The goal of this work was to determine, quantify, and present alternative approaches for agencies to meet the Federal Highway Administration's (FHWA) proposed minimum levels of retroreflectivity for signs. This study used current North Carolina DOT sign maintenance practices to synthesize a list of approaches to enable the state to comply with the standard. The fundamental contribution of the work lies in identifying and evaluating alternative approaches to evaluate sign retroreflectivity to ensure compliance with the standard while minimizing the cost and labor required to do so. The four approaches formulated were: 1) Nighttime visual inspection (current method), 2) Improve nighttime visual inspection procedures, 3) Implement a sign inventory management system (no visual inspection), and 4) Combination of alternatives #2 and #3. It was the ultimate determination of this study that, although the most costly, alternative 4, be adopted by agencies. It was also recommended that an evaluation be made periodically to determine what benefits and improvement in sign condition, if any, have resulted from the approaches implementation.
Forecasting skilled construction labor demand ensures that the construction industry can train and supply an adequate workforce. Crucial to developing reliable forecasts is the collection of accurate and consistent data on which to base projections. This article summarizes research efforts to formally identify and collect quality economic and construction industry data intended for use in a labor forecast model. The methodology used to collect data for five key independent variables (interest rate, material price, construction output, productivity, and real wage) and a dependent variable (labor demand) from a variety of data sources is discussed. An assessment of the availability and quality of the data is made, and recommendations are given on how it can be improved. With these recommendations, more extensive data collection can be undertaken to produce accurate and consistent data. Doing so will provide the construction industry with more meaningful skilled labor data to support accurate forecasts for planning, recruitment, and retention efforts. This article fills a significant void in addressing construction industry data.
A research project to determine the appropriate sign inspection and replacement procedure was conducted at North Carolina State University and sponsored by the North Carolina DOT. The purpose was to determine the optimum strategy for sign inspection and replacement under different conditions to respond to the pending retroreflectivity requirements. This paper reports on a spreadsheet tool developed to quantitatively evaluate the effectiveness of different sign inspection and replacement scenarios. The spreadsheet was designed for yellow and red engineer-grade sign sheetings, and takes into account sign vandalism and knock-downs as well as normal sign aging. The spreadsheet provides estimates of the number of signs in place that would not meet the minimum retroreflectivity standard and the cost of the sign inspection and replacement program.
The results from a number of trials of the spreadsheet show that agencies that generally conform to the key assumptions made to build the spreadsheet should consider replacing all signs every seven years, as that insures that no aged signs are in place at a relatively low cost. If total replacement is not possible, an inspection program using retroreflectometers every three years appears very competitive in its effectiveness with a program using typical visual inspection rates each year. The retroreflectometers appear to allow fewer deficient signs, while the typical visual inspection program costs are lower for a given vandalism rate. More conservative visual sign replacement rates do not appear to offer distinct advantages, because typical replacement rates with visual inspections every two or three years allow relatively high numbers of deficient signs to remain on the roads.
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