IN THIS CASE STUDY YOU WILL LEARN:
- How Iowa DOT developed a detailed, five-year Work Zone Management Service Layer Plan to clarify the tactical areas in which the Department should apply its limited time and resources.
- How the plan incorporates resources for determining Traffic Critical Projects (TCP) and provide resources for mitigation countermeasures that integrated into the project Design Manual
- How Iowa DOT successfully monitors and provides feedback using Real- time Performance Monitoring, Flex- Enforcement, Smart Arrow Boards, and Iowa Work Zone Data Hub, a Work Zone Council, Annual Work Zone Safety Awards and Improved Data Driven Work Zone Process Review Procedures
Iowa, the crossroads of America’s Heartland, is an essential link in the country’s transportation network, with Interstates 35 and 80 crisscrossing the state. A recent report by TRIP, a national transportation research nonprofit, forecasts freight moved by trucks in Iowa will increase 53 percent (by value) from 2016 to 2045. Managing Interstate and other critical regional connections to meet the needs of existing and projected freight growth has challenged the Iowa Department of Transportation (Iowa DOT) to focus on minimizing the delays and improving safety associated with highway construction.
The Iowa Department of Transportation (DOT)’s 2016 Transportation Systems Management and Operations (TSMO) Strategic and Program Plans reinforced the Department’s need to focus on proactive work zone management as one of eight critical areas. In conjunction with SRF Consulting Group, thethe Iowa DOT developed a detailed, five-year Work Zone Management Service Layer Plan to clarify the tactical areas in which the Department should apply its limited time and resources. The plan elevated the importance of work- zone management throughout the DOT, resulting in a number of crucial activities, all of which contribute to improving safety, the effects of delays, and the DOT’s TSMO maturity.
TSMO Planning, Strategies and Deployment
To determine which types of highway projects require additional work z one management attention, the Traffic Critical Projects (TCP) process was developed and integrated into the Department’s Design Manual in March 2019. The two- step process determines, 1) Does the proposed work qualify as a TCP, and 2) Is the project designated as Significant, which requires an added level of planning. The criteria to determine whether a project is categorized as TCP or Significant:
- Primary Highway System
- High Speed Multi- Lane Highway
- Work within 15’ of Edge of Slab
- AADT over 15,000 or 11,000 w/ 20% trucks
- Lane Closure Planning Tool (Figure 1) shows proposed work exceeds capacity
- Located within a Metropolitan Planning Organization (MPO) or Transportation Management Areas (TMA) Des Moines, Quad Cities or Council Bluffs
- On an Interstate
- Lane closure lasting more than three days
An online checklist has been developed to verify the mitigation measures that will be integrated into the TCP. A newly developed Work Zone Reference Library also houses a consolidated collection of practitioner resources.
- Lane Closure Planning Tool: https://secure.iowadot.gov/lcptool/Index.aspx
- Online TCP Checklist: https://webapps.srfconsulting.com/idottcp/
- TCP Section of Design Manual: https://iowadot.gov/design/dmanual/09e-01.pdf
- Work Zone Reference Library: https://iowadot.gov/workzonereferencelibrary
Based on outcomes of the TCP process checklist, several mitigation countermeasures are integrated into the project Design Manual including:
- Traffic Operations Treatments (https://iowadot.gov/design/dmanual/09f- 06.pdf ) – Options include extra enforcement, contractor ingress/egress requirements, maximum allowable delay specifications to minimize backups, detours during full closure, and contraflow operations to manage peak traffic volumes.
- Intelligent Work Zone (IWZ) Equipment (https://iowadot.gov/design/dmanual/09f- 07.pdf ) – Iowa DOT is an early adopter in requiring all IWZ equipment to seamlessly integrate with the statewide TMC’s advanced traffic management system (ATMS). TMC operators can visually monitor permanent field equipment and temporary IWZ equipment simultaneously. The program has grown from 20 TCP with 14 Intelligent Work Zone projects in 2014 to 75 TCP and 46 Intelligent Work Zone projects in 2020. A variety of IWZ solutions are employed, depending on specific needs:
- End- of- Queue Warning
- Monitoring Sensors
- Speed Feedback Signs
- Dynamic Truck Entering Traffic Warning System
- Portable DMS with Radar Warnings
- Travel Time Systems (including alternate routes)
- Work Zone Traffic Incident Management (TIM) Plans (https://iowadot.gov/design/dmanual/09f- 08.pdf ) - Most TCP locations, including all Interstates, are covered by permanent TIM Plans. The TCP process includes a TIM plan assessment to ensure adequate response throughout the construction project. TIM plans are created by many stakeholders including city/county/state law enforcement, first responders, public works, communication centers, towing and recovery, and Iowa DOT. Beyond the content of the permanent TIM Plans, Work Zone TIM Plans may include:
- Diversion Route Plan Modifications
- Additional Diversion Route Signing
- Temporary Cameras or Sensors
- Portable DMS
- Emergency Traffic Control Procedures
- Emergency Response Routes
Communications Planning and Execution
Iowa DOT separates itself from others through its commitment to proactively monitor and share information on work zone performance to mitigate unforeseen issues using several strategies:
Real- time Performance Monitoring – In partnership with the Institute of Transportation (InTrans) at Iowa State University, daily and weekly reports are shared with the statewide TMC, construction engineers, and law enforcement partners. InTrans also used machine learning to develop an application that identifies slow and stopped conditions and sends text alerts with camera images during sustained traffic delays. This allows those responsible for day- to- day operations to have an immediate awareness of traffic delays.
Flex- Enforcement – While extra enforcement is considered early in project development, sometimes not enough supplemental enforcement resources are planned. Through Iowa DOT Motor Vehicle Enforcement, additional officers can be shifted into problematic areas as needed.
- Smart Arrow Boards – The Iowa DOT has developed a specification to require smart arrow boards by 2021 for Interstate and 2022 for all state highway projects. The smart arrow boards include a GPS unit and cellular modem which continuously reports location and status. This generates an accurate record of lane closures and allows the TMC, and others via data feed, to be notified automatically with work z one closure times and locations.
- Iowa Work Zone Data Hub – Iowa DOT is partnering with InTrans to develop a “research grade” work z one data hub leveraging proposed standards and architecture proposed through the FHWA National Work Zone Data Initiative.
- Work Zone Council – A cross cutting Work Zone Council has been created within Iowa DOT to rapidly address developing issues and share new initiatives.
- Annual Work Zone Safety Awards – To highlight exemplary work and commitment, Iowa DOT has established several work z one safety awards for a range of project types using a variety of selection criteria that demonstrate compliance, innovation, and stakeholder communications.
- Improved Data Driven Work Zone Process Review Procedures – Iowa DOT is improving the procedures to complete comprehensive data driven Work Zone Process Reviews and has been selected by the FHWA as one of three states for a case study highlighting the value of this process.
Outcome, Learnings and Public Benefit
Results of Iowa’s comprehensive work zone management program have been tremendous. The following highlights how the program has helped advance Iowa DOT’s TSMO capability maturity.
- Business Processes - The TCP process is a model case study for how DOTs should approach integrating TSMO into routine business.
- Systems & Technology - The focused work z one attention has accelerated adoption of emerging technologies and leverages the partnership with InTrans for specialized expertise (e.g., machine learning).
- Performance Measurement - The routine daily and weekly reports are a great example of empowering data- driven improvements to safety and mobility throughout the lifecycle of a construction project.
- Culture - Integrating the TCP process into the Design Manual is a major milestone with positive impact on organizational culture. Developing and integrating the processes has involved nearly every Highway Administration Bureau.
- Organization & Workforce - The Work Zone Council allows for better communications across the department to improve how projects are planned and delivered.
- Relationships - inside and outside the organization have improved because the TCP process forces designers to engage stakeholders much earlier in project planning.
The core team members of the work zone management program cross several bureaus within Iowa DOT including:
- Traffic Operations Bureau
- Traffic and Safety Bureau
- Design Bureau
- Construction and Materials Bureau
- Motor Vehicle Enforcement Bureau
- Iowa State University Institute of Transportation (InTrans)