FHWA Series A

[Quillz]

Does anyone know what year Series A was decommissioned and what the reasons behind it were? I've read various documentation about signage in New Zealand, which still uses Series A, and it only allows it to be used on signs that are not designed to be read while in motion. I would imagine this is probably the reason Series A was retired in the USA, but is this the only reason?

[Scott5114]

I've always heard it was done away with for legibility reasons, which makes sense.

As for the date, why not poke around in some old MUTCD's and figure it out from there? https://ceprofs.civil.tamu.edu/ghawkins/MUTCD-History.htm

[J N Winkler]

No edition of the US MUTCD has ever had this information, AFAIK, but the 1998 edition of the New Zealand MOTSAM has a table giving the legibility values of various FHWA alphabet series as percentages of that of Series D (which is nominally 50 feet of reading distance per inch of letter height).  I forget the specific values but I think with Series B you are already below 60% of the legibility of Series D.

I think this information needs to be disseminated more widely in the US in order to discourage state DOTs and other agencies from trying to economize on sign panel area by using condensed alphabet series.  In the rulemaking that led to the 2003 MUTCD, when FHWA proposed giving states the option (subsequently granted) of using mixed-case legend other than Series E Modified/Lowercase on signs, I tried to have them restrict mixed-case legend to Series E Modified/Lowercase in order to establish a floor below which legibility would not pass.  This suggestion was rejected.

[Quillz]

Found my answer in a PDF document I downloaded months ago:

In 1966, the Federal Highway Administration re- printed the Standard Alphabets For Traffic Control Devices. This edition contained upper case series B, C, D, E, E Modified, Lower case E Modified and F (series A was deleted from this edition). These Al- phabets were placed on 1/4 inch grids which elim- inated the need for the previous tables of dimen- sions. However, the 1966 edition did contain six tables for character widths and spacings for upper case letters and numerals. A simplified spacing chart also was included for E Modified characters.

[agentsteel53]

interestingly, my source for Series A was a 1968 Park Service document that had the grid as well as the lengths-and-radii.  (in some cases, inconsistent - I had to build the digit "8" by inspection, for example)