Work Zone Mobility and Safety Program

STEP 2 – CONCEPT DEVELOPMENT AND FEASIBILITY

A photograph is provided showing traffic on a multilane highway and informational signage mounted on a lane divider. STEP 2 - CONCEPT DEVELOPMENT AND FEASIBILITY

This section describes key activities or considerations that should be addressed in Step 2 of the implementation process, in which a system concept for the ITS deployment is developed. The sub-steps that will be explored in Step 2 are depicted in Figure 8.

Figure 8. Sub-steps to be explored in Step 2. A text graphic shows a sequence of eight items associated with Step 2. From left to right these are 2.1 What is the overall work zone ITS concept of operations?; 2.2 What ITS solutions are available?; 2.3 What are potential benefits of an ITS deployment?; 2.4 How much will an ITS deployment cost?; 2.5 What are potential institutional and jurisdictional challenges?; 2.6. Addressing legal and policy issues; 2.7 How can project feasibility be established?; and 2.8 How can buy-in be obtained from internal and external stakeholders and other agencies? Source: Battelle
Figure 8. Sub-steps to be explored in Step 2.

2.1 What is the overall work zone ITS concept of operations?

The development of a work zone ITS concept of operations should take place in the early stages of the planning process. It should answer the question, how does the agency envision that the system will operate within the work zone? A concept of operations includes user needs and objectives that were developed in Step 1, as well as justification for and description of the proposed system, operational policies and constraints that will govern how the system is deployed, and scenarios describing how the system will function. Developing a concept of operations helps ensure the agency has thought through what it needs out of the system, which generally leads to a more successful work zone ITS deployment. Figure 9 shows the general outline of a formal concept of operations document based on the Institute of Electrical and Electronics Engineers (IEEE) 1362-1998 standard document. For a small work zone ITS deployment, the developed concept of operations document may be significantly scaled back, as seen in a concept of operations developed for a Minnesota DOT work zone ITS deployment.10

Even though a concept of operations starts to formalize the type of system that is envisioned, it is important to note that this document is solution-agnostic, describing how the system will operate but not prescribing the technology components to be installed. For example, a concept of operations should not dictate whether radar or video detection should be used, even if in some situations there may be only one viable alternative that exists.

1. SCOPE
1.1 Identification
1.2 Document Overview
1.3 System Overview
2. REFERENCED DOCUMENTS
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3. CURRENT SYSTEM OR SITUATION
3.1 Background, Objectives, and Scope
3.2 Operational Policies and Constraints
3.3 Description of the Current System or Situation
3.4 Modes of Operation for the Current System or Situation
3.5 User Classes and Other Involved Personnel
3.6 Support Environment
4. JUSTIFICATION FOR AND NATURE OF CHANGES
4.1 Justification for Changes
4.2 Description of Desired Changes
4.3 Priorities among changes
4.4 Changes Considered but not Included
4.5 Assumptions and Constraints
5. CONCEPTS FOR THE PROPOSED SYSTEM
5.1 Background, Objectives, and Scope
5.2 Operational Policies and Constraints
5.3 Descriptions of the Proposed System
5.4 Modes of Operation
5.5 User Classes and other Involved Personnel
5.6 Support Environment
6. OPERATIONAL SCENARIOS
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7. SUMMARY OF IMPACTS
7.1 Operational Impacts
7.2 Organizational Impacts
7.3 Impacts During Development
8. ANALYSIS OF THE PROPOSED SYSTEMS
8.1 Summary of Improvements
8.2 Disadvantages and Limitations
8.3 Alternatives and Trade-offs Considered
9. NOTES
9.1 Acronyms and Abbreviations
9.2 Terms and Definitions
Figure 9. General outline showing the sections of a formal concept
of operations document based on the IEEE 1362-1998 standard.

The concept of operations should clearly describe all activities associated with operation of the system, from the data flows between system components to information flows between the agency and the public. Creation of data flow diagrams, information flow diagrams, and communication charts can be valuable in helping agency staff define how the system will ultimately operate, as well as in guiding decisions affecting the overall strategy for the system. An example graphic that could be used to help staff visualize the layout of the ITS deployment is shown in Figure 10. Potential strategies can vary from simple automated systems that provide traveler information upstream of the work zone to systems that serve as virtual TMCs.

Agency staff should clearly describe the operational system strategy at the outset of the project, with particular attention to how this strategy will fit within their overall construction project. In addition, the concept of operations for the ITS deployment should make sense in the context of the existing roadway network. For example, if CMS will be used to provide messages about delay or stopped traffic ahead, it would make sense to place the signs prior to exits to alternative routes. The concept of operations can be a working document during planning stages, and can be updated as needs change and system functionality is considered. The concept of operations can also include multiple subsystems, e.g., a queue warning system, incident detection system, and VSL system.

Figure 10. High-level sketch for the concept of operations of a work zone ITS deployment in Utah. Source: Utah DOT. A base map shows major highways in the area surrounding American Fork to the north and Provo to the south in the state of Utah. The map has been modified with designated diversion routs, detector locations, signage locations, and CCTV locations. An inset diagram representing a close-up view of a segment of the multilane highway shows locations for sensors and signage. Source: Utah DOT.
Figure 10. High-level sketch for the concept of operations of a work zone ITS deployment in Utah. Source: Utah DOT.

Exclaimation Point IconKey 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.

2.2 What ITS solutions are available?

ITS technology is one tool that can be used by agencies and contractors to address a wide range of concerns or needs in a work zone. Systems can vary widely based on concerns being addressed. They also vary in scale. Not all ITS deployments are complicated and expensive.

ITS can take many forms in work zone applications. In general terms, these systems are comprised of components in the field, communications links, a TMC, and/or archived data. The National ITS Architecture provides a framework for planning, designing, and integrating ITS components.11 Additionally, permanent ITS applications may already be in place in part of the work zone area, and may be useful as components for work zone ITS. More specifically, systems include one or more of the following components, which are detailed in Table 3:

  • Sensors that collect data on current traffic conditions
  • Communications equipment to transfer the data or information developed from that data
  • Software that processes and analyzes the collected data, as well as available supplemental (e.g., weather data or traffic data from alternate routes) and archived data (e.g., historic traffic data), converting it to information for use by other components or by various end users
  • Electronic equipment to disseminate the information to the end users or to implement traffic control or management decisions that were based on that information.

Table 3. ITS components.
ITS Component Types
Sensors
  • Spot speed/volume/occupancy sensors
  • Cameras (manual visual monitoring and automated video detection)
  • Point-to-point travel time sensors (automated vehicle identification, or AVI; radio frequency identification, or RFID; automatic vehicle location, or AVL; Bluetooth; cellular telephone tracking)
  • Emissions sensors
  • RWIS/ESS
  • Vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I)
Communications Systems
  • Cellular
  • Wireless (Wi-Fi), private or public
  • Satellite communications
  • Dedicated short range communications (DSRC)
Software and Electronic Equipment
  • Portable CMS (PCMS)
  • Dynamic Signs
  • Specialized signs (e.g., variable speed limit operations)
  • Highway Advisory Radio (HAR)
  • Websites
  • Smart phone/tablet applications
  • Social Media
  • Text Alerts

These systems are available in a variety of configurations. These configurations can impact the procurement options that are available to an agency, which will be discussed in more detail in Step 4 of the document. In general, the three main categories of ITS are:

  • Stand-alone, commercial off-the-shelf (COTS) products to serve specific functions (i.e., smart work zone systems that can perform queue warning, travel time and delay information dissemination, dynamic late or early merge warnings at lane closures, etc.);
  • Customized work zone ITS solutions that are specially designed to meet a precise traffic management need, such as the deployment of temporary sensors or temporary ramp metering devices at selected problem locations to be integrated into and operated using an existing TMC. This type of system may require additional services, such as system design support and software development and integration;
  • Services or data only (no equipment) that provides the agency with information to monitor, manage, and/or measure the performance of traffic within and around the work zone. The agency makes use of what others have already deployed and does not need to procure equipment to obtain the data.

The FHWA Work Zone Mobility and Safety Program provides numerous case studies and resources available to help transportation professionals familiarize themselves with the current state of the practice on ITS in work zones.12 Topics include the benefits of using ITS in work zones, automated work zone information systems, traffic management systems including dynamic lane merge systems and speed management systems, PCMS, and work zone ITS deployment examples.

Traffic Cone IconExample: Current strategies and how they can be used.
  • The Michigan Department of Transportation deployed ITS during a total closure of I-496 in downtown Lansing. This $2 million system used 17 cameras and six queue detectors to gather and process data on current conditions, and 12 CMS to display advance traveler information to the public to help alleviate traffic congestion resulting from the full closure of a major freeway.
  • The New Mexico Department of Transportation deployed ITS during the reconstruction of the I-40 and I-25 “Big I” interchange in Albuquerque. The $1.5 million system used eight cameras, eight modular CMS; four arrow dynamic signs; four all-light emitting diode (LED) portable CMS trailers; four portable traffic management systems, which integrate cameras and CMS on one fully portable unit; and four HAR units, all linked electronically to the temporary Big I TMC to better manage incidents during the project.

Work zone ITS applications are continuously evolving to better address issues. The Transportation Research Board (TRB),13 American Association of State Highway and Transportation Officials (AASHTO),14 and American Traffic Safety Services Association (ATSSA)15 have committees and conference sessions that focus on work zone operations. These serve as forums for practitioners to share information on the latest applications and emerging technologies.

Additionally, emerging connected vehicle technologies that incorporate V2V and V2I communications will present major opportunities for communications and data gathering for work zone systems. Portable information devices such as smartphones and tablets provide increased opportunities for information dissemination by agencies, but must be used carefully because of the safety concerns associated with distracted driving.

Communications are a critical component of ITS. Table 4 summarizes the different communication systems that have been used and some key considerations for each communication option.

Table 4. Communication options, advantages, and disadvantages.
Communication System Advantages Disadvantages Comments
Cellular (commercial wireless)
  • Good in areas lacking landline systems
  • Common system interfaces available
  • Coverage may be limited, especially in rural areas away from major traffic corridors
  • Commercial system that may be “oversold” and subject to availability of signal
  • System is sensitive to terrain and time of year if deployed in areas with heavy foliage
When using wireless Internet, the agency needs to ensure that system Internet protocol (IP) address has high enough priority, so that information flows through the network as quickly as possible.
Private Wi-Fi networks
  • Inexpensive for localized communications between devices
  • Wide area coverage is possible but more costly
  • Not dependent on commercial cellular service
  • Lengthy license application may be required
  • Intermodulation studies may be required
  • Terrain may affect coverage
  • Additional infrastructure such as antenna towers may be needed for longer-range communications
  • Frequency availability may be limited
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Satellite System
  • Good for areas lacking landline systems or cellular coverage that require internet access or long-range communications
  • Not dependent on location or terrain for strength of signal (urban or rural)
  • Commercial system may be “oversold” and subject to availability of signal
  • Cost may be higher relative to other systems
  • Signal strength may fade during severe weather and heavy rain
Compare the different options to see which system provides the best fit based on project needs.
High frequency radio
  • Wide area coverage
  • Good in areas lacking landline systems
  • Not dependent on commercial cellular service
  • Inexpensive
  • Lengthy license application may be required
  • Intermodulation studies may be required
  • Terrain may affect coverage depending on frequency available
  • Additional infrastructure, such as antenna towers, may be needed
  • Frequency availability may be limited
  • Others may illegally use the same frequency causing the message to be “jumbled” or “walked on”.
Highway advisory radio systems use cellular due to issues with availability of Federal Communication Commission (FCC) license.

A factor to be considered is how various communication options are affected by physical features of the work zone, such as terrain, foliage, number and size of buildings in the area, and other wireless networks in use nearby. Wireless systems may not perform as well due to interruptions in the line of sight.

Two groups of professionals may be helpful to an ITS project manager when dealing with communications issues: state DOT maintenance personnel, and local radio contractors. Public agency maintenance personnel responsible for other communications systems used by the state can provide valuable assistance. Typically, these other communication systems are installed in the field and must meet high performance standards similar to what the ITS work zone system will require. This consideration is even more important in rural areas, where communication options become more limited due to lack of key infrastructure.

The FCC has identified unlicensed bands in the 2.4 GHz range that are suitable for supporting a variety of data and voice communications. The availability of unlicensed communications has stimulated many communications vendors to produce the necessary equipment. As such, the costs for implementing such connectivity have been reduced dramatically. The Unlicensed National Information Infrastructure (UNII) band does not require licensing, and many communications products operate on this band.

For ITS, determining the appropriate type of communication is key. Depending on the type of contracting arrangement (if any), it may be up to the contractor to select types of communications equipment that satisfy the requirements and specifications. Specifications can be written to allow for a desired equipment model or brand to be used, if the agency has a particular piece of equipment in mind (e.g., satellite communications for areas where cellular communications do not exist, such as mountainous areas).

Clipboard IconTip: 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.

2.3 What are the potential benefits of an ITS deployment?

As indicated previously, benefits of ITS in work zones are realized by the public, businesses, the contractor, and by the agency. Benefit impact areas associated with the use of ITS in work zones can include safety, mobility, improved work productivity and durability, and customer satisfaction. Table 5 provides a summary of benefits that have been experienced for various work zone ITS.

Table 5. Examples of benefits for various work zone ITS.
Work Zone ITS Issue(s) being Addressed States with Studies of Example Deployments1 Example of Benefits
Real-time Traveler Information
  • Congestion
  • Delay
  • Safety
CA, DC, NE, OR 16-19% reduced traffic volumes (diversion) on affected route (CA)
Queue Warning
  • Safety (crashes)
IL Significantly reduced speed variance; reduced vehicle conflicts; queuing crashes reduced 14% despite an increase in both lane closures and vehicle exposure.
Dynamic Lane Merge (early merge, late merge)
  • Delay
  • Aggressive driving behavior
  • Travel speed
  • Safety
  • Queue length
FL, MI, MN Reduced forced and dangerous merges by factors of 7 and 3, respectively (MI)
Incident Management
  • Incident clearance time
  • Delay
NM Reduced average time to respond and clear incident from 45 minutes to 25 minutes (NM)
Variable Speed Limits (VSL)
  • Speed management
  • Safety
VA, UT Greater speed compliance vs. static signs; reduced average speed and variation (UT)
Automated Enforcement
  • Speed management
MD, IA, IL, OR Significantly reduced speeds by 3-8 mph (IL)
Entering/Exiting Vehicle Notification
  • Safety
MN, PA Signs warn drivers of a slow-moving construction or emergency vehicle entering or exiting the roadway to reduce crash risk.
1Additional information on these case studies can be found at: http://www.ops.fhwa.dot.gov/wz/its.

2.4 How much will an ITS deployment cost?

Developing general cost estimates for various alternatives can be extremely useful in developing a plan for a realistic system. A first step is to examine the cost of similar systems deployed elsewhere in the state or in neighboring States. It is also beneficial to develop early cost estimates for the deployment options. If there are no other systems available for comparison in one’s own state or nearby, the next step is to examine similar systems deployed in other locations in the U.S. and even worldwide. These cost comparisons are made more difficult by factors that may differ between regions, such as labor rates and availability of certain types of communications.

The cost of ITS in work zones can vary widely and is influenced by the scope of the overall work zone, procurement method, the type of system, and system goals:

  • Scope of the overall work zone – The relative cost of ITS seems to be largely dependent on the scope of the overall work zone, such that the portion of the cost due to the ITS may be smaller in larger work zones and vice versa.
  • Procurement Method – The cost of the work zone ITS can be very different for a system that is leased versus one that is purchased, or even a data purchase.
  • Type of system – A more labor-intensive, complex, and specialized system is likely to be more expensive than a more standard work zone ITS deployment.
  • System goals – Although sometimes agencies will develop a general plan and then inquire about the costs associated with implementing the plan, an agency will be better able to develop an estimate if it has clearly defined its system goals and objectives and the concept of operations.

These factors can cause the cost of work zone ITS to range from several thousand dollars to several million dollars. As a rough estimate, purchasing a few sensors to add to an existing TMC might cost about $5,000 plus an additional $5,000-$10,000 for integrating them with the existing system. Purchasing a larger system that includes four sensors, a PCMS, and some operations support for communications and data software for a simple queue warning system might cost about $125,000, while doubling this to a system with eight sensors and two PCMS might increase the costs to about $200,000.

There are several ways an agency may achieve potential cost savings. As already discussed, any existing ITS infrastructure and resources can be used to help manage work zone conditions, reducing the need for some temporary resources. During a work zone project, some agencies choose to accelerate deployment and use of ITS components intended for a future permanent system. In both of these cases, the permanent ITS is not an additional cost for the work zone project, other than any additional capabilities that may be used for work zone management. Finally, the modularity of the work zone ITS can be assessed to separate “wants” from “needs” to accomplish system goals and objectives. Identifying essential ITS elements in the system up front can help to avoid excessive cuts that compromise the value of a system just to save money.

Several tools are available to help agencies develop an accurate estimate of ITS alternatives. The ITS Benefits and Unit Costs Database16 contains unit cost estimates for over 200 ITS technologies. In addition, ITS Deployment Analysis System (IDAS) is a software tool that estimates the costs and benefits of ITS investments.17 Finally, FHWA’s “Operations Benefit/Cost Analysis Desk Reference” might serve as useful guidance to agencies.18

Note that early project estimates are often insufficient to cover work zone ITS needs, and the funding amount is difficult to change by the time those who would identify a need for work zone ITS are involved in a proposed project. This re-emphasizes the need to engage stakeholders early, including staff that handle permanent ITS within the transportation agency, and to conduct work zone ITS deployment considerations with the context of TMP development so they are included in traffic management cost estimates.

2.5 What are potential institutional and jurisdictional challenges?

Institutional and jurisdictional challenges are often more difficult to overcome than the technical issues associated with technology deployment. Typical institutional or jurisdictional challenges for deploying an ITS application in a work zone include:

  • Lack of adequate funding provided in the construction contract
  • Lack of staff expertise in work zone ITS design, deployment, or operations
  • Effects of delays or traffic diversion on other routes or neighboring jurisdictions
  • Coordinating operations and incident response between agencies during incidents within the work zone
  • Issues relating to command and control of existing ITS assets, when using existing ITS infrastructure for work zones
  • Potential duplication of roles already performed by different departments
  • Changing long standing operational procedures
  • Increased or new maintenance requirements
  • Convincing management to try something new
  • Acknowledging and quantifying end user benefits for justification of work zone ITS
  • Assuring acceptable system performance.

The best means of identifying and mitigating many of these challenges is to be as inclusive as possible during the development of system objectives and the overall system strategy. Discussions with all key stakeholders can help to identify potential issues at the earliest stage of the system development process. This is especially important when planning ITS to be used in work zones near jurisdictional boundaries. Agencies in the adjacent jurisdiction should be contacted at the earliest possible point in the project planning stage. Furthermore, these initial contacts should take advantage of any existing inter-agency relationships. By engaging stakeholders early to identify possible issues, time is more likely to be available to make any necessary adjustments in staffing, policies, or resources prior to the work zone ITS deployment. These discussions can lead the way to not only avoiding problems during the duration of the work zone, but can also lead to long-term coordination between jurisdictions on a wide variety of other issues.

For many agencies, a major barrier to the deployment of ITS in work zones is the reluctance to try something new. This could stem in part from a lack of staff expertise. Information is available on different types of systems and potential benefits to help educate decision-makers and practitioners to overcome this barrier. Peers at other agencies may be useful resources. The FHWA Peer-to-Peer Program for Work Zones can provide peer connections, and conducted a work zone ITS peer exchange in May 2013 that provided valuable information exchange amongst peers.19 The deploying agency should seek multiple resources to gain a fuller understanding of any unfamiliar system. One barrier to ITS use can be that DOT staff with ITS expertise are in a different department from those doing road design and construction, and those two groups often do not interact regularly. Sharing expertise between those who know ITS and those who know work zones can increase the chances for an effective ITS procurement and deployment. In some cases, it may be desirable to hire staff that have more expertise and familiarity with work zone ITS for this and future deployments.

2.6 Addressing legal and policy issues

A number of legal issues must be considered in planning to use ITS in work zones. The most obvious question is whether the type of system being designed is permitted in the current laws and regulations. For example, if the agency desires to use automated enforcement as part of a VSL deployment, it is important to know whether automated enforcement legislation is in place in that jurisdiction. Other legal issues to be considered include the potential increased liability for placing ITS equipment in the work zone and archiving of certain data collected by ITS components. For example, some agencies have discovered legal implications related to collecting and storing video images of crashes. Additionally, the agency should consider possible liability issues about how warnings and messages are given (e.g., if the ITS fails to detect a queue and issue the appropriate warning, has liability been increased?). In considering these issues, the agency should also consider the overall benefits of having a system and any work zone risks (e.g., for crashes) it may help mitigate as well.

Traffic Cone IconExample: Automated Speed Enforcement in work zones.
Several states, including Illinois, Maryland, Washington, and Oregon, allow the use of automated speed enforcement in work zones. Each of these states has required enabling legislation before deployment of these systems. As an example, the legislation for Washington state* includes:
  • Restrictions on the locations where automated speed enforcement would be allowed;
  • Specified only images of the vehicle and vehicle license plate were allowed;
  • Requires the automated speed enforcement zone be clearly marked;
  • Specifies the method for notifying registered vehicle owner and vehicle owner responsibilities
*See Engrossed Substitute House Bill 1175 of the 62nd Legislature, 2011 Regular Session for Washington: http://apps.leg.wa.gov/documents/billdocs/2011-12/Pdf/Bills/House%20Passed%20Legislature/1175-S.PL.pdf

2.7 How can project feasibility be established?

Based on the steps outlined above, key stakeholders should assess the overall feasibility of the original approach and the need to revisit overall objectives for the system. For example, objectives for the system may simply be outside the available budget, in which case objectives might be constrained. Another key consideration in assessing project feasibility is whether ITS is the best TMP strategy to deploy to address the identified needs, or if other non-ITS options may be better for the given situation.

Assessing project feasibility is especially important when planning work zone applications that involve more risk, such as larger deployments that involve more cost or deployments that may involve sensitivities. Examples of these types of deployments may include automated speed enforcement (in this case, due to higher political risk) or route diversion from highways to local roads. Such applications are more likely to draw additional scrutiny, encounter additional challenges, and may incur higher costs that should be considered when assessing project feasibility.

In addition to the project manager, key stakeholders that should participate in this step include senior agency managers, contracts personnel, and engineering staff. Senior managers are needed because they may have originally defined the operating strategy that may have to be revised, and because they can provide accurate information on the availability of funding and other key resources. Contracts personnel can identify various contracting options available, as well as discuss advantages and disadvantages of each of these options. Engineering staff may be needed if questions arise regarding the feasibility of the project schedule or technical approach. In some cases, it may be helpful to have engineering staff perform modeling to help establish the need for a system and to assess how likely impact mitigation is to occur in the event that a system is deployed. For example, modeling of the work zone may show long queues that become manageable if 10 percent of traffic diverts, which may be achievable with real-time traveler information provided by ITS.

Numerous sets of criteria have been developed and could be used to establish project feasibility. Some criteria, such as those developed by Michigan DOT, are specific to various ITS, e.g., dynamic lane merge system, real-time information system, and PCMS with radar capabilities. Similarly, criteria have been developed for advanced traveler information systems under the Smart Work Zone Deployment Initiative.20 These criteria consider factors such as queue lengths, average daily traffic (ADT) and peak period traffic volumes, availability of alternate routes, and sight distances. North Carolina DOT developed criteria for use of an ITS-based SMARTZONE system in work zones based on whether the location is urban/suburban, rural, or mountainous.

FHWA drafted a general set of scoring criteria that agencies can tailor as desired for their use as one possible way to assess the feasibility for ITS (see Table 6). The intent for these criteria was to assist decision makers by providing a structured approach to considering the need for work zone ITS on specific projects. For each result, other mitigation treatments should be considered, as applicable, in addition to work zone ITS since ITS is only one possible solution for stakeholders to use to address a given issue in a work zone and may not be the best alternative.

Table 6. Example of possible criteria for assessing feasibility of work zone ITS. (Source: FHWA)21
Criteria Score
Factor 1 – Duration of work zone: Long-term stationary work will have a duration of:
  • >1 construction season (10 points)
  • 4-10 months (6 points)
  • <4 months; procurement and installation timeline is available prior to work starting (3 points)
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Factor 2 – Impact to traffic, businesses, other destinations, or other users (e.g., extremely long delays, high risk of speed variability, access issues) for the duration of work is expected to be:
  • Significant (10 points)
  • Moderate (6 points)
  • Minimal (3 points)
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Factor 3 – Queuing and Delay: Queue lengths are estimated to be:
  • ≥2 miles for periods ≥2 hours per day (8 to 10 points)
  • 1-2 miles for periods of 1-2 hours per day (6 to 8 points)
  • ≤1 mile, or queue length estimates are not available but pre-construction, recurring congestion exists for periods <1 hour per day (4 points)
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Factor 4 – Temporal Aspects of Traffic Impacts: Expected traffic impacts are:
  • Unreasonable for a time period that covers more than just peak hours (10 points)
  • Unreasonable during most of both morning and afternoon peak hours in either direction (6 points)
  • Unreasonable during most of a peak hour in either direction (3 points)
  • Unpredictable; highly variable traffic volumes (1 point)
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Factor 5 – Specific Issues Expected (0 to 3 points each based on judgment)
  • Traffic Speed Variability
  • Back of Queue and Other Sight Distance Issues
  • High Speeds/Chronic Speeding
  • Work Zone Congestion
  • Availability of Alternate Routes
  • Merging Conflicts and Hazards At Work Zone Tapers
  • Work Zone Hazards/Complex Traffic Control Layout
  • Frequently Changing Operating Conditions for Traffic
  • Variable Work Activities (That May Benefit From Using Variable Speed Limits)
  • Oversize Vehicles (Percent Heavy Vehicles >10%)
  • Construction Vehicle Entry/Exit Speed Differential Relative to Traffic
  • Data Collection for Work Zone Performance Measures
  • Unusual or Unpredictable Weather Patterns Such as Snow, Ice, and Fog
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Total Score empty cell
If the total score is:
  • ≥30 – ITS is likely to provide significant benefits relative to costs for procurement
  • ≥10 and <30 – ITS may provide some benefits and should be considered as a treatment to mitigate impacts
  • <10 – ITS may not provide enough benefit as a treatment to justify the associated costs
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Table 7 presents another possible way to consider when to use work zone ITS. It can be used as a general application guide to assess the characteristics and conditions existing or anticipated in a given work zone that would help justify implementation of one or more of the systems.

Table 7. Possible work zone ITS applications to consider for various critical project characteristics.
Critical Project Characteristics Work Zone ITS Applications
Queue warning Real-time traveler information Incident management Dynamic lane merge Variable speed limit Automated enforcement* Construction vehicle entrance and exit warning Temporary ramp metering Performance measurement
Frequent planned lane closures are expected, which will create queues that cause high speed differentials between queued and approaching traffic Characteristic could be addressed with this work zone ITS application Characteristic could be addressed with this work zone ITS application empty cell Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. Characteristic could be addressed with this work zone ITS application empty cell empty cell empty cell empty cell
Emergency shoulders will be closed through the work zone and frequent stalls and fender-benders are expected to occur that will cause queues because they cannot be quickly moved to the shoulder Characteristic could be addressed with this work zone ITS application Characteristic could be addressed with this work zone ITS application   empty cell empty cell empty cell empty cell empty cell empty cell
Travel times and delays through the work zone will be highly variable and real-time information can improve pre-trip and real-time route choice, departure time, and possibly mode choice decisions empty cell Characteristic could be addressed with this work zone ITS application   empty cell empty cell empty cell empty cell empty cell empty cell
Roadway access for emergency response vehicles will be significantly constrained by the project, increasing response and clearance times empty cell empty cell Characteristic could be addressed with this work zone ITS application Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. empty cell empty cell empty cell empty cell empty cell
Frequent incidents are expected to occur within the project Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. Characteristic could be addressed with this work zone ITS application Characteristic could be addressed with this work zone ITS application empty cell empty cell empty cell empty cell empty cell empty cell
Having an operator able to view an incident within the project and assist responders in bringing appropriate equipment to the site will significantly reduce incident duration empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell empty cell empty cell empty cell empty cell
A long-term lane closure will create a v/c condition that is very close to 1.0, and improved flow rates through the lane closure could reduce the likelihood that a queue would form, or reduce its duration significantly when a queue did form empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell
The potential exists for queue spillback from the work zone into upstream interchanges or intersections (and resulting increase in cross-street congestion and rear-end crashes) due to an unequal utilization of all lanes, such that the encouragement of the use of all lanes for queue storage would reduce that probability of spillback conditions. empty cell Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. Characteristic could be addressed with this work zone ITS application empty cell empty cell empty cell empty cell empty cell
Work activities will frequently occur for which lower speed limits would be beneficial to have on a temporary basis (i.e., during temporary lane closures on freeway mainlanes, for temporary full road closures, during periods construction vehicle/equipment access into and out of the work space from the travel lanes, etc.). empty cell empty cell Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. empty cell Characteristic could be addressed with this work zone ITS application empty cell Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. empty cell empty cell
Traffic speeds through the project vary widely due to oversaturated conditions during the peak period, and the timing and extent of congested travel will vary significantly day to day empty cell Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. empty cell empty cell Characteristic could be addressed with this work zone ITS applicationempty cell   empty cell empty cell empty cell
A reduced speed (and thus speed limit) is believed to be necessary because of work zone hazards that are not readily apparent to motorists and so will not likely result in lower speeds driven empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell empty cell
The project plans limit ability of enforcement to operate (no shoulders, barrier on both sides, long stretches between interchanges) empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell empty cell
Access to and from the work space occurs directly from the travel lanes empty cell empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell
A high number of construction vehicle deliveries into the work space will be required during the project empty cell empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell
The location and design of the access points could create confusion for motorists (i.e., access to the work space looks like an exit ramp and is near an existing actual exit ramp) empty cell Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell
Little or no acceleration lane is available for construction vehicles entering the travel lanes from the work space empty cell Major Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator. empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell empty cell
Capacity reductions in the work zone now create an oversaturated condition due to merging ramp vehicles empty cell empty cell empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell
Temporary ramp geometrics have constrained acceleration lane lengths empty cell empty cell empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell
Work activities have temporarily disabled one or more permanent ramp meters within the limits of an operational ramp metering system empty cell empty cell empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application empty cell
Work zone ITS is already being deployed for other purposes empty cell empty cell empty cell empty cell empty cell empty cell empty cell empty cell Characteristic could be addressed with this work zone ITS application
Project documents include traffic mobility performance requirements (i.e., maximum allowable delays) that must be monitored to ensure and quantify compliance and subsequent incentives or penalties to be issued performance specifications of mobility impacts [delay or queues] empty cell empty cell empty cell empty cell empty cell empty cell empty cell empty cell Major Input
The agency chooses the project for assessment purposes as part of its federally-mandated bi-annual process review empty cell empty cell empty cell empty cell empty cell empty cell empty cell empty cell Major Input
*Assumes that the state transportation code allows use of automated speed enforcement in work zones
Source: Battelle
Filled bullet Characteristic could be addressed with this work zone ITS application
Circle Characteristic could be addressed with this work zone ITS application if some modification(s) were made or real-time actions taken by an operator.

Table 7 attempts to illustrate how some of these applications may be designed to address certain conditions, but could also address other conditions through some modifications to the typical deployments or the introduction of a human operator who could make real-time adjustments in how the systems respond. Similarly, some work zone issues could be addressed through more than one type of system. As an example, a real-time traveler information system could address work zone conditions where unexpected or variable periods of travel delays and congestion will arise, and there is potential to encourage route, departure, and mode choice diversions through the provision of real-time information. However, these same conditions could also be addressed through implementation of a work zone incident management system. Whereas a typical work zone traveler information system will operate autonomously based on a limited set of rules, the incident management system would rely on an operator present to monitor and detect incidents to also modify the information dissemination devices if needed to encourage diversion.

An ITS application may not be appropriate for every work zone nor be the best solution for a given issue. Other alternatives should also be examined. The expected project location, project impacts, and project duration are likely to influence whether or not a particular ITS solution merits consideration. Other factors like traffic volumes and project layout will also influence whether or not work zone ITS are applicable for a particular project. For example, if the concern is potential congestion in a work zone, one solution can be to use ITS to monitor traffic conditions and provide traveler information. Some other possible mitigation strategy alternatives to using ITS are a public information campaign to reduce travel demand in the area; maintaining more lanes by using the shoulder to carry traffic; conducting work at night when traffic volumes are generally lower; including lane closure restrictions in the contract to affect less traffic and minimize impacts; a motorist assist patrol to quickly identify and address vehicle breakdowns and other incidents; or using a movable barrier to provide an additional lane for peak period traffic flow.

Exclaimation Point IconKey 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.

Stakeholders should consider the differences in costs, as well as benefits that each alternative would provide. For example, even though an ITS deployment would likely cost more than a public information campaign, the ITS deployment provides real-time information and can monitor the work zone status. While a public information campaign is good for steady state conditions or specific events, ITS is good for a dynamic work zone in which roadway configuration may change on a frequent basis. In weighing the benefits and cost of different strategies for addressing work zone issues, it is helpful to keep in mind that work zone ITS can give multiple benefits that sometimes exceed the primary objectives. For example, a work zone ITS deployment may enable traffic management in real-time, better deal with changing traffic conditions, and provide data for both performance monitoring and assessment of benefits, even though initial objectives may have been focused on providing information to travelers. More benefits may be provided by work zone ITS than cheaper alternative solutions (e.g., public information campaigns that only addresses the initial objective).

Several analytical tools have been developed for use in evaluating work zone traffic control strategies. The FHWA has developed a traffic impact analysis spreadsheet, known as QuickZone.22 QuickZone can estimate the delay impacts of various work scheduling or configuration alternatives, such as doing work at night instead of during the day or of diverting the traffic to various detour routes during different phases of the construction. The FHWA Traffic Analysis Toolbox includes guides for work zone modeling and simulation.23 These documents provide guidance on using analytical tools in work zone planning and management, including work zone analysis, selecting a modeling program, and approach.

2.8 How can buy-in be obtained from stakeholders and other agencies?

Ideally, buy-in from core stakeholders should be achieved during Step 1. However, some agencies may choose to wait until the vision for the system is more mature before bringing in the entire spectrum of stakeholders listed previously. The size and magnitude of the work zone, as well as the expected complexity and scale of deployed ITS technology in the work zone, will impact the timing. For example, if a simple off-the-shelf system is being deployed, a general notification to key stakeholders should be sufficient. However, other cases will require more active participation, closer coordination, and stakeholder buy-in earlier, such as a case where ramp metering or a transit or truck bypass is being considered for a work zone.

The scope of the work zone project will affect the level of stakeholder buy-in required, as well as how difficult it will be to attain it. Buy-in for temporary or short-term work zone projects that do not affect long-term operations will generally be easier to obtain than similar buy-in for long-term projects requiring permanent changes in procedures or staffing responsibilities, although the costs may be harder to justify for shorter-term projects. As complexity or duration of the project increases, so too does the requirement for greater contact with affected agencies.

Peer-to-peer contact, i.e., developing inter-agency relationships among staff at the same level, is typically the most effective form of interaction. These relationships should be developed at the line supervisor and even the operator level, depending on the scope of the project. Cross-training, i.e., having staff from a different agency work alongside host agency staff for a fixed period of time, has been effective in fostering better working relations and understanding of key needs. Another useful tool in obtaining buy-in from varying stakeholders is to communicate the estimated benefits for each individual agency being recruited. Answering the question “What’s in it for me?” is an effective way to elicit support from other agencies.

Key Takeaways
  • The main product of Step 2 is a concept of operations report. This report builds on information gathered and established in Step 1, and documents a vision for the system, such as the one illustrated in Figure 11. It should incorporate the goals and objectives of the system and the system strategy, and serve as a guide for system development. The report should also provide a summary of the processes in Steps 1 and 2 and document stakeholder input. The report should be scalable to the extent and complexity of the system.
  • Engage ITS staff as a source of expertise.
  • Achieving a broad level of consensus in this step is a prerequisite to moving to Step 3. Presenting the results of Step 2 to a stakeholder group is essential. Agencies sometimes skip this consensus-building step and move on to requirements and design. When that happens however, the agency will likely get mired in unanticipated questions and issues from stakeholders later that would have been easier to address sooner.

Figure 11. The product of this step should include concept of operations scenarios, such as this graphic for a work zone traffic management system. A graphic shows a multilane highway with a work zone and a set of electronic sensors and signage for traffic management. The electronic signals are processed by various monitoring subsystems to provide information such as destination distance and current travel time.  Source: Battelle
Figure 11. The product of this step should include concept of operations scenarios,
such as this graphic for a work zone traffic management system.

10Document can be found at: http://www.dot.state.mn.us/guidestar/2006_2010/icone/iconeconceptofops.pdf
11For more information about the National ITS Architecture, see Appendix A, and http://ops.fhwa.dot.gov/its_arch_imp
12Available at: http://www.ops.fhwa.dot.gov/wz/its.
13Available at: http://www.trb.org.
14Available at: http://www.transportation.org. For information specific to work zone ITS, see: http://ssom.transportation.org/Pages/ITSinWorkZones.aspx.
15Available at: http://www.atssa.com.
16Available at: http://www.benefitcost.its.dot.gov.
17More information about IDAS can be found at: http://idas.camsys.com. IDAS is available for purchase from the McTrans Center for Microcomputers in Transportation at the University of Florida at: http://mctrans.ce.ufl.edu.
18Available at: http://www.ops.fhwa.dot.gov/publications/fhwahop12028.
19For more information, including the materials from the work zone ITS peer exchange, see: http://www.ops.fhwa.dot.gov/wz/p2p/index.htm.
20See “Criteria for Portable ATIS in Work Zones” by Alan J. Horowitz at: http://ssom.transportation.org/Documents/2005_horowitz_atis_criteria.pdf
21This is not the only way or criteria that could be used. Agencies can tailor this to their needs or use their own criteria.
22More information about QuickZone is available at http://ops.fhwa.dot.gov/wz/traffic_analysis/quickzone/. QuickZone is available for purchase from the McTrans Center for Microcomputers in Transportation at the University of Florida at: http://mctrans.ce.ufl.edu.
23More information on the FHWA Traffic Analysis Tools, specifically Work Zone Modeling and Simulation Guidance in Volumes VIII, IX, and XII can be found at: http://ops.fhwa.dot.gov/trafficanalysistools.

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