HomeMy WebLinkAboutCrossing Narrative MEF
March 16, 2026
Attention:
Huy Huynh
City of Renton
Development Engineering
425-430-7384
HHuynh@rentonwa.gov
Jones Renton Short Plat
3102 Park Ave N – Renton, Washington
ADA and PROWAG Compliance Analysis
We have studied the pedestrian paths in relation to the intersection of Park AVE N and N 31st ST in
conjunction with the new Road A for the short plat. Specifically we are designing for compliance of the
sidewalks, ramps and crosswalk at the eastern frontage of Park AVE N and bringing the ADA ramps
along the western side of the intersection up to compliance within the “Maximum Extent Feasible” as
required by the relevant standards. The standards being used include the accessibility requirements of the
Americans with Disabilities Act and applicable guidance from the U.S. Access Board Public Rights-of-
Way Accessibility Guidelines (PROWAG), as well as standards applied by the Washington State
Department of Transportation and the City of Renton.
1. Applicable Accessibility Framework
Accessibility requirements for pedestrian facilities in public rights-of-way derive from:
• 2010 ADA Standards for Accessible Design
• PROWAG (Public Rights-of-Way Accessibility Guidelines)
• State and local design standards implementing ADA requirements.
Although PROWAG is formally adopted as guidance rather than a codified federal regulation in
many jurisdictions, it is widely used by state DOTs and municipalities—including WSDOT—as
the accepted technical standard for accessible pedestrian facilities in streets and intersections.
2. Maximum Extent Feasible Standard
ADA regulations recognize that existing physical constraints within the public right-of-way may
limit the ability to meet every technical requirement exactly. Under ADA implementation
principles, accessibility must be achieved to the “maximum extent feasible.”
This concept is applied when:
• Existing roadway grades, drainage patterns, utilities, or right-of-way limitations prevent
full compliance with every dimensional requirement.
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• Strict compliance would require reconstruction of large portions of the roadway beyond
the scope of the improvement project.
The maximum extent feasible standard requires that:
1. All accessibility elements be incorporated wherever possible.
2. Any deviation from ideal geometry be minimized.
3. The resulting facility still provide the greatest degree of accessibility achievable within
the project constraints.
Individual components of the design are discussed below but, as a whole, the current intersection
design:
• Provides fully compliant ADA curb ramps at each corner of the intersection.
• Optimizes crosswalk locations by meeting the maximum running grade requirement,
minimizing deviation in cross slope, maintaining proper street drainage flows, and
providing smooth grade transitions with other traffic flows.
• Includes detectable warning surfaces, signs, and guardrails that fully direct pedestrian
paths.
• Ensures that crosswalks connect directly to ramps.
• Provides continuous pedestrian routes via designed crossing despite limiting the
intersection to three crosswalks due to existing grade constraints.
These features demonstrate that accessibility improvements have been incorporated fully and
wherever physically feasible within the existing intersection geometry and grading conditions.
3. Curb Ramp Design and Placement (PROWAG R304)
PROWAG Section R304 establishes design criteria for curb ramps and blended transitions,
including:
• Maximum running slope of 1:12 (8.33%)
• Maximum cross slope of 2%
• Detectable warning surfaces
• Ramp alignment with crosswalk direction where feasible.
The intersection detail shows directional curb ramps located at each corner, oriented toward the
associated crosswalks.
Directional ramps are consistent with PROWAG guidance because they:
• Fully comply with running and cross slope requirements
• Align the wheelchair travel path with the marked crossing
• Improve orientation for pedestrians with visual impairments
• Reduce the wheelchair travel path by connecting the crosswalks at each corner.
This configuration is widely recognized as best practice for accessible intersection design.
North East Ramp – We looked at widening the ramps at Road A or moving them and adding
ramps. However:
• Moving/adding the ramp east on Road A conflicts with the curb drainage facilities unless
the ramp is moved to the east of both curb drains. However, this conflicts with the stop
bar of the stop sign and moving this would create potential sight distance and other
potential vehicular and pedestrian safety hazards. It would create further road grade
challenges trying to comply with max cross slope as road A far exceeds 2% slope as you
move away from the intersection.
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• When looking at widening this ramp, it was not feasible to achieve max cross slope of
2% without regrading the road, curb and sidewalk to accommodate.
• Widening the ramp quickly conflicts with the curb drain and catch basin on the north side
of Road A and the street light that is just north of the ramp.
• Providing a 4’ landing at the bottom of a wider ramp impairs the drainage design around
this corner that routes the water from Park Ave to the catch basin on the north side of
Road A.
• Providing a 4’ landing at the bottom of a wider ramp increases the abruptness / slope of
the transition out of the landing creating an “edge” in the road grade when traveling
across the crosswalk near this wider landing.
• Given all of these design challenges with widening or moving this ramp, the original
proposed design represents the most feasible solution, it is the most common for
situations where there is moderate surrounding road grade as it fully complies with
PROWAG requirements while minimizing challenging transitions back to road grade and
maintaining adequate drainage paths. The South East ramp has more flexibility due to
separation of utilities and convenience of flatter grade there, however we are proposing to
match the design of the North East ramp for consistency.
Northwest Ramp:
• Providing a compliant ramp at the corner creates a situation where the southern edge of
the ramp is 12” to 18” above the existing road grade along N 31st. Transitioning this back
to road grade pushes drainage toward the center of the street, exacerbates the slope of N
31st ST (which is already steeper than road standards) and would require extensive road
re-grading, surfacing, curb, drainage and sidewalk revisions that far exceed the scope of
bringing an existing ramp to current PROWAG standards.
• Applying the best design within maximum extent feasible, we are proposing to move the
ramp slightly to the north of the corner where the grade of Park AVE N is more
conducive to achieving the necessary ramp cross slope. It also helps provide a crosswalk
to the east that meets running slope and cross slope standards (as described below). And
it maintains a sufficient distance from the stop sign / stop bar to avoid pedestrian /
vehicular conflicts. We are proposing to saw cut 2’ into the street and regrade / rebuild a
curb that will provide a smooth landing at the bottom of the ramp and a smooth road
transition and drainage flow to the gutter. We will continue the curb around the corner to
help transition the grade between the road, shoulder and sidewalk and maintain the
drainage route.
• It is not possible to provide a compliant wing/sidewalk south of this ramp as the slope of
N 31st and associated shoulder exceeds this slope. Due to this, and the challenges with
providing a crosswalk that are described below, we are proposing to terminate the
sidewalk at the ADA ramp and direct pedestrian across the intersection where the newly
built infrastructure provides an adequate and compliant route. The termination includes
guardrail and signage to discourage travel toward non-compliant grades and direct
pedestrians to the accessible route..
Southwest Ramp:
• Widening this ramp would significantly exceed maximum cross slope and landing
requirements, or it would stick up well above the existing street level on the north side of
the ramp, creating issues similar to the North West ramp that was built and we are
proposing to re-configure due to its deficiencies. This condition makes wider ramps or a
sidewalk rounding N 31st unachievable in this situation as PROWAG prioritizes meeting
slope requirements over providing additional ramp width where the two are in conflict.
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• The slope of N 31st and associated shoulder makes it impossible to achieve a fully
compliant ramp at the corner extend a compliant wing or sidewalk to the north. Due to
this, and the challenges with providing a crosswalk that are described below, we are
proposing to terminate the sidewalk at the ADA ramp and direct pedestrian across the
intersection where the newly built infrastructure provides an adequate and compliant
route. The design for this termination includes a guard rail and signage to protect
pedestrian traffic from the non-compliant grade transition and direct them to use the
compliant crosswalks.
4. Accessible Pedestrian Route Requirements (PROWAG R301 / R302)
PROWAG requires that public rights-of-way include a continuous accessible pedestrian route
connecting sidewalks, curb ramps, and crossings.
Key requirements include:
• Minimum clear width of pedestrian access route
• Running slope not exceeding 5%
• Cross slope not exceeding 2%
• Firm, stable surfaces
• Continuous connection between pedestrian facilities.
The intersection layout shown in the exhibit provides:
• Sidewalk connections approach each corner of the intersection.
• Fully compliant curb ramps transition between sidewalk and roadway elevation.
• Marked crosswalks connect ramp landings across each leg of the intersection.
• Crosswalks have running slopes do not exceed 5% and cross slopes that do not exceed
3%. While the cross slopes do exceed the 2% guideline, it is only in a couple isolated
locations and never exceed 3%. his remains a safe crossing configuration and is
consistent with the maximum extent feasible given the existing road configuration.
West Crosswalk:
• The road grade of N 31st becomes very steep abruptly within the western edge of the
intersection. In order to get even close to the 2% cross slope requirement, the entire
intersection would need to be lowered requiring extensive regrade up and down Park
AVE and Road A or N 31st would have to be lifted, creating an even steeper road
exceeding road standards. Both of these solutions would be extensive, they would reduce
compliance of the adjacent ADA infrastructure and would far exceed the required scope
of work to improve our frontage and upgrade the intersection ramps, it is inconsistent
with the drainage and grading approved and built in our engineering permits, and it
exceeds the provisions of PROWAG to achieve ADA goals while working with the
existing conditions.
• Once we build an ADA compliant ramp, the landing at the northwest corner would be
above the centerline of the N 31st at the intersection. This would require further drainage
design and infrastructure that moves this design further outside the goals of PROWAG
and the maximum extent feasible provision.
• Therefore, we are proposing to divert pedestrian traffic to use the crosswalks on the east
side of the street by terminating the sidewalk, providing a guardrail and signage at the
terminations. Essentially, we are achieving maximum compliance for the proposed
crossings, focusing traffic towards these safe crossing routes, maintaining a continuous
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accessible path of travel through the intersection, which is all consistent with PROWAG
accessible route requirements.
5. Crosswalk Connectivity and Alignment (PROWAG R206 and R302)
PROWAG requires that pedestrian crossings connect accessible routes on both sides of the street.
The design includes:
• Marked crosswalks across each intersection leg
• Crosswalks aligned with curb ramp openings
• Direct ramp-to-ramp pedestrian travel paths.
These features ensure pedestrians with mobility impairments can travel across the intersection
without leaving the designated pedestrian route, satisfying PROWAG connectivity requirements.
6. Conclusion
The intersection improvements shown on the design provide a pedestrian crossing system that:
• Maintains a continuous accessible pedestrian route
• Incorporates directional ADA curb ramps
• Provides detectable warning surfaces
• Connects ramps through marked crosswalks
• Implements accessibility improvements to the maximum extent feasible
These elements collectively satisfy the accessibility requirements of the Americans with
Disabilities Act, as interpreted through PROWAG and implemented by Washington State and
City of Renton design standards.
Thank you,
CORE DESIGN, INC.
Flavio Bainotti
Project Manager
425-885-7877
fbainotti@coredesigninc.com