Kenneth L. Stewart
October 25, 2002
Council of Citizens with Low Vision International
Subject: Guidelines for Public Rights-of-way Dear Board Members:
Following are comments on the Access Board’s Draft Guidelines for accessible
public rights-of-way. I regret that I have not included specific references by
Section number but the absence of an index or table of contents in the draft
makes it quite arduous to locate particular entries during preparation of this
DETECTABLE WARNING STRIPS
A requirement for tactually and visually detectable warning strips on the street
edge of every curb ramp is very important.
Full-height curbing not only provides for road drainage and safety protection
for all pedestrians, it also provides valuable locational and directional,
information for pedestrians with limited or no vision. The curb is, of course,
detectable topographically but it is also often tactually distinctive and is a
visual element creating a shadow line for many low vision travelers.
Any curbing removed to permit the street-crossing access essential for
wheelchair users, also removes a crucial street feature for vision impaired
pedestrians. There must be a new element added to replace that important
feature. The detectable strip must in all instances be at the border between
pedestrian territory and the area where motor vehicles are moving. Visual
detectability is established by light vs. dark contrast. The meeting line of the
ramp and the roadway is the best place for the visual contrast to appear, a
white detectable strip abutting an asphalt road surface, for example. The
necessary visual contrast can also be accomplished internally with a white
four-inch border against a black interior detectable strip, for example.
ACCESSIBLE PEDESTRIAN SIGNALS
The Draft Guidelines section requiring accessible pedestrian signals is quite
well formulated and identifies very effectively the characteristics of
appropriately designed and positioned APS’s.
Criticisms offered in opposition to the installation of accessible pedestrian
signals are not germane to the present generation of devices which are not loud
enough to disturb anyone, not ambiguous so as to confuse anyone, not
stigmatizing in any way (actually they reinforce compliant street behavior by
the general population) not distracting to pedestrians listening for other
traffic cues and, are quite modest in cost, especially when compared to the
total cost of signalizing an intersection for vehicles and the general
The Draft Guidelines set an appropriate tone for the design of roundabouts.
These intersection configurations have been demonstrated to move vehicular
traffic through converging streets more efficiently and more safely than
conventional intersections and therefore are a reasonable street design in some
locations. However, they do not accommodate all categories of pedestrians
without significant supplementary features. Thus a particular roundabout may be
legitimately classified as a vehicles-only site with all pedestrian use
prohibited. Typically in this circumstance a signalized intersection nearby is a
reasonable alternate route for all pedestrians. Roundabouts which accept some
pedestrians must accommodate all pedestrians with necessary features to do so
EDGE DETECTION ALONG RIGHTS-OF-WAY
It is extremely valuable to any person traveling by long white cane or by
dependence upon very limited vision, to continuously detect at least one edge of
the pedestrian access route.
At street crossings, high contrast crosswalk markings create effective visual
edges (e.g., white stripes on dark pavement), and the Draft Guidelines should
encourage research and experimentation on ways of making the stripes tactually
detectable in a form which can withstand traffic wear and snowplows. The ideal
stripe would have an outer edge distinguishable from an inner edge straight edge
versus serrated, for example. In that way, the tactual or visual detection of
lust one of the stripes would orient the traveler as to which side of that
stripe to move.
The provision of a continuous edge, or shoreline, along a sidewalk is more
difficult to assure. It too though is an important access feature. The Board’s
Guidelines work in that direction by limiting street furniture to just one side
zone of the pedestrian access route. Adding a visually and tactually detectable
element along the clear side of the sidewalk would be particularly helpful where
the route passes alongside an open area with a surface similar to the sidewalk.
That circumstance is confronted by a vision impaired pedestrian walking by a
large paved parking lot that blends smoothly into the sidewalk with no raised
border elements such as a fence, bollards, or wheel blocks. A low vision
traveler also confronts this problem when passing a service station with wide
vehicle-approach aprons abutting the sidewalk.
SIDEWALK FURNITURE VISIBILITY
The Guidelines appropriately regulate overhangs on sidewalk appurtenances so
that a long cane will detect obstructions. The Guidelines also should prescribe
high visual contrast so that these elements are detectable visually as well. The
concrete bench placed on a concrete sidewalk is a safety hazard to a low vision
pedestrian. A simple solution like making the vertical members in the bench
black, establishes the needed visual detectability simply and economically.
Likewise a curbside bollard which is black is very helpful. The current common
practice of using galvanized metal elements or painting vertical sign stanchions
and parking meters grey, is the least helpful. Mid-tones are much less
detectable than either visual extreme, light or dark.
The type and quantity of artificial lighting provided along the pedestrian
access route are very important to low vision travelers. While needs vary from
person to person, several generalizations can be made-- High glare sources are
difficult; lights which shine dire into the eye are undesirable; intermittent
fixtures creating alternating bright and shadowy areas are not helpful.
Underpasses or other route segments which depend on artificial illumination at
all times, should when possible have light intensity levels which adjust by time
of day. The adjustment should mimic the exterior ambient lighting, that is, in
bright daylight the passage should have bright lighting, and subdued lighting at
night when the pedestrian’s eyes will be adapting from a dim ambient conditions
and returning to a dimly lit exterior area after departing the underpass.
CONSTRUCTION SITE DETECTABILITY
Temporary construction sites must be required to mark the route so as to be
detectable by cane and by limited vision. High contrast, typically black and
white striped elements are necessary, as are cane detectable lower edges on
barriers. Barricades with “feet” extending outward from vertical portions should
be prohibited. Temporary coverings over sidewalk portions such as plywood
panels, must have beveled edges and should be made very conspicuous by high
visibility edges, black or white.
Where accessible pedestrian signals are installed, the site of the tactual and
audible information the the "ped-nex" should be required close to the curb. The
locator tone and vibrating arrow lose much of their usefulness to the vision
impaired traveler who must navigate to the crosswalk from atop the sidewalk or
behind it. At a pedestrian-actuated site, a wheelchair user would access the
push button from a side, or use braking to operate the button from the ramp
slope. Thus, in this situation there is a trade-off benefiting a large group of
disabled pedestrians and inconveniencing some others.
MORE IS NOT ALWAYS BETTER
More of an accessibility feature does not always make for a better accessibility
outcome. Several examples will illustrate.:
1) Wider curb ramps to accommodate two mobility impaired travelers moving side
by side results in even more of the curb removal which diminishes the usability
of the crossing for the vision impaired pedestrian.
2) A very wide crosswalk (one whose side stripes are far apart) is more
difficult to use than a crosswalk with stripes which are reasonably close
together, if the low vision pedestrian can only see one stripe of a broad
3) An elevator with two floor selection panels mounted low is less accessible
for the vision impaired population than one with one panel low for people with
restricted reach and one higher. A Braille user reads with the heel of the hand
below the reading place, and many low vision elevator users read floor
selections visually by looking very closely. In both instances, the presence of
only low mounted panels is an accessibility challenge.
4) Increasing the intensity of artificial lighting can reach a level where glare
or simply the total illumination reduces the functioning of some low vision
pedestrians. Moderate and evenly distributed, lighting is generally recommended
for the accessibility of the greatest number of people.
MYTHS ABOUT LOW VISION
There are some low vision pedestrians with good color perception who like yellow
markings. But, contrary to myth, there are many low vision travelers with little
or no color perception. For them, yellow used on a light surface such as new
concrete, beige floor tiling, or pink marble payers, it is invisible. Yellow can
work for all low vision pedestrians if it is used as the light component
adjacent to a dark component. A yellow detectable warning strip at the edge of a
dark asphalt road can be effective.
Contrary to myth, raised letter text signage is not useful for low vision
pedestrians. While raised numerals are functional, in a dimly lit hotel corridor
on quest rooms for example, no vision impaired person has yet been found who
reads text signage by feeling the raised lettering. The features of text signage
which make the information accessible to the low vision community are- size and
visual contrast. Further, light letters on dark background are preferred if the
characters are also raised. Otherwise, shadows from nearby light sources can
darken the light background inside a character (obscuring the difference between
an upper case “B” and an up case “R” for example.).
It is also myth that gently sloping flares aside curb ramps are helpful to low
vision pedestrians. In fact a steeper sloping side flare can be more visually
detectable, can be more easily avoided by an ambulatory pedestrian with an
unsteady gait and can be less of an obstacle to the placement of other
accessibility elements adjacent to curb ramps. A steeper ramp flare also has the
advantage of removing less full-height curbing near the ramp. Further, the
detectable warning strip on the ramp itself will aid in calling attention to the
location of flares. The Access Board should rethink the standard which calls for
very gradual flares.
VISIBILITY OF STAIRWAYS
Among the low vision population, the single most frequently voiced complaint
about the built environment, is that stairs are hard to see. The Access Board
should rectify the omission in the Final Draft ADAAG released in April of 2002,
and specify high visual contrast marking on the nose of each stair tread on all
steps in the public right-of-way. Embedding a white appearance in the front
three or four inches of each dark surfaced stair tread would greatly improve the
safety of stairways for low vision people traveling independently.
Kenneth L. Stewart
CCLVI Representative to the PROWAAC Member CCLVI Board of Directors