Abstract
The Secretary of Transportation was directed by Congress, in the U.S. DOT Appropriations Act of 1992, to revise the manuel on Uniform traffic Control Devices (MUTCD) to include a standard for a minimum level of retroreflectivity that must be maintained for ....signs which apply to all roads open to public travel. The purpose for developing such values is to insure that signs maintain a level of performance related to the minimum visibility requirements of drivers. In 1993 the Federal Highway Administration (FHWA) proposed a framework containing minimum levels of retroreflectivity. The final minimum retroreflectivity values are expected to be included in the next edition of the (MUTCD). The proposed minimum retroreflectivity values are likely to be presented in the MUTCD as guidelines; however, once they have been established, the public will expect the Texas Department of Transportation (TXDOT) and other transportation agencies to follow them. The establishment of the final minimum retroreflectivity values and guidelines will have a significant impact on TXDOT. The objective of this thesis was to determine the most cost effective strategy for TXDOT to implement in replacing traffic signs that do not meet the expected minimum retroreflectivity values. This thesis includes a review of previous work on retroreflectivity and related subjects; interviews with TXDOT personnel; surveys of state traffic engineers, TXDOT district personnel and TXDOT sign crews-the collection and evaluation of sign retroreflectivity data in Texas; an economic analysis of alternative sign replacement strategies; and a sensitivity analysis of key variables within the economic analysis. The recommendations in this study will allow TXDOT to implement the most cost-effective sign replacement procedure at the time the new standards go into effect. This will ensure that material, manpower, and other expenditures are minimized, resulting in an overall benefit to TXDOT. Based on this review and analysis, it is recommended that TXDOT implement a Sign Management/Inventory System to meet the expected minimum retroreflectivity values and to effectively manage the traffic signs on Texas' highways.
McCaleb, James Bradley (1996). Evaluation of alternative sign replacement strategies. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -M324.