffic-control plans, and by meeting FHWA safety and mobility regulations. All levels of IDOT, from upper management to project staff, are responsible in some capacity for making sure that the program is successfully implemented. Outside support to perform critical tasks is provided from consultants, contractors and vendors as needed. Four teams were formed with defined meeting schedules, roles and responsibilities to manage the TCP program.

The Executive Committee is comprised of upper management within IDOT and provides support and guidance to the TCP program.

The Stakeholder Group includes department leads from across IDOT including design, bridge, construction, maintenance, operations and the FHWA. Members provide feedback and express any concerns with the program or any new policies/procedures. Members also bring information on the TCP program back to their respective offices to solicit more feedback.

The Working Group brings together people from the offices of traffic operations, construction and materials, traffic and safety, Iowa State University, and consultants. This group develops the policies and procedures to move the TCP program towards its goals and works to ensure continued support of the TCP program from all areas within IDOT.

The IWZ Team consists of people from the office of traffic operations, traffic management center staff, advanced traffic management system (ATMS) integrators, the IWZ vendor, Iowa State University and multiple consultants. This group meets on a weekly (or more frequent) basis during the construction season. In the winter months, the team will meet on an as-needed basis to support the efforts of the Working Group. These weekly meetings are teleconferences to best facilitate participation and are focused on managing the IWZ deployments across the state. The primary responsibility of the IWZ Team is to ensure all IWZ projects meet program goals and objectives, and to use the lessons learned each season to implement efficiencies and new ideas in subsequent programs. The IWZ team also maintains the program website ( which contains all program information on current and upcoming project locations and information on the public page. Team members are able to log in to view more sensitive information such as device location information, IP addresses, downed device logs and other pertinent information for the team.


Deploying IWZ on roadway construction is nothing new; transportation professionals have been deploying items such as cameras, sensors and dynamic message signs on roadway projects for some time now. In most cases, these systems are generally standalone or one-off deployments and are managed by the contractor. In rare instances, a select few are run by a DOT, county or city facility. Largely little or no evaluation is performed on IWZ deployments and typically any evaluation that is conducted is completed after project completion. Iowa had a different vision for its roadways.

Iowa developed its IWZ deployments with focus directed on four key standards:

  • All IWZ items would be compatible with the existing traffic-management software used by IDOT and accessible via 5-1-1;
  • All IWZ projects would be centrally managed, monitored and evaluated;
  • All TCP projects would be tracked so that if the need arose, further action could be taken; and
  • All IWZ devices would be procured from a single vendor.

Growing pains

Iowa released the RFP for its IWZ device needs in the spring of 2014. After a vendor was selected, the teams hit the ground running in an effort to get systems deployed on the first-year projects that had been identified by the Working Group. The first year the IWZ team deployed queue detection systems on 14 projects.

Projects were monitored by the consultant and the Center for Transportation Research and Education (CTRE) at Iowa State University on a 24-hour delay the first year to ensure all devices were communicating and performing as expected. While the first year was ultimately a success, there was room for improvement. Lessons learned in the first year included finding an alternate means to operate rural cameras to reduce large cellular data usage and how to best use GPS on devices (fun fact: if your device’s GPS resets itself, it will end up at (0,0) in the middle of the ocean).

The second year identified 58 projects that were classified as TCP, 27 of which would have IWZ devices. Marching forward with the 2014 lessons learned, the TCP team established clearly defined operating procedures and delineated the responsibilities for each team member for all practices, such as: IWZ deployment, integration, logic for queue detection, troubleshooting, maintenance, relocation and harvesting. Queue detection, curve warning and TIM planning were the most commonly deployed systems in 2015.

Evaluation of deployed intelligent work zones was a priority in 2015. CTRE developed a tool capable of near real-time monitoring of each work zone using raw data feeds from Iowa’s traffic management software and additional data from a third-party vendor. The most prominent lesson learned in the second year was that all permanent devices used for IWZ deployments needed to be checked for communication and calibration if they are to be used within an IWZ system. Additionally the performance of permanent devices needed to be monitored and held to the same standard of functionality as the portable devices provided by the vendor. The weekly conference calls with the IWZ team facilitated rapid response times to fixed downed devices.

In 2016, the TCP program saw its third year of implementation. The program tracked 64 traffic-critical projects and deployed IWZ devices on 34 projects throughout the state. In addition to the IWZ systems used in previous years, a dynamic truck-entering system and a merge-warning system also were deployed this year. Performing pre-checks on all of the permanent devices planned to be used for IWZ and early determination of availability of radio connections versus cellular modem (rural) camera needs made for a significant decrease in the turnaround time of deployment of devices to working IWZ systems. The program is currently identifying lessons learned from 2016, greatly facilitated by the IWZ end-of-season closeout workshop, where IWZ team members come together to discuss the previous season. Some preliminary recommendations from this season will be working towards better outreach and communication with the on-site project staff, ultimately the project inspectors (and all project crew members).

Moving forward

The ultimate goal for the Iowa TCP program is to make the TCP initiative a self-sustaining program. The necessary procedural and formal documentation necessary to institutionalize the TCP program are in the process of being finalized. This includes: new DOT policies, formal procedural guidelines and a refined quality management plan. The formal documentation and its implementation will shape and guide the TCP program into a highly successful and efficient process that will become standard practice in future project planning design and deployment.

This program is working with designers, districts and FHWA so that appropriate levels of reporting are established, and mitigations meet all state and federal requirements. More importantly, the program teams are working diligently to ensure IDOT is meeting the needs of its most important customers—the traveling public.

About The Author: Falero is an engineer with SRF.

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