| Road Manager
How Readable Are Your Street Signs?
The right size, color, font, and style
can make the difference between readable or not.
by Ruth W.
Stidger, Editor-in-Chief
New innovations, such as solar-powered smart street signs that light up
for easy reading at night, can add to readability.
Creating signs that are easy to read as drivers pass at 35 or 40 miles
an hour in their vehicles takes more than just following suggestions in
the Manual on Uniform Traffic Control Devices. In fact, the MUTCD offers
only a couple of pages of very generalized guidance.
You can do much more — and do it economically.
Content first
Before considering the actual design of street signs, consider their
content. One of the best guides to content and design is Sun Microsystem’s
Documentation Style Guide.
The guide suggests that you:
Realize that fewer letters and words makes signs easier to read. A
street sign might show the base name of the street, such as Main in
large letters, and the sub-word or abbreviation for street, road, drive,
or avenue in smaller letters.
Consistency increases readability. Follow the same design font,
style, and placement on all of your street signs so readers are familiar
with the content and know what to watch for.
Avoid confusion. Use of non-English words or dual-language street
signs presents too much information. Supplement English-language street
signs with separate icon signs or a second sign in another language if
directions or other data is needed.
Care how it looks
In an online forum, members of the American Institute of Graphic Arts
get involved in an ongoing discussion of street sign design.
“People take badly designed signs for granted,” says Keith Tam in
Vancouver. “Most graphic designers are not interested in designing
street signs...[and they] are generally designed...by engineers, or worse,
government committees...good signage is a reflection of how important [an
agency] thinks its people’s everyday lives are. It’s about time Canada
and the U.S. pay some attention to the design of signs (and I have a
typeface specifically for the purpose.”
“Some street signs are so subtly colored,” says Jean Shirup from
Jacksonville, Florida, “that we miss them all together. We still use all
caps on most signs and make them even harder to read, especially from a
distance or in bad weather.”
Readable or legible?
A font is just another name for a style of type. Some of these are much
easier to read than others, so why not pick one that stands out.
There are two basic types of fonts — serif fonts with little tails at
the beginning and end of some letters, or sans serif fonts without the
tails.
Serif fonts are easier to read, but are less legible than sans serif
fonts. By poor legibility, designers mean that it is more difficult to
distinguish between letters.
So, what should you use? For short signs with a few words, such as
street signs, legibility is more important than readability, so they
should be in a sans serif font.
All caps?
Using all capital letters increases legibility, too, which is why
street signs are usually in all caps — whether graphic designers like it
or not.
Arial is one sans serif font commonly chosen for legibility. It is used
on many Web sites and in many e-mail programs for just that reason.
Not all designers agree on using all caps on street signs. Some like an
initial cap followed by lower-case letters, which will be more readable,
but probably less legible.
Use of languages and a country’s culture can affect this legibility
versus readability, too. Both American English and German use more
capitals than British English. In fact, however, many U.S. and Canadian
street signs are designed with a combination of upper- and lower-case
letters.
Practical design
Sign manufacturers often know which signs receive the best response and
are the most legible.
Garden State Highway Products, Incorporated provides several tips for
constructing street signs:
The brighter the reflective sheeting and the larger the sign
panel, the better. Best contrast colors for both day and night are white
characters on a green or blue background.
A common rule of thumb is to use 1 inch of letter height for each
40 to 50 feet of legible distance. Optimal letter height is 6 inches or
more.
Letter fonts vary by stroke width and letter width from B
(thinnest) to E modified (thick and wider. Series C is optimal. Using
upper- and lower-case letters and increasing spacing between letters on
a sign both contribute to better esthetics and readability.
The MUTCD provides practical guidance, too. Lettering on street name
signs should be at least 6-inches high in capital letters or 6-inches high
in lower-case letters, it says. Larger letter heights should be used for
street name signs mounted overhead.
The MUTCD suggests that supplementary lettering, such as street,
avenue, or road may be smaller, but at least 3-inches high.
Street name signs should be retroreflective or illuminated to show the
same shape and similar color both day and night. The legend and background
should be of contrasting colors.
By contrasting colors, the MUTCD says it suggests a white legend on a
green background. A border, if used, should be the same color as the
legend.
In business districts and on principal arterials, street name signs
should be placed on at least diagonally opposite corners so that they will
be on the far-right side of the intersection for traffic on the major
street.
In residential areas, at least one street name sign should be mounted
at each intersection.
Signs naming both streets should be installed at each intersection.
They should be mounted with their faces parallel to the streets they name.
Street name signs may be installed at both midblock and intersection
locations. To optimize visibility, street name signs may be mounted
overhead.
On intersection approaches, a supplemental street name sign may be
installed separately or below an intersection-related warning sign.
Street name signs may also be placed above a regulatory or stop sign
with no required vertical separation.
At intersection crossroads where the same road has two different street
names for each direction of travel, both street names may be shown on the
sign along with directional arrows.
Lighting Up
Daytime and nighttime color specification and luminance (reflectivity)
standards for sign materials were published in the Federal Register at the
end of July last year. Nine tables provide the standards for various sign
colors, including fluorescent ones.
Beyond reflective materials, though, companies are beginning to make
self-illuminating street signs.
The 34th Street Partnership
in New York City designed, developed, and installed 200 self-illuminated
street signs. Their system is based on LED technology.
 The
background color for the signs (dark blue) ensures that the diodes within
the frame of the sign light up with the white font areas and that the
background remains dark.
The designers chose Frutiger 65 as an easy-to-read font.
Fastened to light poles, the signs’ light-up capability stems from
drawing power at the pole.
Another company, Ledi Lite in Jerusalem, Israel,
provides solar-powered LED smart street signs, which require only 1% of
the electric power of those fully powered by electricity.
Little electrical infrastructure is needed, saving initial as well as
operating costs. The street signs are a spinoff of the firm’s
solar-powered smart house numbers.
Reprinted from Better Roads Magazine
August 2003 |
