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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:
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:
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:
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.
Topics: research, safety, visibility and retroreflectivity
Keywords: research, safety, retroreflectivity, maintained retroreflectivity, minimum maintained retroreflectivity, impact, impact assessment, impacts analysis, national impact assessment
TRT Terms: reflective signs, retroreflectivity