9.0 Work Zone Impacts Assessment in Maintenance and Operations

9.1 Overview of Maintenance and Operations (M&O)

Maintenance and operations (M&O) encompass the activities that help maintain and upkeep highways to be safe, usable, and at an acceptable level of operation. M&O includes both planned and emergency work that addresses preservation and upkeep of right-of-way (ROW), pavement, structures, safety devices, signs, roadside aesthetics (e.g., trees, planting), illumination equipment, and other roadway and roadside features/facilities. M&O does not include reconstruction or other major improvements. Typical examples of M&O work include installation and maintenance of traffic signs and other roadside devices, debris removal, mowing operations, utility work, painting/striping, minor guard-rail work, pavement patching, small pavement repair and overlay work, limited bridge repairs (decks and substructure), culvert replacement, traffic signal maintenance, and lighting work. Special or emergency maintenance or repair may be necessitated by storms (or other weather conditions), slides, settlements, accidents, equipment failure/outage, or other unexpected damage to a roadway, structure, or facility.

M&O may either be performed by state and local agency[1] maintenance personnel or be contracted to private entities. Contract maintenance is a predominant practice in some agencies and is increasing in many others. A majority of M&O activities are implemented through short-term and/or mobile work zones. In urban areas, M&O is generally performed at night. Sometimes, M&O activities (e.g., minor pavement overlay or pothole patching) at different locations along a corridor are combined into a single project involving a longer duration work zone that lasts anywhere from a few days to a few weeks.

9.2 Objectives of Assessing Work Zone Impacts in M&O

M&O activities are typically smaller in scale than construction projects because of the short-term nature of the work and the level of effort needed. However they do cause work zone impacts – sometimes even large impacts, depending on the type and location of the activity (e.g., day-time shoulder work on a high-volume urban corridor can lead to major slow-downs and backups). Currently, most agencies provide for work zone traffic control during M&O by using typical temporary traffic control (TTC) approaches/standards that apply to different types of M&O activities. Field crews select appropriate TTC plans for their respective activities by using standardized procedures, field handbooks, and their experience. Agencies develop (and periodically update) their typical TTC plans/standards, procedures, and field handbooks using engineering judgment, analyses, and guidance provided in the MUTCD and other sources such as the American Association of State Highway and Transportation Officials (AASHTO) Roadside Design Guide[2].

In the past, agencies mainly focused on providing for traffic and worker safety in developing their typicals and standards for M&O traffic control. Increasingly, many agencies are considering the mobility aspects of M&O work zones as well (e.g., combining and consolidating multiple activities, performing M&O during night and off-peak hours, performing M&O as part of large construction projects.). Many agencies are also recognizing the need to plan and coordinate M&O activities to minimize conflicts with other ongoing construction activities, and to minimize the overall work zone impacts on the transportation system.

The work zone impacts of M&O activities need to be addressed from the overall system management perspective in addition to the individual activity/corridor perspective. For example, a maintenance lane-closure on a particular roadway may use a TTC plan that helps maintain and manage traffic through that maintenance work zone. However if that highway is the designated alternate route for a larger construction project, closing a lane on the alternate route can reduce its traffic carrying capacity, leading to backups and delays for traffic diverting from the mainline of the large construction project. Such a situation may be avoided by scheduling the maintenance work such that its impacts are minimized (e.g., before/after the mainline construction project).

Assessing and managing the work zone impacts of M&O activities involves the following four key activities:

• Enhance agency procedures so that the direct safety and mobility impacts of M&O activities are minimized and better managed (e.g., improving TTC procedures, improving the visibility of maintenance workers/vehicles, better public information and advance warning systems, permitted lane-closure times, off-peak/nighttime work).
• Plan and coordinate M&O such that overall system-wide impacts are minimized (e.g., performing M&O activities as part of planned construction projects to minimize doing the M&O work as a separate activity – "don't dig up the same road twice").
• Implement and manage M&O activities such that they have minimal impacts on other construction projects and vice-versa (e.g., consider detour routes, diversions, adjacent highway sections).
• Incorporate features in construction projects that would facilitate future M&O with minimum disruption (e.g., wider shoulders, maintenance turn-abouts, designated pullouts).

Work zone impacts assessment in M&O involves the same concepts and guidance presented in prior sections. The types of work zone safety and mobility issues and management strategies to consider are basically the same. Therefore, this section will focus mainly on the four aspects listed above. However specific work zone impacts issues that pertain especially to M&O are discussed at appropriate locations. The reader may refer to Table 2.7 – Work Zone Impacts Considerations in Chapter 2.0 for a detailed list of the different work zone impacts issues and considerations that may be addressed.

9.3 Who Performs the Assessment?

The following is an overview of the staff that may be involved in assessing and managing the work zone impacts of M&O activities:

• Maintenance managers, engineers, and supervisors belonging to the maintenance departments of transportation agencies are the primary staff responsible for planning, coordinating, implementing and managing M&O activities. They are responsible for developing/updating standard processes, procedures, and guidelines related to M&O (e.g., developing typical TTC plans for different types of short-term work zones). They are also responsible for assessing and managing the work zone impacts of M&O activities on a day-to-day basis.
• In the field, agency and/or contractor[3] maintenance crews, and agency maintenance supervisors are responsible for implementing and monitoring their M&O activities such that their work zone impacts are minimized.
• Input from and interaction with different entities may be required at appropriate junctures (e.g., when coordinating M&O projects with the construction program for a region/district), including:
  • Agency technical staff and specialists including planners, highway engineers/designers, safety engineers, traffic engineers/managers, operations/intelligent transportation systems (ITS) engineers, pavement managers/experts, bridge managers, utility coordination personnel (water, sewage, power, gas, telecom infrastructure), and marketing/public relations staff.
  • Other stakeholders such as law enforcement agency personnel, emergency response personnel, other transportation agencies, and regional transportation management center (TMC) operators may also provide input.
  • Sometimes the input of other stakeholder groups, such as local community representatives, business representatives, other public safety agencies, trucking associations, and American Automobile Association (AAA), may also be needed.

9.4 Assessment Framework

Assessing and managing the work zone impacts of M&O activities may be performed by: (a) improving agency procedures so that the direct safety and mobility impacts of M&O activities are minimized and better managed; (b) planning and coordinating M&O such that overall system-wide impacts are minimized; (c) implementing and managing M&O activities such that they have minimal impacts on other construction projects and vice-versa; and (d) incorporating features in construction projects that would facilitate future M&O with minimum disruption. These are briefly discussed in the following sub-sections.

9.4.1 Improving Agency Procedures so that the Direct Safety and Mobility Impacts of M&O Activities Are Minimized and Better Managed

M&O activities present some of the biggest work zone safety and mobility challenges. Most M&O activities are implemented through short-term and/or mobile work zones. Unlike stationary/long-term work zones, often there are no barricades, drums, or cones to outline the work area in M&O work zones. Worker and motorist safety is the number one priority; however, it may not be efficient to setup an elaborate work zone for an activity that may take a very short time to perform, both from a resource utilization perspective as well as a traffic mobility perspective.

Therefore M&O work zones present a significant challenge in terms of:

• Delineating and protecting the work zone adequately enough to provide visibility and safety for the workers and any advance warning crew.
• Providing sufficient space and time for the crew to efficiently and effectively perform their work.
• Providing sufficient advance warning to motorists so that they may take appropriate action to slow down or change lanes well in advance of the work area.
• Setting up the work zone, implementing the work, and clearing the work zone setup such that the mobility impacts are minimal.

Transportation agencies use many processes, procedures, and guidelines that help address the above challenges. The MUTCD provides general TTC guidelines for intermediate-term stationary, short-term, and mobile operations. Many agencies use typical TTC templates and other guidelines to help setup appropriate traffic control and management plans for different types of M&O activities. A majority of such guidelines are based on the MUTCD and are customized according to the individual needs of different agencies.

The following are some additional issues that agencies can consider in assessing and managing the impacts of their M&O activities:

• Periodic review and update of agency M&O procedures and guidelines. As time passes, M&O work zone safety and mobility needs may change and agencies should update their procedures to reflect current needs. For example, in the last few years many agencies are increasingly performing all M&O activities requiring lane-closures exclusively at night due to the steady increase in traffic volumes in urban areas. In updating their procedures and typical TTC plans, agencies should identify the potential safety hazards and mobility impacts of different types of M&O activities, and recommend countermeasures that help mitigate those impacts. Advanced technologies and methods should be considered as applicable, and when available.

  The Washington State Department of Transportation (WSDOT) recommends the identification of "red zones" where short duration work zones are not a desirable choice due to poor traffic conditions (high volume, high speed, weaving areas, bridges, interchanges, etc.).

  Source: WSDOT Work Zone Traffic Control Guidelines, January 2006. URL: http://www.wsdot.wa.gov/fasc/EngineeringPublications/Manuals/Workzone.pdf (Accessed 01/26/06).

  The New York State Department of Transportation (NYSDOT) has identified seven intrusion countermeasures for stationary, mobile, and short duration work zones. They are: (1) reduced channelization spacing; (2) enhanced flagger stations; (3) rumble strips; (4) reduced speed limits; (5) police enforcement; (6) dynamic message signs (DMS); and (7) drone radar.

  Source: Identification of Traffic Control Devices for Mobile and Short Duration Work Operations, Working Paper: Evaluation Criteria and Analysis, May 24, 2004, New Jersey Department of Transportation (NJDOT), City College of New York, NC State University Centennial Campus. URL: http://www.utrc2.org/research/assets/97/wz-criteriawp1.pdf (Accessed 01/25/06).

  The Advanced Highway Maintenance and Construction Technology (AHMCT) Research Center conducts technology research for improving highway maintenance and construction. One of the research products of the center is an automated machine for cone placement and retrieval. Traffic cones are one of the most common items used to delineate work zones. However, present methods of deploying traffic cones require considerable manual effort and expose workers to the hazards of traffic. The AHMCT Cone Machine automatically lays down cones at regular intervals, and then picks them up again later. A single operator can safely and quickly open and close busy lanes during construction or maintenance.

  Source: AHMCT Research Center at UC-Davis, a joint program of University of California (UC), Davis and the California Department of Transportation Caltrans. URL: http://www.ahmct.ucdavis.edu/index.htm?pg=Cones (Accessed 01/25/06).

• Reinforce and reemphasize the safety and mobility needs of M&O activities. There may be a tendency in the field to underestimate the potential impacts of M&O activities due to the short-term nature and the size of the work. It is therefore important to reinforce and reemphasize the need to follow the MUTCD and other agency procedures and guidelines that govern the setup and management of M&O work zones. One way to accomplish this is to provide periodic training and training updates to M&O staff and field crews.

  The Wisconsin Department of Transportation's (WisDOT) work zone guidelines contains a Maintenance Supervisor's Checklist, which is as follows:

  1. Follow Part 6 and the Wisconsin Supplement of the MUTCD.
  2. Have a traffic control plan before going to the work site.
  3. Ask yourself, "What is the driver's view of the work site—at night, during peak hours, etc.?"
  4. Investigate crashes/incidents to identify if changes are needed in the traffic control plan.

  Source: Wisconsin Department of Transportation (WisDOT) Work Zone Safety Guidelines for Construction, Maintenance, and Utility Operations, January 2003. URL: http://www.dot.wisconsin.gov/library/publications/format/books/wzsguide.pdf (Accessed 01/25/06).

  The National Highway Institute (NHI) course, "Work Zone Traffic Control for Maintenance Operations (Short-Term)" provides guidance and training for field personnel working in the planning, selection, application, and operation of short-term work zones. More information is available at http://www.nhi.fhwa.dot.gov/training/brows_catalog.aspx. Enter 380060 in the Course Number box and click "Search." (Accessed 01/26/06).

• Explicitly address the mobility issues associated with M&O activities. Sometimes there may be a tendency to underestimate the mobility impacts of M&O activities that are short-term and/or mobile. However, given the steady increase in traffic volumes over the years and the need to maintain and better operate our limited highway infrastructure, it is essential to address and mitigate the mobility impacts of performing any work on our highways. This is especially applicable to urban areas with pre-existing heavy congestion. Several agencies have adopted and many more are increasingly adopting practices that minimize the mobility impacts of M&O activities. Some of the strategies to consider include:
  • Night work.
  • Off-peak work.
  • M&O activity coordination and aggregation.
  • M&O schedule optimization.
  • Enhanced public information (e.g., advance notice using the different media outlets including web sites/email, improved methods to warn motorists in advance of M&O work zones using dynamic message signs (DMS) and other active warning devices).
  • Queuing and delay analysis for setting thresholds and providing guidance on allowable work hours and permitted lane closure times.
  • Addressing the impacts of M&O activities (and vice-versa) on nearby transportation infrastructure and on other construction projects (discussed in Section 9.4.3).

  The Washington State Department of Transportation (WSDOT) uses look-up charts to determine whether or not a maintenance lane-closure can be implemented on a particular corridor (based on the road classification) at a particular time of day. This controls the traffic impacts of the maintenance activity.

  Source: FHWA Workshop Conducted at WSDOT headquarters in connection with the updates to the work zone regulations in the Code of Federal Regulations (CFR).

• Improved communication and coordination. On a day-to-day basis, M&O staff and crew members perform a variety of activities that span across different levels of complexity (e.g., something as simple as changing a bulb in a roadway light fixture to something as complicated as performing repair work on a bridge shoulder). Field maintenance crew may be involved in multiple activities and job-sites during the course of their work shift, and sometimes they may be pulled from their scheduled maintenance to tend to an emergency maintenance request. In the midst of all this, communication and coordination may falter. However, the lack of proper communication may lead to problems from both a maintenance efficiency and effectiveness perspective, as well as from a motorist impact perspective. For example, a local traffic signal crew may be performing emergency traffic signal repairs at an intersection just downstream of an Interstate highway off-ramp. The activity may lead to traffic backup onto the freeway off-ramp with possible spillover onto the mainline. If the appropriate State DOT authority or the local TMC were notified about the work, they can advise motorists about potential backups via DMSs and possibly re-route them to a different off-ramp.
  
  It is important for maintenance supervisors, staff and crew to understand that M&O activities not only have impacts at the immediate work location and corridor level, but also have system-level impacts that extend into other corridors, intersections, interchanges, etc. Sustained communications with appropriate regional/local entities (e.g., TMC operators, local/county traffic signal system operators, transit and railroad agencies, State DOT operations managers) can keep concerned stakeholders informed about any work activity that is taking place on the transportation system. Many regions have regional TMCs that provide information to motorists via DMSs, media outlets, and other information channels. If maintenance staff keep them updated on a daily basis of their planned activities (and emergency activities as and when they come up), the TMC operators can then provide periodic and timely updates to the traveling public and other agencies.

  The Wisconsin Department of Transportation (WisDOT) recommends that, if there is a rail crossing near the work area, coordination with the railroad company should occur before work starts. Lane restrictions, flagging, or other operations shall not create conditions where vehicles can be stopped on the railroad tracks with no means of escape. If traffic backups are anticipated to extend through the crossing, special procedures for warning motorists should be used, which are provided in WisDOT work zone guidelines.

  Source: Wisconsin Department of Transportation (WisDOT) Work Zone Safety Guidelines for Construction, Maintenance, and Utility Operations, January 2003. URL: http://www.dot.wisconsin.gov/library/publications/format/books/wzsguide.pdf (Accessed 01/25/06).

• Improved public information, awareness, and communication. Public inattention, lack of awareness, and lack of sufficient advance warning are often cited as a major cause of crashes and safety issues when performing M&O work. Agencies should try to use all available information dissemination channels to inform the public of upcoming/planned M&O work, and provide sufficient warning in advance of M&O work zones. Traveler information web sites/email updates (either agency or non-agency) are a good resource for keeping track of and providing information on planned and ongoing M&O activities. Several new technologies are increasingly used to warn motorists and urge them to reduce speeds in advance of M&O work zones such as DMSs (portable or pre-existing), and speed display trailers.

  The Texas Transportation Institute (TTI) conducted a survey of all State transportation agencies to obtain data on safety operations for mobile and short duration maintenance. The survey results indicated that the most significant hazards for all responding agencies were high speed traffic and inattentive motorists, which resulted in rear end crashes of safety vehicles and errant vehicles entering the shadow vehicle convoy or the work area. Some State agencies approach the solution to these issues by incorporating advance warning devices in addition to the standard MUTCD safety devices. Examples include brighter or fluorescent signs on shadow vehicles; trail vehicles with speed display boards below the arrow panel; use of better or additional lighting on shadow vehicles such as solid light bars, blue lights, or light emitting diode (LED) lights; dynamic message signs (DMSs) in advance of the work area; and police to enforce traffic laws.

  Source: Ullman, Brook R., Melissa D. Finley, and Nada D. Trout, Identification of Hazards Associated with Mobile and Short Duration Work Zones. Report Number: 4174-1. Texas Transportation Institute, College Station, Texas, September 2003. URL: http://tti.tamu.edu/documents/0-4174-1.pdf (Accessed 01/25/06).

9.4.2 Planning and Coordinating M&O to Minimize Overall System-Wide Impacts

M&O activities have both localized and system-wide impacts. Often, the lack of adequate planning and coordination between multiple M&O and construction activities performed by multiple agencies is a cause for increased traffic delays and frustration for motorists. M&O work adjacent to a construction work zone (at nearby intersections/interchanges, adjacent corridors, etc.), if performed in an uncoordinated manner, can create unwanted delays and frustration to motorists and may also interfere with the effective performance of the work. Lack of coordination between agency maintenance and construction departments during planning can result in conflicts and combined impacts that can delay project schedules and exacerbate motorist frustration.

The following are some issues to consider in planning and coordinating M&O activities so that their overall system-wide impacts are minimized and better managed:

• Account for M&O needs and potential impacts during systems planning (i.e., when developing transportation plans and programs) by coordinating construction project schedules and plans with those of M&O activities. The participation of maintenance engineers and staff in the planning and programming processes can help provide input towards such planning and coordination. For example, in developing a two-year Transportation Improvement Program (TIP) for a region, M&O activities can be planned and scheduled such that their conflicts and potential combined impacts can be minimized. Even something as simple as performing mowing operations on a highway section may not be able to take place if that highway section will be under construction. So agencies should make an effort to plan and coordinate within multiple M&O activities as well as with other construction projects.
• Coordinate and combine multiple M&O activities into a single larger project.

  The California Department of Transportation (Caltrans) uses a Corridor Management Approach for Maintenance and Construction Operations to coordinate multiple construction/maintenance projects within a corridor. For maintenance projects, a complete corridor will be closed off during the night with a "maintenance gang" performing the work. Construction projects are much longer in duration and entail coordination among different projects to be tied into one corridor project. This practice has led to a reduction in overall congestion and delay as well as improved perception by the public through coordination and planning efforts by Caltrans.

  Source: FHWA Work Zone Best Practices Guidebook, April 2000, http://ops.fhwa.dot.gov/wz/practices/best/Default.htm (Accessed 01/26/06).

• Perform M&O activities as part of planned construction projects (whenever possible) to minimize doing the M&O work as a separate activity. Another way of saying this is, "don't dig up the same road twice." For example, many agencies combine ITS infrastructure projects (e.g., laying a fiber-optic/communications conduit) along with ongoing construction projects.

  In the City of Phoenix, design and construction of city water and sewer lines within the street right-of-way (ROW) is done by the Street Transportation Department. Prior to the implementation of this policy, each entity designed and constructed their facilities in a separate project. This resulted in neighborhoods being torn up on three separate occasions to construct the project. By bringing all work under the Street Transportation Department, the work could all be accomplished in one contract thereby saving time and money, increasing safety, and having less impact and disruption to the community. The City also implemented a penalty provision for utilities that trench through new pavements.

  Source: FHWA Work Zone Best Practices Guidebook, April 2000, http://ops.fhwa.dot.gov/wz/practices/best/Default.htm (Accessed 01/26/06).

• Coordinate, implement, and manage M&O and construction activities at the regional/district/corridor level to minimize overall impacts.

  The Chicago Department of Transportation (CDOT) has a policy to sequence, coordinate, and schedule projects to minimize motorist delay and interference to affected business/residential communities. Internal coordination meetings are routinely held to discuss various projects from the Bureaus of Traffic, Highways, and Bridges that have the greatest impact on traffic. Specifically, CDOT internally discusses the upcoming construction season's major projects and proceeds to map out coordinated project letting schedules in order to minimize motorist delay and interference to affected business/residential communities. Information that comes from these regular CDOT internal meetings is used to update their public web site. This leads to construction cost savings and travel time improvements and motorists/pedestrian safety improvements within construction and maintenance work zones.

  Source: FHWA Work Zone Best Practices Guidebook, April 2000, http://ops.fhwa.dot.gov/wz/practices/best/Default.htm (Accessed 01/26/06).

• Improve ongoing and day-to-day communications on M&O and construction activities at both the intra-agency and inter-agency levels. This is the same as the "Improved Communication and Coordination" discussion in Section 9.4.1.

  The Virginia Department of Transportation (VDOT) employs a Lane Closure Coordinator for Interstate Highways in a State Highway District. The coordinator serves as a single contact for compilation and distribution of planned lane closures in the coming week. This practice helps avoid concurrent lane closures, whether they are on maintenance, construction, operation, or utility work areas, on nearby sections of roadway and helps to avoid conflicts in operations. Ultimately, traffic delay and congestion due to multiple operations in nearby areas are reduced.

  Source: FHWA Work Zone Best Practices Guidebook, April 2000, http://ops.fhwa.dot.gov/wz/practices/best/Default.htm (Accessed 01/26/06).

9.4.3 Implementing and Managing M&O Activities with Minimal Impacts on Other Construction Projects and Vice-Versa

M&O activities in the impactable vicinity of other construction projects can adversely affect traffic safety and mobility (and construction efficiency) of the construction project and vice-versa. Interfering M&O work is often cited as a major cause of construction project schedule delays and exacerbated work zone impacts. Conversely, a nearby construction project can also have a negative impact on an ongoing M&O activity.

Therefore, during the planning, design, and construction phases of a construction project, it is important to assess the potential impacts of any nearby M&O work that is scheduled to take place concurrently. During the construction process, if adverse impacts are experienced due to any nearby M&O work, appropriate actions should be taken to manage those impacts. Also before scheduling and implementing an M&O job, coordination should be performed to identify any nearby construction projects that could interfere with the M&O job or be interfered with by the M&O job. Such coordination should be forthcoming from both the construction side and the M&O side, and should take place at the planning/design level and the day-to-day operational level. Coordination and communication at the operational level can also help keep all parties informed, even in the case of emergency maintenance situations. The planning and coordination may be done as discussed in Sections 9.4.1 and 9.4.2.

Some of the issues that may be considered in assessing the impacts of M&O work on construction projects include:

• M&O that affects detours or diversion routes.
• Impacts of M&O within or adjacent to an active construction project – e.g., an M&O lane closure that interferes with a project lane closure.
• Overlapping or contradictory signs between construction project and M&O activities.
• M&O work that can result in stoppage of construction or schedule delays (e.g., utility delays).
• Multiple work zones within close vicinity of each other (e.g., along the same corridor) resulting in added motorist frustration.

9.4.4 Incorporating Features in Construction Projects to Facilitate Future M&O with Minimum Disruption

In designing construction projects (roadway rehabilitation/reconstruction, etc.) features should be incorporated, whenever possible, to facilitate future M&O with minimum disruption. Examples of such features include:

• Wider shoulders.
• Wider bridge decks.
• Maintenance turn-abouts.
• Designated pullouts.
• Use of non-contact roadway sensors (instead of embedded pavement loops).
• Making roadway and roadside structures (e.g., sign support structures, DMS message boards) easily accessible without requiring lane closures or excessive traffic interference.
• Using roadside and roadway devices that facilitate fast and easy maintenance (e.g., in the case of tower mounted equipment, using lowering devices instead of having to use a bucket truck to get on top of the tower).
• Reducing the need for and cost of maintenance/upgrade work by using longer-life materials (e.g., long-life pavement markings and lane markers).

The FHWA Highways for LIFE program focuses on how to build a highway safer, longer lasting, at a lower cost, and faster. More information on this program is available at https://www.fhwa.dot.gov/hfl (Accessed 01/18/06).

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