Indiana LTAP


To remain effective, traffic signs need to be clearly legible to all motorists. Their retroreflectivity is an important factor in their legibility. Recently, the Federal Highway Administration (FHWA) has proposed a set of minimum retroreflectivity values to which all signs shall conform. The purpose of this study was two fold; to investigate the fiscal impact of these proposed minimums on roadways managed by counties, cities, and towns within in the State of Indiana and compare the accuracy of a simple nighttime inspection method to the more labor intensive measured retroreflectivity method.

Estimates performed on the collected data suggest that the fiscal impact of these proposed standards will be felt greatest by cities with an estimated statewide total cost of $6.6 million. The statewide fiscal impact on counties and towns was estimated to be $4.9 million and $2.7 million, respectively, for a combined total impact of $14.2 million. The analysis also showed that the nighttime inspection method, with minimally trained personnel, provided an 88 percent level of accuracy and was completed in approximately half of the time that it took to directly measure retroreflectivity. It is recommended that agencies initiate a structured sign inspection and replacement program that incorporates a nighttime inspection method. The proposed six year phase in period, in conjunction with this structured sign inspection and replacement program should help to reduce the immediate fiscal impact felt by local governments within the State of Indiana.


sign retroreflectivity, retroreflectivity guidelines, fiscal impact, nighttime inspections

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