Life Cycle Curves for Sign Management

One of the goals in the South Dakota Department of Transportation (SDDOT) Strategic Plan is to improve highway signs by: (1) adopting procedures for annual sign inspections and replacement plans, and  (2) eliminating unnecessary signs and upgrading remaining signs to comply with the Manual on Uniform Traffic Control Devices on 20% of the highway network annually. To facilitate achieving these goals, it would be helpful to know approximately how many years the sign sheeting on our signs retain sufficient reflectivity, legibility and color before they require replacement. This can vary based on the direction the sign is facing and the overall weather conditions the sign is exposed to. An efficient, simplified and centralized sign inventory database, including a decision-making tool in the database which could flag signs approaching the end of their performance life for prioritized inspection and replacement, would greatly improve the likelihood of accomplishing the ambitious objectives above. We currently do not have a consistent approach to planning and budgeting for sign replacement. Knowing the approximate life cycle for a given sign type as well as the effects of sign location and orientation in either shortening or extending the expected life would provide a powerful tool in maintaining our sign inventory while at the same time improving the efficiency and cost-effectiveness of sign replacement procedures. The purpose of this research project is to develop and implement such a decision-making tool. The objectives of this research project are to: (1) determine the status and expected longevity of the current sign inventory in South Dakota based on color, retroreflectivity, orientation, age and geographical distribution; and (2) develop a systematic approach to decision-making with regard to inspection and planning for replacement of signing. Research tasks of this research project are as follows: (1) Perform a literature search on the durability and performance of sign sheeting materials. (2 ) Meet with the technical panel to discuss the project and scope of work, and also review a draft survey as outlined in Task 3. (3) Conduct a survey of surrounding states and Canadian provinces to determine current sign evaluation and inventory practices and sign replacement decision-making strategies. (4) Interview appropriate state personnel to evaluate the sign inventory database as well as data collection and sign evaluation procedures and discuss sign replacement strategies being employed. (5) Assemble a database of potential sign locations for field testing which will provide reliable data for developing life cycle curves for signs incorporating color, age, retroreflectivity, orientation and geographical distribution as factors in performance. (6) Submit a work plan for conducting field testing of signs, including the equipment to be used, scheduling requirements, both in spring and fall with measurements taken before and after cleaning, over a two year period which will provide a statistically valid basis for developing life cycle curves. (7) Collect data on the approved signs modifying site locations as needed over the course of the field-monitoring period. (8) Develop a series of life cycle curves, suitable for integration into the sign inventory database, which can be used for budgeting and inspection purposes. (9 ) Provide guidelines for sign data collection, inspection and testing and formulate recommendations for testing requirements, equipment, procedures and replacement scheduling. (10) Prepare a final report and executive summary of the literature review, research methodology, findings, conclusions, guidelines and recommendations. (11) Make an executive presentation to the research panel and the SDDOT Research Review Board at the conclusion of the project.