Over the past few years, there have been many projects designed to determine an agencys sign retroreflectivity compliance across their road network. Each project has been unique in terms of how the agency collected the data and how they ultimately managed the data into the future. Recent MUTCD (Manual of Uniform Traffic Control Devices) regulations require the development of an inventory management program that documents the installation, maintenance and construction characteristics of sign infrastructure. Many agencies are faced with the daunting task of funding a replacement program that will comply with these new regulations into the future. Ultimately, the replacement plan needs to address non-compliance issues that are identified during the inventory/inspection process.
Step 1 Sign Inventory
The first step in the compliance process begins with an accurate inventory. Signs can be collected utilizing many different techniques and each technique can have its pluses and minuses. Field collection programs can involve inspectors walking the roads, mobile imaging vehicles taking pictures of the roads as well as other collection techniques designed to identify compliance issues along the road. No matter which solution is selected, it needs to satisfy the overall goals and objectives of the project while providing an accurate inventory of the agencys sign infrastructure.
Next, an agency needs to be able to match their available funding to the technology solution that achieves their project goals and objectives. It also needs to understand the trade-offs that are the necessary evil in projects like this available funding typically dictates the quality of the solution that can be provided by the service provider. Furthermore, the quality of the data collected and its usefulness can be impacted by the choice of the solution and available funding.
Remember that the ultimate goal of retroreflectivity compliance is centered on the replacement of signs once they fall below the minimum reflectivity standard as defined by FHWA. Many agencies would rather start replacing signs today instead of spending money to create their inventory and a management plan. This makes sense economically in the short-term, but can introduce problems from a long-term management perspective.
Step 2 Estimating the Replacement Cost of the Sign Network
The next graphic illustrates the total replacement cost as calculated using the FHWA Sign Retroreflectivity Guidebook for an agency with a 4,383 centerline mile road network.
The cost to replace all signs for this agency approaches $17.5 million dollars. Please note that this does not include the cost of the labor, equipment and other material costs incurred for the actual installation of these signs. The inventory of signs for this agency cost approximately $800k or roughly 5% of the total replacement cost for these signs. Although significant, this investment is crucial to ensure the longevity of the Sign Management program designed to manage these assets throughout their life-cycle.
Step 3 Choosing a FHWA-Approved Sign Management Methodology
The chart to the right illustrates the advantages and disadvantages related to a few of the FHWA-recommended methodologies. Most of these methods have been implemented in one way or another at various agencies across the Country.
The Measured Retroreflectivity method is popular at many DOTs and Toll Authorities. I believe this is the case because these agencies typically manage facilities that carry higher volumes of traffic that operate at higher speeds, thus increasing the risk and potential consequences of an accident. Many County and City agencies are utilizing the Visual Nighttime Inspection, Expected Life, Control Sign, or Blanket Replacement methods to manage their sign infrastructure. Each mentioned method is used for different reasons (financial vs. headcount) and has a lot to do with legacy management techniques (Weve always done it this way).
There really isnt a management method that can be considered The Best or The Most Cost-Effective. It is solely dependent upon an agencys goals and objectives for the management of their sign infrastructure. I typically recommend conducting an inventory first and then implementing a management plan that uses the concepts of Condition, Risk, and Valuation to help prioritize which signs should be replaced along with the best timing for the replacement. This can prove very valuable since the highest risk signs can be replaced first and the least risky signs can be programmed for replacement as funding becomes available.