October 25, 2002
c/o Scott Windley
U.S. Architectural &
Transportation Barriers Compliance Board
Washington, DC
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 statement.
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 pedestrian public.
ROUNDABOUTS
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 safely.
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 just 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.
LIGHTING
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 directly 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.
"PED-NEX" LOCATION
Where
accessible pedestrian signals are installed, the site of the tactual and
audible information, the "pednex", 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 crosswalk.
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
pavers, 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 guest 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 upper 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 ADAG 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.
Sincerely,
Kenneth L. Stewart
CCLVI Representative to the PRoWAAC
Member, CCLVI Board of Directors