There are two standard specifications for sign sheeting materials in the United States: AASHTO M268 and ASTM D4956. The AASHTO specification is based more on nighttime driver needs and the ASTM specification is based mostly on the performance of different products. While both specifications classify sign sheeting materials, neither specification provides guidance to help agencies select the appropriate sign sheeting materials. ASTM D4956 is more of a product based specification while AASHTO M268 is more of a performance based specification. The AASHTO M268 specification was developed by a team of state DOTs so that sign sheeting materials can be classified in a meaningful way. Research is needed to develop guidelines for M268 for selecting the most appropriate sign sheeting materials.
The objective of this project is to develop guidance that can be used by highway agencies in the process for selecting sign sheeting materials using AASHTO M268. This guidance should address current regulations, driver needs, the latest human factors research, cost, availability, durability, ease of use, maintenance, sign type, typical placement and other relevant factors. The research should include a critical review of previous research related to sign sheeting materials and their effectiveness, identify and evaluate the process currently used for selecting sign sheeting materials, and develop guidelines. The guidance should describe the types of sign sheeting materials, the specific design conditions where they perform best, and develop scenarios for sheeting type use for specific sign locations according to driver needs. The guidance will recommend sign sheeting types for sign design, location, and placement while taking into account the retroreflectivity of various sign sheeting types and economics.
Work on the project was delayed due to the need to change principal investigators but is now actively underway.