@article{ref1,
title="A durable reflective sign system for low-volume roads",
journal="Transportation research record",
year="1979",
author="Nettleton, Tom",
volume="702",
number="",
pages="295-303",
abstract="Some reflective signs on National Forest land are subjected to extreme temperatures and snow burial. Field units noted the reflective sheeting peeling from these signs after only one winter. In 1972 the Forest Service Missoula Equipment Development Center (MEDC) began testing outdoor signs of various substrates, reflective sheeting, application techniques, and clear coatings. The goal was to find the right combination of materials and manufacturing processes to produce a reflective sign that would remain maintenance-free for 7 years. The 3M Co. agreed to take part in the testing. After five winters of outdoor exposure, several combinations of substrate, reflective sheeting, application techniques, edge seal, and clear coatings were rated free of structural failure that would require maintenance. It was recommended that outdoor reflective signs for Forest Service use be manufactured as follows: (1) Engineering-grade sheeting and letters with heat-activated adhesive (HA) on aluminum substrate--cycled twice through the heat vacuum applicator and clear coated. (2) Engineering-grade sheeting (HA) and pressure-sensitive (PS) or HA letters on high-density overlay (DHO) plywood substrate--cycled twice through the heat vacuum applicator. When PS letters are used, the sheeting is cycled through the heat vacuum applicator once before applying the message and once after. (3) High-intensity sheeting (PS) with heat-activated letters on HDO plywood substrate--cycled once through the heat vacuum applicator. Signs are equally durable with silk-screened letters. The top edges of all signs are protected with Scotchcal brand transparent film.<p />",
language="en",
issn="0361-1981",
doi="",
url="http://dx.doi.org/"
}