Tarno Coleman, P.E.
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October 28, 2002 |
From: Tarno Coleman, P.E.
Civil Engineering Associate
Marion County Department of Public Works
Marion County Department of Public Works strongly supports the comments and
recommendations found in the document dated
October 14, 2002 submitted by the American Association of State Highway and
Transportation Officials. This document is attached as an appendix of our
submittal. We have the following additional comments:
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1102.2.2 Alterations. Where existing elements or spaces in the public
right-of-way are altered, each altered element or space shall comply with the
applicable provisions of Chapter 11.
EXCEPTION: In alterations, where compliance with applicable provisions is
technically infeasible, the alteration shall comply to the maximum extent
feasible.
Background
The following definition is found in 3.5 Definitions of the ADA Accessibility
Guidelines (ADAAG): "Technically Infeasible. Means, with respect to an
alteration of a building or a facility, that it has little likelihood of being
accomplished because existing structural conditions would require removing or
altering a load-bearing member which is an essential part of the structural
frame; or because other existing physical or site constraints prohibit
modification or addition of elements, spaces, or features which are in full and
strict compliance with the minimum requirements for new construction and which
are necessary to provide accessibility."
While this definition is adequate for buildings, it does not address the issues
arising from problems associated with natural terrain and topography.
Recommendations
Expand the definition. "Technically Infeasible. Means, with respect to an
alteration of a transportation facility, that it has little likelihood of being
accomplished because existing vertical and horizontal limitations would require
violation of existing standards relating to vertical and horizontal alignment;
or because other existing physical or site constraints prohibit modification or
addition of elements, spaces, or features which are in full and strict
compliance with the minimum requirements for new construction and which are
necessary to provide accessibility."
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1102.2.2.2 Prohibited Reduction in Access. An alteration that decreases or has
the effect of decreasing the accessibility of a public right-of-way or site
arrival points to buildings or facilities adjacent to the altered portion of the
public right-of-way, below the requirements for new construction at the time of
the alteration is prohibited.
Background
The wording of this section may imply that adjacent buildings or facilities must
be brought up to the requirements for new construction. An existing private
access to a building may not be in compliance and should not be brought into
compliance at public expense.
Recommendation
Reword the section for clarification. "1102.2.2.2 Prohibited Reduction in
Access. An alteration that decreases or has the effect of decreasing the
accessibility of a public right-of-way to or site arrival points for to
buildings or facilities adjacent to the altered portion of the public
right-of-way, below the requirements for new construction at the time of the
alteration is prohibited.
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1111.3 Location. The alternate circulation path shall parallel the disrupted
pedestrian access route, on the same side of the street.
Background
Requiring that an alternate circulation path is on the same side of the street
creates logistical problems. Pedestrian routes are usually located between the
right of way and the traffic lane. Construction access, or easements, is usually
not available from the adjacent private property due to buildings, etc. This
would require enough right of way space to move the pedestrian access to allow
for 1) the new pedestrian access being constructed, 2) room to allow for
required adjacent construction equipment access, 3) room to allow the temporary
pedestrian access and 4) room for the displaced traffic travel lanes.
Recommendation
Reword the requirement to the following. 1111.3 Location. The alternate
circulation path shall, where feasible as determined by an engineering study,
parallel the disrupted pedestrian access route on the same side of the street.
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1105.2 Crosswalks. Crosswalks shall comply with 1105.2.
...
1105.2.3 Running Slope. The running slope shall be 1:20 maximum measured
parallel to the direction of pedestrian travel in the crosswalk.
Background
This requirement is reasonable at intersections where the natural terrain can
accommodate this transition. An exception needs to be provided where the natural
terrain is so steep that changes in vertical alignment cannot be accommodated
using existing highway design and construction standards.
Recommendation
Reword the requirement to the following.
1105.2.3 Running Slope. The running slope shall be 1:20 maximum measured
parallel to the direction of pedestrian travel in the crosswalk.
EXCEPTION: The grade of the pedestrian access route within a crosswalk shall not
exceed the grade established for the adjacent roadway.
1105.4.1 Length. Where signal timing is inadequate for full crossing of all
traffic lanes or where the crossing is not signalized, cut-through medians and
pedestrian refuge islands shall be 72 inches (1830 mm) minimum in length in the
direction of pedestrian travel.
Background
Reading this section is confusing. Is the purpose to specify the length of
cut-through medians and pedestrian refuge islands or to require all
un-signalized pedestrian crossings to be provided with refuge islands? In areas
with many un-signalized intersections, this would require an additional
obstruction placed in the roadway with corresponding changes in horizontal
alignment.
Recommendation
Delete the reference to un-signalized intersections. 1105.4.1 Length. Where
signal timing is inadequate for full crossing of all traffic lanes or where the
crossing is not signalized, Cut-through medians and pedestrian refuge islands,
where provided, shall be 72 inches (1830 mm) minimum in length in the direction
of pedestrian travel.
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1105.5 Pedestrian Overpasses and Underpasses. Pedestrian overpasses and
underpasses shall comply with 1105.5.
...
1105.5.3 Approach. Where the approach exceeds 1:20, the approach shall be a ramp
48 inches (1220 mm) minimum in width and shall comply with 405. Where the rise
of a ramped approach exceeds 60 inches (1525 mm), an elevator complying with
407, or a limited- use/limited-application elevator complying with 408 shall be
provided.
Background
A pedestrian overpass is not defined. A highway grade separation structure with
sidewalks could be considered a pedestrian overpass or underpass. These
structures typically exceed a 60-inch ramped approach. Placing elevators in
these circumstances would be extremely costly and unlikely to occur in most
cases.
Recommendation
Change the section as follows. 1105.5.3 Approach. Where the approach exceeds
1:20, the approach shall be a ramp 48 inches (1220 mm) minimum in width and
shall comply with 405. Where the rise of a ramped approach exceeds 60 inches
(1525 mm), an elevator complying with 407, or a limited- use/limited-application
elevator complying with 408 shall be provided.
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1105.7 Turn Lanes at Intersections. Where pedestrian crosswalks are provided at
right or left turn slip lanes, a pedestrian activated traffic signal complying
with 1106 shall be provided for each segment of the pedestrian crosswalk,
including at the channelizing island.
Background
Many intersections are un-signalized. A motorist approaching such an
intersection does not expect a signalized stop on an otherwise uncontrolled
intersection.
Recommendation
Marion County concurs with AASHTO's recommendation of "reserving" Section
1105.7, "Turn Lanes at Intersections," until further research can be conducted.
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1106.2 Pedestrian Signal Devices. Each crosswalk with pedestrian signal
indication shall have a signal device which includes audible and vibrotactile
indications of the WALK interval. Where a pedestrian pushbutton is provided, it
shall be integrated into the signal device and shall comply with 1106.3.
Background
There seems to be a lack of consensus among persons with visual disabilities as
to the best method to accommodate their needs. These signal features require
additional initial expense and maintenance. It would be very costly to retrofit
existing signals. Experiments in various urban areas have met with much
resistance from the disabled community.
Recommendation
Marion County recommends "reserving" Section 1106.2 "Pedestrian Signal Devices."
until further research can be conducted and a consensus reached on the
methodology to be used.
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1108 Detectable Warning Surfaces
...
1108.1.1 Dome Size. Truncated domes in a detectable warning surface shall have a
base diameter of 0.9 inches (23 mm) minimum to 1.4 inches (36 mm) maximum, a top
diameter of 50% of the base diameter minimum to 65% of the base diameter
maximum, and a height of 0.2 inches (5 mm).
Background
ADAAG states "3.1 Graphic Conventions. Graphic conventions are shown in Table 1.
Dimensions that are not marked minimum or maximum are absolute, unless otherwise
indicated in the text or captions. 3.2 Dimensional Tolerances. All dimensions
are subject to conventional building industry tolerances for field conditions."
The standard gives no tolerances for dimensions due to normal wear. It could be
argued that any reduction in height of the truncated dome would put out of
compliance for height requirements. "Conventional building industry tolerances"
are of no help due to normal wear.
Recommendation
Modify this section as follows. 1108.1.1 Dome Size. Truncated domes in a
detectable warning surface shall have a base diameter of 0.9 inches (23 mm)
minimum to 1.4 inches (36 mm) maximum, a top diameter of 50% of the base
diameter minimum to 65% of the base diameter maximum, and a height of 0.2 +/-
0.1 inches (5 mm).
Respectfully submitted
Tarno Coleman, PE