James D. Perkins, P.E.
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October 28, 2002 |
James D. Perkins, P.E.
Senior Engineer
Washington County
I have the following observations and comments on the Draft Guidelines for
Accessible Public ROW (June 17, 2002).
1102.4 The guidelines state "Where sidewalks are provided, they shall contain a
continuous pedestrian access route complying with 1103." This states that all
sidewalks shall be accessible. What is the reasoning for including 1102.10
(stairs), since stairs are an inaccessible item for people in wheelchairs?
1102.5.3.1 For areas with reduced vertical clearance the draft
guidelines state that "The leading edge of such guardrail or barrier shall be
located 27 inches (685 mm) maximum above the finish floor or ground." With the
maximum height set at 27" with no minimum height it is conceivable to create a
hazardous obstruction or tripping hazard. A section for standard ADA barriers is
needed in the draft guidelines.
1104.2.2.4 The draft guidelines state that "...drop-offs at diverging
segments shall be protected with a barrier." No definition of a barrier is
given. A section for standard ADA barriers is needed in the draft guidelines.
1104.3.7 What is the need for a clear space beyond the curb line?
This has greater impacts than will probably first be realized. It adds to
pedestrian signal times and adds complexity to drainage and roadway layouts.
1102.5.3.2 The draft guidelines state that for roundabouts "Continuous barriers
shall be provided along the street side of the sidewalk where pedestrian
crossing is prohibited." No information on the barrier is given with the
exception of the bottom rail. A section for standard ADA barriers is needed in
the draft guidelines. What is the extent of the needed barriers? Are they
required even at curbside sidewalks?
1105.6.2 The requirement for pedestrian activated traffic signals at splitter
islands is inconsistent with the exception in 1106.2.1.
1105.7 Currently many sliplanes are installed at unsignalized
intersections. Requiring all slip lanes to be signalized will effectively negate
their use on many intersections and thus increase traffic congestion and
construction cost. If a jurisdiction decides on the need for an added turnlane
according to the guide they will either install a signalized slip lane or add
another lane of traffic and still create an unsignalized intersection. If an
unsignalized intersection is chosen the net result is added cost for no gain
from installing an unsignalized slip lane would provide the same net affect for
pedestrians. This section also requires a pedestrian activated signal at all
splitter islands. This is not consistent with the exception in section 1106.2.1.
1108.1.3 I am deeply concerned about detectable warnings having a
visual contrast of dark-on-light. A person with little visual acuity will
perceive a dark area as a hole or pit and thus avoid the dark area or accept
that a dark area is a detectable warning area and end up walking into a pit
(i.e. an open utility vault). Allowing dark-on-light is only setting up the
public for some dangerous situations.
The following comments all have a common theme- that is many of our streets and roadways have slopes and grades to them.
In 1103.5 the pedestrian access route can follow the road grade on a steeply sloped street. How does this mesh with 1105.5.3 where elevators or lifts are required at underpasses and overpasses when the rise is greater than 60"? The reason given for the elevator or lift requirement is that lengthy ramps often are unusable due to the exertion required in maneuvering wheelchairs upslope. Following this logic all sidewalks (following the roadgrade) with slopes greater than 1:12 (8%) would require elevators and lifts- clearly infeasible. It seems reasonable to propose that many of the requirements of the proposed rules (i.e. 1103.4 etc.) should be eased in areas of steep terrain.
1103.5 This cannot be consistently met in sloping terrain where 1104.2.1.3
is met. If the sidewalk is at a running grade greater than 1:12 then either the
upside walk or downside walk will have to be steeper than 1:12 or steeper than
the running slope of the road in order to meet the top landing of the ramp.
1104.2.2 This cannot be met in sloping terrain where 1104.2.1.3 is met. See 1103.5 above for reasoning.
1104.2.3 This cannot be met in sloping terrain where 1104.2.1.3 is met. See 1103.5 above for reasoning.
1105.2.2 Requiring a maximum 2% cross slope on crosswalks is often infeasible
in sloping terrain. As an example assume a crossing street with a rather benign
5% grade and the intersection sloped at 5%. Requiring crosswalks to have a
maximum 2% cross slope would require the whole intersection to achieve a 2%
slope (due to restrictions on vertical curves). With a roadway width of 50' (3
lanes with bike lanes) and 30' curb radii the distance outside to outside of the
crosswalks will be about 93' apart and the grade difference between the constant
5% grade and the 2% intersection grade would be about 1 ½'. This would require
either ROW acquisition or retaining wall to contain the grade difference. The
effect of the 2% cross slope would also extend for hundreds of feet from the
intersection due to the required vertical curve limits imposed by national road
design practice.
Thank you for the opportunity to comment.