Work Zone Mobility and Safety Program

Appendix C. Issues for Consideration

Below is a list of key points and tips that have been presented throughout this work zone ITS implementation guide.

Step 1 – Assessment of Needs

  • Key point: Work zone ITS is one of several tools available to address specific safety and mobility issues in work zones. If goals and objectives become more manageable to achieve through a different technique, that technique should be selected instead of ITS. Other strategies may be more economical and effective in meeting goals and objectives.
  • Tip: Have realistic expectations. Although some ITS applications may be promoted as a catch-all solution to safety and capacity problems, field testing has not always shown conclusive benefits. Work zone ITS should be well designed and smartly applied to scenarios in which benefits are most likely to be achieved.
  • Tip: Be sure that the work zone ITS fully captures the range of impacts for which it is intended. This is particularly important for deployments that are intended to convey delay or queue length information to users. In some deployments, work zone impacts periodically extended beyond the limits of the ITS devices. When this happened, the system was unable to provide accurate information. More importantly, the motorists sat through several minutes of delay before encountering a message that there were delays and reduced speeds in the work zone. This severely limited the credibility, usefulness, and benefits of the system.
  • Tip: Stakeholder agencies, besides the deploying agency, need to be involved early. Coordination with other agencies is a primary issue that should be considered both in developing and implementing an ITS work zone. This will be important for determining how the system can work within each agency’s existing procedures.

Step 2 – Concept Development and Feasibility

  • Key point: Not all ITS deployments are complicated and expensive. For example, an additional temporary traffic sensor or two may be all that is needed to expand or enhance an existing permanent ITS deployment to be an effective tool for managing traffic impacts at a particular work zone. This was the approach taken during the I-15 CORE project in central Utah.
  • Tip: Systems need to have reliable communications. The communications network for an ITS application is vital to the operation of the system and must be reliable. Issues that may impact communications need to be addressed early in the system development and deployment process. What may seem like a trivial issue at the outset may evolve into a more difficult problem when deploying or operating the system. Such issues include whether adequate cellular capacity is available and whether there are obstructions to signal transmission due to geography or terrain.
  • Key point: Whether to use ITS to address a work zone need has to be assessed because work zone ITS may not be the only or best way to address a particular issue. For example, project staff at case study sites in Effingham and Mount Vernon, IL considered whether to use IT’S the need for queue warning. Because on the need for automatic queue warning and delay information dissemination, staff at both projects considered alternatives and decided early on that some type of work zone ITS would be deployed. There had been previous efforts by IDOT to warn drivers approaching a work zone with queues through the use of either enforcement personnel positioned upstream of the work, or through the use of IDOT staff with truck-mounted CMS. The difficulties of predicting when queues would occur, having sufficient staff available to schedule during those times, and keeping the warning device (enforcement vehicle or the truck-mounted CMS) in the proper location relative to the end of the queue reduced the practicality of these approaches. IDOT staff were also concerned with the potential liability associated with sometimes, but not always, being able to have an enforcement vehicle or truck-mounted CMS present when queues were expected.

Step 3 – Detailed System Planning and Design

  • Tip: It is important to use a proactive approach in building public awareness of the project and the information that the ITS application will provide. Successful techniques include holding press conferences, issuing news releases, and keeping local media (especially those the public turns to for traffic information) up to date.
  • Tip: Helpful hints for planning an evaluation.
    • Evaluations can be either qualitative or quantitative; however, the best evaluations employ a combination of both types of information.
    • The most effective evaluations occur when the goals and objectives for a work zone ITS are explicitly stated, measurable, and agreed to by all stakeholders.
    • Examining the role of research in the evaluation step of the project will help clarify the types of analyses that can be performed to produce benefits data.
    • It is helpful to provide a mechanism for the public to offer feedback on the project. Several agencies have used comment sections on the project websites to collect this feedback.
    • The formality and magnitude of an evaluation should match the level of the ITS deployment. An informal evaluation may be sufficient for simple systems, while a more formal evaluation would be better suited for a larger-scale deployment.

Step 4 – Procurement

  • Key Point: Procurement of ITS need not conform to a traditional approach. The Minnesota DOT issued a stand-alone, design-bid-build, best-value contract to facilitate work zone ITS for a set of three simultaneous construction projects with separate contractors on a single stretch of highway. This mechanism helped assure contractor qualifications and expertise for designing, deploying, and operating a single, quality ITS, along with performance-based considerations for the projects. The Minnesota DOT has also discussed issuing a general contract to have an ITS contractor on call. The ITS contractor would engage stakeholders and provide input and recommendations for work zone ITS early on for selected projects the agency believes will require it, stay abreast of rapidly changing technologies, and help the agency use ITS to its maximum potential.
  • Tip: Strategies for successful procurement.
    • Agencies need to consider the necessary personnel experience for operating and maintaining work zone ITS before deciding whether to purchase or lease work zone ITS, so that the procured system can be effectively operated and maintained.
    • Regardless of whether ITS is procured directly by an agency or indirectly through a construction contract, it is important that there be expertise available locally (either on agency, contractor, or vendor staff) who are tasked with day-to-day responsibility for operations and maintenance of the system to enable quick response and resolution of issues.
    • Typically, it is preferable to indirectly procure work zone ITS as part of an initial construction contract bid than as an addition through a change order to minimize costs and reduce frustration. In addition, change orders over a given amount or percent on a project may require high-level administrative approval before procurement, which can delay when the system can be obtained and deployed.
    • While change orders are not the preferred procurement approach, agencies should also recognize the potential need for change orders to modify or enhance the system once it is implemented and operational experience is gained regarding actual work zone impacts.
    • Hybrid approaches that mix two or more of the procurement approaches discussed herein are possible. For example, an agency may choose to purchase a COTS system itself through a low-bid selection process, and then hire a vendor to deploy, calibrate, and operate the system on an as-directed basis through a low-bid or other type of selection process. As another example, an agency could specify that the contractor obtain a COTS system for the purpose of providing queue warning protection upstream of temporary lane closures, considering the payment for the system as a type of mobilization cost. Then, each time the system needs to be deployed, a per-use or per-day fee could be negotiated with the contractor to cover labor costs for deployment, operation, and retrieval.
    • In some cases, agencies will specify that project funding will be withheld if ITS components are not maintained in a satisfactory operating condition as one way of increasing its importance with the contractor.
    • It is important to remember that 3rd party traffic data collected primarily by vehicle probes can provide good work zone travel time and delay information, but will be less sensitive to the onset of queues that form until the queues reach a substantial length. Only those vendors that can provide spot speed data will be effective for supporting queue detection and warning systems.

Step 5 – System Deployment

  • Tip: Allow start-up time when deploying a system. Problems will arise—such as the operation of sensors, communications (wireless or wired), calibration, or software—and will take time to address. These “bugs” require time to locate and address. Failure to allow for sufficient start-up time can lead to less than optimal performance of the system during the initial days of the project. Unfortunately, this is often the time at which the system is most needed, as drivers are encountering unexpected conditions due to the capacity and operational constraints imposed by the MOT plan, are surprised, and need and would benefit significantly from having improved information and guidance in how to best accommodate the work zone.
  • Tip: Quickly deploying work zone ITS is possible but can require extra resources. Although it is desirable to begin the process for considering, planning, designing, and deploying a work zone ITS early in the overall project development process, circumstances sometimes dictate that an accelerated timeline be followed. It is important to recognize when such circumstances arise and to dedicate enough resources to be successful in meeting that timeline. For example, a work zone ITS deployment used on the Big I (I-40) project in Albuquerque, New Mexico, was able to go from concept to full operation in only 15 weeks. However, to accomplish this, the agency had to employ several experienced ITS contractors for the ITS design, system selection, and system installation.

Step 6 – Operation, Maintenance, and Evaluation

  • Key Point: Sometimes conditions in the field may differ from what was expected during system planning and design, and adjustments may be needed. For example, queues may be longer or shorter than what was estimated before construction actually started. Personnel should monitor conditions in the field such that if queues regularly extend beyond the system signs (or detectors), the agency/contractor can consider adjusting the placement of the system components to make the most effective use of the system or adding additional devices to extend coverage.
  • Tip: Manage expectations. It is important to assess and update expectations due to true experiences of the deployment in the work zone. The deployment may have greater or lesser impacts than originally anticipated, and it is important for stakeholders to understand why that is the case.
  • Tip: It is important to ensure that information delivered to the public is as accurate as possible. If inaccurate information is provided, the public can quickly lose confidence, resulting in negative public relations.
  • Tip: Carefully consider how to set up automated information delivery and sharing with other agencies. Particularly with an automated information delivery system, it is possible to deliver too much information for the agency and its partner agencies to process effectively. The frequency, usefulness, and volume of information delivered to managers and partners needs to be appropriate or it will likely be discarded or ignored. Many ITS applications can be set to automatically deliver texts or e-mails to the agency or partners such as the media and public safety agencies. If the thresholds for delivery of these messages are not carefully considered, a recipient may be inundated with information and unable to sort out what is useful.
  • Tip: Questions to consider as you monitor the system during deployment.
    • Is the system working correctly? Are messages accurate based on conditions?
    • Is the vendor meeting the contract? Are issues being addressed promptly?
    • What are the data saying about work zone operations and safety and mobility in the work zone?
    • Does the system need to be adjusted (e.g., adjust thresholds, change the wording or timing of PCMS messages, reposition sensors, add sensors)?

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