TRANSIT FACILITY DESIGN FOR PERSONS WITH VISUAL IMPAIRMENTS



United States Architectural & Transportation Barriers   Compliance Board

1111 Eighteenth Street, N.  W. *Suite 501 Washington, D.C.  20236-3894

(202) 653-7834 [Voice or TDD]



 The Architectural and Transportation Barriers Compliance Board (Access

Board) is charged with enforcing the Architectural Barriers Act of 1968

(42U.S.C. 4151), developing the Minimum Guidelines and Requirements for

Accessible Design (MGRAD) for the standards under that act, and

providing technical assistance for Title V of the Rehabilitation Act of

1973, as amended.  In developing the minimum guidelines, and providing

technical assistance on universal design, the Access Board sponsors

research on various issues.



The Access Board has not yet determined which, if any of the

recommendations contained in this document will be incorporated in

revisions to MGRAD as regulatory requirements.  This pamphlet, provided

to meet the Access Board's statutory mandate to provide technical

assistance, contains selected recommendations from several research

reports as advisory guidance.  Most of the complete project reports

(some have since gone out of print), which include descriptions of

methodology and findings, can be obtained either from the Access Board

or the National Technical Information Service, Springfield,Virginia.



This document is disseminated under the sponsorship of the Access Board

in the interest of information exchange.  Neither the Access Board nor

the United States Government assumes legal liability for its contents

or use thereof.



Several new and existing rapid rail transit (subway) systems have begun

to take into account the needs of persons with various disabilities in

their design and operation.  Newer stations often include elevators for

persons who have difficulty using stairs and escalators; elevators

better serve persons with mobility disabilities. Some systems provide

verbal announcements of stops.  Some have provided telecommunication

devices for deaf persons (TDDs) for customer information and

communication; and some have provided visual displays of public address

announcements.  In general such improvements benefit all members of the

general public.  However, accidents on rapid transit platforms

involving persons with visual impairments have raised concerns among

architects, engineers and transit providers as to whether current

design considerations are adequate.



Clearly, the perception of blind and visually impaired persons as

"helpless victims" of the environment is incorrect.  Many people who

are visually impaired or blind are quite capable of independent

mobility and wayfinding with the aid of canes and guide dogs.  The

environment provides a variety of cues such as sidewalk edges, curbs,

building walls, and sounds to allow people with limited vision to

navigate. In addition, most people considered "blind" have some usable

vision and can perceive light which, coupled with sound, permits them

to judge traffic patterns, determine the location of open elevator and

subway car doors, and avoid many obstacles.



In fact, the primary means of accommodating individuals with all types

of disabilities, including visual impairment, in rapid-rail transit

systems is simply to apply the common principles of good design such as

general illumination, adequate circulation space to reduce congestion,

the placement of elements such as entrances, ticket machines, fare

collection, boarding areas, etc. in a logical functional sequence, and

adequate signage and information.  the single most important factor in a

given system is consistency in station design and layout.  Consistent

design does not necessarily mean identical design but a reasonable

expectation on the part of a new transit rider that, having successfully

used one station, the same elements can be found in similar locations

in another. If public transportation is to attract significant numbers

of new riders, with or without disabilities, everything that can

possibly enhance orientation and wayfinding for those riders should be

incorporated into the design.



 For individuals with visual impairments, the second most important

factor is having good mobility skills. For all persons, wayfinding and

mobility are learned skills and independent mobility varies greatly

from person to person (everyone knows somebody who can get lost on his

or her own block and somebody who can find his or her way around the

most confusing city). Wayfinding and mobility can be enhanced by

practice and formal training, particularly where environmental and

personal circumstances change; and there are programs across the

country specifically designed to improve the skills of persons with

visual impairments. In the case of rapid transit, mobility and

wayfinding skills are system-specific. For example, the average rider,

with or without visual impairment, who learns to use the Washington,

DC, Metro-rail system will not necessarily be able to apply that

knowledge in using the New York subway system since the systems are

dramatically different.  Transit systems can help everyone by providing

clear, concise information to the general public in a format also usable

by persons with visual impairments, and by working with local mobility

training centers to develop system-specific training programs.



In the past several years, however, there have been increasing numbers

of reports of persons with visual impairments falling from subway

platforms,  Explaining these accidents has been the focus of ongoing

debate and discussion.  Some people presume these accidents are due to

poor mobility skills or the failure to apply them properly others feel

the transit station design is at fault.



Can Improved Mobility Training Solve the Problem?



One well-documented case where a person who is blind fell to the tracks

involved an individual with good mobility skills who was not only

familiar with the system but had safely used that station on a daily

basis before the accident.  Such instances seem to imply that even those

with relatively good mobility skills and familiarity with the

environment can encounter difficulty. 



Mobility training alone may not be sufficient to prevent such accidents.

The range of wayfinding abilities is as widely disparate among trainees

as it is among others in the general population.  In addition, many

individuals with visual impairments do not have access to formal

mobility training.  For example, one of the largest segments of the

visually impaired population consists of elderly people whose vision

has gradually changed over time.  These people may not realize they are

"visually impaired."  For others medication or illness may contribute

to "night blindness" which is exacerbated by moving from daylight into

a dimly lighted subway station.  finally, there are large numbers of

low-income people who, because of inadequate access to health care and

other disability-related services, receive no mobility training. Yet

the low-income segment of the population is the one most heavily

dependent on public transportation.



The Importance of Good Design



A transportation agency must plan and design the safest system possible

for people with and without good wayfinding and mobility skills, one

consistent with overall operating constraints and maximum independent

accessibility.  As valuable as mobility training may be, it is not a

"design feature" which can be put into place and maintained for the

benefit of everyone, nor can it be incorporated in building codes or

standards for accessible design.  Designers must also recognize,

however, that there is an element of risk for any person with or

without a disability to participate in society and that risk can only

be reduced, not completely eliminated, without denying that person the

right to participate. 



Recognizing the importance of good design, the Access Board has

sponsored several research projects to identify design features which

can be incorporated in buildings and facilities to improve

accessibility. Some projects relevant to subway systems have

investigated the slip resistance of surfaces, contrast requirements for

persons with low vision, the tactile readability of incised and raised

letters, detectability of surfaces by cane and foot, and lighting and

finish requirements for signs. These projects relied on data developed

through subject testing or experience of actual blind and visually

impaired users of public transit.  The reports from each of those

studies contain a series of recommendations and a bibliography.



The recommendations for rail transit stations and other fixed-guideway

transportation terminals contained in this brochure are drawn from the

above reports and other related research.  The edge-cuing provisions

are intended for use where a sizable drop-off exists.  Such drop-offs,

if not detected, could result in a fall into the path of a transit

vehicle.  In Automated Guideway Transit systems (sometimes called

"people movers") where platform screens are provided with doors that

open only when a vehicle is available for boarding. Edge-cuing is

unnecessary.  The studies did not present evidence that tactile cues

are needed at other locations such as stairs or escalators (which

usually have a metal service-plate detectable by cane and foot).

However, recommendations for lighting levels, signage,and

slip-resistance are applicable in other settings. 



When applying the recommendations below, it is important to keep in mind

that all transit facility users, including those with visual

impairments, must be able to detect and react to directional and safety

cues in sufficient time and distance to take appropriate action. This

principle applies to features such as signage and edge-cuing in

relation to the way the facility is used.



LIGHTING		 	



Good general illumination should be provided.  Incandescent

ceiling-mounted downlights should not be used as the sole source of

illumination on any accessible route or space.



Relatively uniform, diffuse general illumination is critical for people

with various disabilities as well as for the general public. Especially

on platforms and accessible routes, lighting should be uniform and free

of glare.  Ceiling mounted downlights and similar directional lighting

create alternating pools of light and shadow.  Persons with glaucoma,

cataracts and other conditions which cause light to be scattered and

persons who wear corrective eyeglasses often experience extreme

variations in reflected light as they pass beneath a succession of

downlights.  The phenomenon can be both disconcerting and dangerous. 

Substituting florescent panels for downlights creates more uniform

illumination and can save money on electricity.  Compared with

incandescent lights, half as many fluorescent fixtures provide better,

more uniform light at a fraction of the cost of installation,

operation, and maintenance.  There are many other satisfactory lighting

systems which also provide adequate illumination and economy. 



Illumination levels in the areas where signage is located should be in

the 100-300 lux range (10-30 footcandles):



Based on tests of subjects, optimal success at reading a variety of

signs and typefaces was achieved using alighting level of 300 lux (30

footcandles) at the sign panel itself.  The ambient lighting level need

not be as high when good lighting is provided at the sign.  When the

illumination level was reduced to 100 lux, the success rate decreased

by 24%.  When the illumination level was reduced to 100 lux, the

success rate decreased by 24%.  When the level was raised to 500 lux,

the success rate decreased by 9%.  In rapid rail transit systems where

quick recognition of signs and directions is critical for everyone,

slightly higher than usual lighting levels at signs may have a

significant positive effect on ridership.  Care must be taken, however,

to ensure that glare is eliminated or reduced.



EDGE CUING



The edges of platforms should be identified with a material differing in

resilience from the platform itself.



Several research projects have tested the detectability by cane and foot

of various materials. Tests showed that variations in resilience, sound

and texture were detectable. However,despite stated requirements in

some accessibility standards,  textural changes in materials have been

found to be the least detectable. In studies sponsored by the Access

Board, differences in sound characteristics of surfaces tapped by a

cane and differences in resilience could be detected most reliably. 

Since sound cues can be masked by transit vehicles, crowd noise, or

echo, they are not suitable cues for use in transit facilities or for

persons with hearing impairments. Difference in resilience between two

adjacent materials appears to offer the highest detectability and the

best solution for identifying transit platform edges.



The cue results from the contrast between a hard and resilient surface. 

The cue should be consistent throughout the system.  In some stations,

the entire surface of the platform has been covered with a resilient

material textured with raised circles while the platform edge is granite

or concrete.  Other systems have placed a resilient strip along the

platform edge in contrast to the concrete or clay tile platform surface

material.



The edge-cuing material should extend the entire length of the platform

edge and be at least 42 inches wide, starting at the platform edge.



The difference between hard surfaces and various materials, ranging from

relatively common vinyl or rubber flooring material, tennis court

surfacing, and steel grating or plates, was detected by subjects within

the distances of 30 inches to 48 inches.  In both Access Board studies,

and those conducted by other agencies, 90% of subjects stopped within

42 inches of the leading boundary between the different materials.



The edge-cuing material should be firmly attached to the platform and

maintained to prevent loose edges from becoming a hazard.   Several

common resilient surfaces can be detected by cane and foot in contrast

to an adjoining material. However, installation and maintenance are

critical to ensure that the material does not present a hazard to

pedestrian traffic.  All edges must be firmly attached to the platform

substrate to prevent edges from becoming a tripping hazard. 

Installation of a continuous of nearly continuous strip may pose fewer

problems than individual tiles.  On the other hand, individual tiles

may be easier to replace when damaged or dislodged. Careful

consideration must be given to maintenance and installation before

selecting a particular material.



The edge-cuing material should visually contrast with the primary

flooring by at least 70% as determined by the formula:   Contrast =

[(B1-B2)/b1} x 100 where B1 = light reflectance value (LRV) of brighter

area B2 = light reflectance value (LRV) of darker area



In general, the edge-cuing material should be the light areas.  The

research did not suggest that a particular color is important. Research

sponsored by the access Board did not attempt to determine whether

distinct identification of vehicle door position, as installed in some

systems, has any effect.  



The same contrast ratio is also recommended for signs (see later

section).



The edge-cuing material, and floor surfaces of  all accessible spaces

and routes, should have a  static coefficient of friction of 0.60.



Obviously, the edge-cuing material and the platform itself should be

slip-resistant.  Persons with mobility impairments are more markedly

affected than others by the surface characteristics of the flooring. 

Typically, persons without mobility impairments require coefficient of

friction values from 0.2 to 0.3. Crutch users and amputees may require

coefficients of friction ranging from 0.7 to 1.0, while wheelchair

users require coefficients of friction of 0.5 to 0.7.  Slip resistance

should be measured with one of the testers, such as the NBS-Brungraber

Tester, recommended in the "Slip Resistant Surfaces" report.



In addition to slip resistance, the platform, accessible spaces and

routes, and edge-cuing material should be stable (a surface that

remains unchanged by contaminants, temperature, or applied force, so

that when the contaminant or force is removed, the surface returns to

its original condition) and firm (a surface that resists deformation by

either indentations or particles moving on the surface) so that it does

not pose a hazard or decrease the accessibility to persons with other

disabilities.



SIGNAGE



The characters and background of signs should be eggshell (11-19 degree

gloss).  



Eggshell is a standard designation of finish which minimizes reflectance

yet permits cleaning of a sign surface. Matte finish soils easily, is

difficult to clean, and is susceptible to vandalism.  



Directional, informational and emergency signage characters should be no

smaller than 1/2 inch and visually readable at the minimum practical

viewing distance. 



People generally adjust their viewing distance to read signs. 

Therefore, signs with small characters must be able to be approached

closely.  Subjects tested were able to read signs with 2-inch capitals

from an average distance of 6 feet.  Results indicate persons with low

vision need to be ten times closer to read a sign than those with

normal vision.   Projecting the size/distance scale developed in

research suggests 1-inch caps should be viewable from a maximum distance

of 3 feet, 2-inch caps should be viewable from a maximum distance of 9

feet, etc.  Thus, the 1/2 inch cap sign must be approachable to within

1.5 feet to be legible for persons with limited vision.  Since most

overhead signs are suspended somewhere between 7 and 9  feet, and the

eye-level of a wheelchair user is about 4 feet, a wheelchair user with

a visual impairment would need to be able to approach to about 5 feet

of the vertical plane of the type of sign commonly used in terminals

(3-inch caps).  This suggests, if the sign needs to be read quickly or

while the viewer is moving this distance may be too short and the sign

characters should be larger.  



The spacing between letters should be "wide" by industry practice;

generally, the space between letters should be 1/16 the height of

capital letters.



Wide spacing was found to be easier to read for persons with low vision

and helped to reduce the halo-effect around letters in internally

lighted signs.  Space between words should be equal to the capital

height for words with all capitals and 6/10 of capital height between

capitals and lower case letters. 



Letters on signs intended to be read by touch should be raised, upper

case, sans serif or simple serif type.



Tests have shown that incised letters, permitted under some standards,

cannot be reliably read by touch.  For signs intended to be read only

visually, no statistically significant differences were found between

serif and sans serif type except for type faces with extreme flourishes

and deviations in stroke width (e.g., Columbian Italic).  For signs

that must be read and understood quickly, especially for life safety,

sans serif typefaces with optimal proportion and stroke width (e.g.,

Helvetica Medium and Helvetica Regular) are best.



Characters should be light on a dark background and contrast with their

background by at least 70%.





Under the same lighting conditions, dark characters on a light

background were significantly harder to read by test subjects.  The

contrast ratio is determined by the equation noted above for contrast

of platform edge-cuing.



Pictograms should be accompanied by the equivalent verbal description

below.



For a 6-inch sign (border dimension) a 1-inch capital height is

suggested.  large pictograms (6 inches) were more effective than

smaller ones, suggesting a minimum size for directional and

informational signage.



ADDITIONAL CONSIDERATIONS



Some of the recommendations from research sponsored by the Access Board

are for changes to the regulatory requirements which will be considered

by the Board during future rulemaking.  Other recommendations are not

easily quantifiable or may require further research to verify

conclusions. For example, public address (PA) system announcements are

a vital source of information, but can also be a cause of both

confusion and irritation for all people, especially in large, open areas

such as those in transportation terminals and airports.  Such

announcements are frequently unintelligible due to poor-quality sound

systems, poor acoustics of the facility, or lack of training of persons

making the announcements.  Moreover, these factors are affected by

noise such as arriving or departing trains. Rather than improving

intelligibility, increasing volume usually increased distortion.



Some transportation facilities have begun introducing automatic verbal

directional information, such as "talking signs" to direct people to

stand to the right on escalators or announce that a particular train is

entering the station.  Research has determined that, where such

announcements are provided, the voice should be recorded or digitized

human speech rather than synthesized speech.  For such verbal

information and for PA announcements, the placement of more speakers, at

lower power, often is more effective than increased volume. 



Noise in transit facilities is not only unavoidable, it provides

valuable cues.  The sound of an arriving train or the door-closing

annunciator are important for everybody.  However, extraneous noise

which can mask other sounds should be avoided whenever possible. For

example, the rush of air through high-power air conditioners or blowers

can significantly interfere with the sound of a cane tap and can mask

PA announcements.



Sound characteristics are also important in emergencies when various

alarms must be heard and correctly recognized.  Characteristics of

visual alarms for persons with hearing impairments are the subject of

another technical assistance document available from the  Access Board. 

Additional research also suggests that certain auditory alarm

characteristics are more readily recognized than others, especially by

persons with some hearing impairment.  Preliminary results indicate that

variable tone or intermittent alarms, rather than steady bells or

tones, are easier to detect in noisy conditions.  This subject will be

covered by future technical assistance publications.



Designers and transit operators needing further information on the

recommendations contained in this brochure and other design

considerations to improve access to all people should contact the

Access Board at the address below:



U.S. Architectural and Transportation Barriers Compliance Board



1111 18th Street, NW, Suite 501



Washington, DC  20036



(202) 653-7848 (voice or TDD)



REFERENCES



"A Multidisciplinary Assessment of the State of the Art of Signage for

Blind and Low Vision Persons", final report, Dr. Edward Steinfeld,

University of new York, Buffalo; sponsored by U.S. ATBCB, 2985



"Detectable Tactile Surface Treatments", final report, Jon Sanford,

Craig Zimmring, Georgia Institute of Technology; sponsored by U.S.

ATBCB, 1985. 



"Information systems for Low Vision Persons," Peter Muller-Munk

Associates; sponsored by U.S. ATBCB, 1986



"Slip resistant Surfaces", final report, Dr. B.T. Kulakowski,

Pennsylvania Transportation Institute, Pennsylvania State University;

sponsored by U.S. ATBCB, 1988.



"Tactile Warnings to Promote Safety in the Vicinity of Transit Platform

Edges," Dr. Alec Peck, Billie Louise Bentsen, Boston College; Sponsored

by the U. S. Department of Transportation, 1987.





.TCEL.

.

