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Publication Number: FHWA-HRT-07-042
Date: April 2007

Maintaining Traffic Sign Retroreflectivity: Impacts on State and Local Agencies

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3. Sign Management Costs

In addition to the direct costs of a sign, an agency will also incur costs for the processes they have developed to procure, deploy, maintain, monitor, and upgrade traffic signs. The information below reflects some of this diversity and indicates the difficulty in establishing specific agency-level cost impact estimates.

3.1. Sign Management Processes

Each State or local highway agency has a sign management process that is used to add, remove, modify, and maintain the full spectrum of signs that are placed on the streets and highways within their jurisdiction. These processes vary by 1) the size of the agency, 2) the nature of the highway system under an agency's jurisdiction, 3) agreements with other internal departments, external agencies, private sector manufacturers, suppliers, contractors, and consultants, 4) the history of sign practices in the area, and 5) other factors. These processes vary from information-driven systems that allow field staff to generate work orders on laptop computers or personal data assistant (PDA) devices to arrangements that designate a member of the local council to install, fix, or replace signs with materials carried in his/her pick-up truck.

Clearly, the nature of the process, the age and adequacy of the existing sign inventory, and the resources of an agency imply that the cost impacts of implementing new MUTCD provisions will be greater for those agencies that do not have a formal sign management system already in place. Additionally, an agency that has freeway or expressway segments is likely to have responsibility for overhead guide signs, with a higher system cost than an agency responsible for a roadway network comprised primarily of residential streets.

There are various methods that an agency may use to maintain minimum levels of traffic sign retroreflectivity in its jurisdiction. These methods can be loosely categorized as assessment-based or managed replacement. Under assessment-based replacements, scheduled evaluations provide a direct measurement of the adequacy of the retroreflectivity of in-place traffic signs. Signs not in compliance with minimum levels, or likely to fall out of compliance before the next assessment, are scheduled for replacement. Managed replacement relies on information about each sign to determine when a given sign should be replaced. Varying levels of detail may be incorporated into a managed replacement system, ranging from manufacturers' warranty periods to complex lifetime models incorporating environmental conditions, traffic volumes, etc.

3.2. Sign Management Methods

The methods associated with assessment-based and managed-replacement processes are not always distinct and may be used in combination. These include:

  • Visual nighttime inspections: trained personnel assess traffic signs from a moving vehicle of a specific type.
  • Measured sign retroreflectivity: retroreflectometer readings are taken for each sign and compared to the table of minimum levels to determine whether the sign is adequate. This may be done with direct or indirect measurement devices that are appropriately calibrated.
  • Expected sign life: signs are scheduled for replacement when experience, control signs, material warranties, or other attributes dictate replacement.
  • Blanket replacement: all signs of a certain type or in a specific area are changed at specified intervals, eliminating the need to track the life of individual signs. Replacement cycles are based upon the shortest expected lifetime for the signs within the replacement group.
  • Control signs: a set of control signs is monitored to determine when signs of a specific type or group approach the minimum levels to trigger sign replacements.

These methods vary in their initial implementation costs and annual operating costs. The nature of sign management processes in an agency and the current status of the sign system will dictate the degree of need for initial assessments and replacements.

3.3. Sign Management Cost Elements

The cost elements for sign management vary by the specifics of the process. Major cost elements include:

  • Inventory assessment costs
    • Field equipment - including vehicles, retroreflectometers, safety apparel, data forms or data-logging equipment, etc.
    • Crew deployment
    • Logistics management
    • Inventory updates
  • Data processing
    • Data entry and verification
    • Linking data to a location referencing system
    • Material inventory control labeling and support systems
    • Data back-up, archiving, and recovery costs
  • Software systems
    • Sign inventory/management software
    • Software upgrades and maintenance
    • Staff training
    • Server and work stations
    • Field devices
  • Work order processing and tracking
  • Warranty monitoring
  • Salvage and recycling

These costs are a function of the size of the agency, the ability to link with other systems, the availability of support staff, and a host of other factors.

The use of sign inventory and management software is not strictly necessary for an agency to bring a sign system into compliance. However, inventories and management tools (e.g., software to schedule sign replacements for the next funding cycle) may be beneficial in making a sign management system more cost-effective. For example, an inventory of signs along a given corridor allows a simple check-off of performance during a visual nighttime inspection and permits identification of any missing signs.

Note that it is assumed that State and local highway agencies already design and install signs in compliance with the MUTCD, which includes provisions for day and night inspections and maintenance of traffic signs.

There are a number of factors that can influence the sign management costs of an agency. These include:

  • The nature of the existing sign management process and the amount of process enhancement required or desired;
  • Methods selected for enhancing a sign management process (e.g., developing a sign inventory);
  • Labor rates and work rules (e.g., nighttime inspections may add an overtime increment to the hourly wage rate);
  • Methods used to procure sign materials;
  • Decisions to fabricate signs or buy pre-fabricated signs;
  • Degree of privatization of the traffic sign system;
  • Strategic alliances between agencies to procure materials and services;
  • Using larger signs to offset the need for higher retroreflectivity levels;
  • Reducing the number of signs;
  • Applying the minimum requirements to fewer categories of signs;
  • Development of new sign materials and technologies;
  • Competition induced drops in sign material prices; and
  • Using the proposed minimums as a tool to understand driver's needs and allow some signs to remain in place longer than done previously.

Many of the above items were also identified in Section 2.4 as factors influencing the cost of individual signs. It is recognized that these factors will vary by agency, and that some of the factors will reduce the overall cost of a sign management program and other factors will increase the cost. The impacts to an agency by the factors listed above will be directly tied to the decisions of each agency to address or not address each factor. By electing to utilize cost-saving factors, the combined negative impacts of these factors may not be significant, especially when considering the assumption that all agencies are currently following the recommendations in the MUTCD.

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