Like a lot of bloggers, I track my site’s stats—hit counts, traffic patterns—and I noticed that a disproportionate number of the search queries people use to find my blog are about pictograms, those little symbol-signs used as visual shorthand for the tasks and objects we are likely to encounter during travel. (For some reason, this post about trash pictograms seems to be especially popular.)

So here’s a brief introduction to pictograms: The most iconic set of pictograms are the DOT pictograms. These were commissioned in the 1970s by the US Department of Transportation in an attempt to alleviate confusion between different pictogram sets in different venues. Before the DOT commission, different venues developed their own sets of pictograms, so “telephone” or “elevator” would be represented by a different symbol depending on where you were—the pictograms at LaGuardia were different from those at O’Hare were different from those at LAX, etc.  

At the DOT’s behest, the American Institute of Graphic Arts, now simply AIGA, reviewed 28 pictogram systems in use throughout the world—at airports, at stadia, at hospitals, at Olympic Games—evaluating each system for legibility and readability. (AIGA was concerned not only with how successfully a sign could convey its message, but also at what distance and at what size it could be read. That’s important for wayfinding, which is another post entirely.) Using this information, AIGA produced a total of 50 pictograms for the DOT, 34 in 1974 and another 16 in 1979.

The pictograms were released into the public domain in order to speed their adoption, and they remain copyright-free. The complete set of symbols is available online, through AIGA, in both .gif and .eps format.

There’s not a lot of secondary-source work on the pictogram, and the best resource for the history and development of the DOT pictograms is the report that the American Institute of Graphic Arts produced back in the 1970s. Symbol Signs, second edition, was published in 1993 by AIGA. (The full citation is: The Professional Association for Design for the U.S. Department of Transportation. Symbol signs, 2nd ed. New York: American Institute of Graphic Arts, 1993. The library of the nearest university is probably your best bet.)

The report is fascinating: There are tables upon tables of the different pictograms used by each of the pictogram families: 24 different pictograms for “telephone”, 40 or more for “restroom.” The report lays out, with remarkable clarity, the classifications and criteria used to determine the best format for a given pictogram. Reading the report is like going back in time, to when pictograms were part of a local culture, the local dialect of a commonly-understood speech.

As with most global standardizing movements, we’ve lost something in quest for efficiency, in our impulse to streamline, in our desire to standardize the way we communicate with the built environment. The clarity we’ve gained is (of course) more important than retaining confusing and outmoded sign systems, which is why the AIGA report is so valuable: through the report, the pictogram families survive as historical artifacts, as testament to the way we used to see.