The US federal government has mandated the use of several standard typefaces (or "Alphabet"s in their terminology) which must be used on road signs. Collectively, they are the Standard Alphabets for Traffic Control Devices, or SAFTCD, and are colloquially known as "Highway Gothic". Unfortunately, there are only really two implementations of the full set of type faces: there is a "roadgeek" set which is free for noncommercial use and there is a set which costs around $800.
This project seeks to provide an implementation of all currently-documented SAFTCD typefaces placed in the Creative Commons. They are free for all uses, and may be freely modified, so long as my original copyright message stays in the font info.
At this time, there are implementations of just two fonts: Series B-2000, and Series E-2000. E-2000 is the primary font, and B-2000 is a condensed version for use when space is tight. Most diamond-shaped signs are based on a 36" square and have 4" letters.
Note that NO GUARANTEES ARE MADE WHATSOEVER. That especially means I don't guarantee that the fonts conform to any specification.