BGS Technology

[Mergingtraffic]

I've been wondering....it seems up until the early 2000's the technology for BGS signs are far behind other types of signage.  For example:  with button copy and demountable copy: why did it hang on so long when other types of signs such as LGS, warning and regulatory signs have been using adhesive type material for their characters? 

The same goes for non-reflective background button copy....states were using that until the 1980s when LGS or other signs have had reflective backgrounds since the 1950s at least?

[hbelkins]

Kentucky and West Virginia still use demountable copy for guide signs (what Kentucky calls "panel signs.")

Perhaps the thinking is that if the legend needs to be changed, it's cheaper to pop off old letters/route markers and install new ones, and with smaller signs, it's cheaper to just make a new one.

Most recent Kentucky example I can think of is when the "TO US 127 South" legend was removed from the signs approaching KY 151 on I-64 eastbound. Trucks used this as a shortcut to Lawrenceburg, but trucks were banned from this route after a public outcry. So the references to US 127 were removed. I know one new sign was put up, but on the others, the US 127 marker and working were taken down and the KY 151 marker was centered on the sign and reinstalled.

Also on I-79 approaching Corridor H, the US 33 and 119 markers were removed and moved over to make room for a new US 48 marker on those exit signs.

[J N Winkler]

The issue here is economics rather than know-how.  From the very beginning, many agencies opted to use retroreflective sheetings for large sign panels as well as small ones, but others opted to use non-retroreflective facings because their greater durability offset a disadvantage in performance that was at the time considered slight and acceptable.

This Caltrans report on a late-1950's experiment with retroreflective guide signs on the US 40 Roseville bypass (now part of I-80) illustrates how agencies sorted through the issues involved.

http://www.dot.ca.gov/newtech/researchreports/1959-1960/59-19.pdf