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Initial Impetus for Project
The ClearviewHwy Type System was developed as the result of a
research program aimed at increasing the legibility and recognition
of road sign legends. The primary goal was to reduce the effects
of halation (or overglow) for older drivers and drivers with reduced
contrast sensitivity, when letters are displayed using high brightness
retroreflective materials. To satisfy these objectives, it was
necessary to identify ways to create a typeface that was more effective
than E-modified for destination legends on freeway guide signs.
A second component of the project was to compare the ease of recognition
provided by mixed case displays (initial capital letter only) vs.
all uppercase letters (Series D).The initial research assumption
was that four problems with current signage could all be solved
with a typeface that was more effective for traffic control devices
and guide signs. These problems include the need to upgrade signing
to accommodate older drivers; questions about how motorists read
sign legends with greatest speed, accuracy, and distance; and adding
more information on the roadscape at locations that are currently
heavily signed. Specifically:
| 1. |
A major FHWA study published in 1994 recommended 20 percent increases in letter height using FHWA Standard Alphabets for Traffic Control Devices to accommodate viewing distance and reaction time requirements of older drivers. This is the 65 and older age group that by 2005 will number 36 million people or about one-fifth of the U.S. driving population. That 20 percent increase in letter height would result in a 40 to 50 percent increase in the overall area of a sign because the width of the panel would be extended as well. The design team theorized that if an appropriate typeface design were developed that could effectively increase legibility distance and recognition distance by 20 percent without an increase in capital letter height, all traffic control devices could be upgraded without the physical requirements for larger signs and sign structures.
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If use of an optimized mixed case typeface proved more recognizable than all capital letters on guide signs and street name signs, there would be less need to make signs larger to accommodate older drivers while improving the basic performance of the sign.
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If these typefaces eliminated visual massing of convergent points in strokes or bleeding with adjacent letters, the problems of halation or overglow could be reduced or eliminated for older drivers viewing signs with legends fabricated with high brightness materials on backgrounds with high contrast between legend and background.
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Cities and states are attempting
to place more information on the roadscape for tourism-related
activities as well as adding regulations, and signing for pedestrian
safety in areas that are already densely packed with assemblies
of guide and regulatory panels. If guide signs are improved,
and the installations made more modular in design, the appearance
of sign clutter may be reduced while increasing overall effectiveness
of the collective installation.
Solving each of these problems was contingent on improving
the legibility, recognition, and ease of understanding of
road sign typography and providing a more consistent integration
of sign components.
This typographic development program has taken nearly ten years
and has included five separate, multi-part research studies
by PTI and TTI. The final version of the typefaces, as shown
in this website, evolved from these studies. Field reviews
of the final versions indicate that ClearviewHwy should result
in a greater than 20 percent gain in legibility and recognition
distance in each weight at the same capital letter height as
Standard Highway Alphabets, while minimizing halation. |
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