|August 8, 2002|
Attached are comments on Draft Guidelines for Accessible Public Rights-Of-Way, June 14, 2002. These comments are made on the basis of my position with the City of Abilene.
I am currently the Traffic & Transportation Administrator for the City of Abilene. I have been employed by the City of Abilene for 24 years in several different professional positions in Traffic Engineering and Public Works. I served on the City’s team that prepared our Transition Plan for implementing the Americans With Disabilities Act in the early 1990’s. I hold a Bachelor of Science degree in Civil Engineering and a Master of Engineering degree in Civil Engineering from Texas A&M.
Thank you for the opportunity to provide these comments.
Traffic and Transportation Administrator
COMMENTS ON DRAFT GUIDELINES FOR ACCESSIBLE PUBLIC RIGHTS OF WAY
JUNE 14, 2002
In Section 1101.3, revise the definition of the term “sidewalk”.
The definition is too broad because it includes any improvement for use by pedestrians. There are some improvements to the right-of-way that facilitate use by pedestrians that should not be included in the definition of a sidewalk. The following are some examples of such improvements that have been constructed by the City of Abilene: grading of rough or steeply sloped sections of the right-of- way to produce a “level” and “smooth” surface for pedestrians and constructing base material shoulder. Also, the City of Abilene allows property owners to pave the parkway (right-of-way between the curb or edge of pavement and the property line). This is often done by business owners so that they do not have to maintain the parkway. It produces a surface that is firm and relatively smooth although not usually flat. It is a better walking surface for pedestrians than bare ground; however, it is not constructed for that purpose and it is not a sidewalk in the normal understanding of the term.
The general concept of a sidewalk is that it is a hard surface (portland cement concrete, asphaltic concrete, brick, concrete payers, etc.) path constructed for use by pedestrians and sometimes bicycles. A path for pedestrians constructed of gravel, crushed rock, or other aggregates does not constitute a sidewalk. An improved earthen path, i.e., level and smooth or even compacted, is also not a sidewalk.
The following is a recommended definition for sidewalk:
Sidewalk. A path with a firm, stable surface constructed for use by pedestrians within that portion of a public right-of-way between the curb line or lateral line of a roadway and the adjacent property line.
2. In Section 1101.3, revise the definitions of “channeling island” and “splitter island”.
The definition of a channelizing island needs to be more robust and should incorporate the key concepts from the AASHTO design guidelines. Since a splitter island is a channelizing island that is used at a roundabout (see definition of roundabout), the splitter island definition can reference the channelizing island definition.
The following definitions are recommended:
Channelizing Island. At an intersection, the area defined by curbs, pavement markings, or unpaved areas formed by pavement edges for the purpose of directing traffic into defined paths, providing refuge areas for pedestrians or providing locations for traffic control devices.
Splitter Island. A channelizing island that separates entering and exiting traffic at a roundabout.
3. In Section 1101.3, revise the definition of “crosswalk”.
The portion referencing the point of measurement is confusing. It is also unnecessary. The only measurements associated with a crosswalk, i.e., the 48- inch minimum clear width of the pedestrian access route (Section 1103.3) and the 96 inch minimum width for marked crosswalks (Section 1105.2.1), do not reference the curb line or edge of roadway. If the intent of the reference to a measurement was to require the crosswalk to be completely on the sidewalk side of the curb line, then it should be stated in those terms.
Where there is sidewalk on only one side of the street, the requirement for the crosswalk to be at right angles to the street being crossed creates problems when streets intersect at other than right angles. In that situation, pedestrians will cross parallel to the street that intersects the street being crossed. This is the normal location for a crosswalk. If the intersection angle is significantly different than 90°, the requirement for the crosswalk to be at right angles to the center line of the street being crossed will result in the two types of problem situations shown in the attached Figure A. The sidewalk in the northwest corner would project into the intersection. The sidewalk in the southwest corner would project to the opposite curb at a considerable distance from the intersection.
The issue of directing pedestrians into the crosswalk can be handled in the same manner as cut-throughs in medians and refuge islands (Section 1105.4). That is, require the edges of the ramp or landing to be aligned with the direction of the crosswalk for a length of 24 inches.
The following is a recommended definition of a crosswalk:
Crosswalk. Any portion of a roadway at an intersection or elsewhere that is distinctly indicated for pedestrian crossing by lines or other markings on the surface; that part of a roadway at an intersection that is included within the extensions of the lateral lines of the sidewalks on opposite sides of the roadway; or in the absence of a sidewalk on one side of the roadway, the part of the roadway included within the extension of the lateral lines of the sidewalk parallel to the street that intersects the street being crossed.
4. In Section 1101.3, add a definition for “blended transition”.
The guidelines do not have sufficient information for an clear understanding of the term “blended transition”. The supporting material indicates that it is an alteration in grade to the sidewalk and/or the pavement that produces a situation where some portion of the curb return is flush with the pavement at the crosswalk. It also appears that only the flat (1:48 slope maximum) portion that abuts the edge of pavement is the “blended transition”, while the portion connecting to the sidewalk is either ramps or a curb ramps.
If these discernments are correct, then the following is recommended definition for a blended transition. If these discernments are not correct, then obliviously a different definition is needed.
Blended Transition. A portion of sidewalk at the intersection curb radius that is flush with the abutting pavement and that is created by altering the grade of the sidewalk and/or the pavement.
5. In Section 1101.3, add a definition for “slip lanes”.
The term “slip lane” is not used in this part of the country and the term is not used in the AASHTO Policy on Geometric Design. The term appears to refer to some type(s) of exclusive use turn lanes. Exclusive use turn lanes are used to increase capacity and/or to improve safety of traffic operations at intersections. The operational characteristics are influenced primarily by two key elements: the method used to separate the turn lanes from the adjacent through lane and the type of control used.
For right turn only lanes, the following methods are used to separate the turn lane from the adjacent through lane in Abilene.
• Single solid lane line.
• Small channelizing island of pavement markings, typically about three to five feet wide at the crosswalk.
• Small raised channelizing island, typically about three to five feet wide at the crosswalk.
• A corner island about 10 to 15 feet on the sides parallel to the through lanes, usually a raised island defined by curbs.
• A large corner island about 50 feet ± on the sides parallel to the through lanes, either a raised defined island defined by curbs or a flush island.
For right turn only lanes, the following are some forms of control used in Abilene.
• Signal control of through lanes with signal control of turn lane.
• Signal control of through lanes with yield control of turn lane.
• Stop control of through lanes with stop control of turn lane.
• Stop control of through lanes with yield control of turn lane.
• No control of through lanes and no control of turn lane.
It is not clear from the guidelines if the term slip lane refers to all exclusive use turn lanes or if it is a special type of exclusive use turn lane. If it is a special type, then the characteristics (geometric and/or control) that distinguish it from exclusive use turn lanes in general need to be clearly defined.
6. In Section 1102.1, insert the following statement:
These guidelines do not require the provision of sidewalks, street crossings, street furniture, parking, or other pedestrian elements where none are intended. These guidelines address such elements only where they are provided as part of construction or improvement projects.
7. Section 1102.2 refers to “existing public rights-of-way”. However, based upon the context, including the Section 1102.1 reference to “facilities in public rights-of way”, Section 1102.2 is actually referring to “existing facilities in public rights-of way”. To correct this, insert the words “facilities in” between the words “existing” and “public” in the following locations:
• Title of Section 1102.2
• First sentence of Section 1102.2
• Second sentence of Section 1102.2
• First sentence of Section 1102.2.1
8. Section 1102.3, requires an alternate circulation path to be provided whenever the existing pedestrian access route is blocked. This requirement is excessive.
Construction, alternation, and maintenance can result in blocking both vehicular and pedestrian paths. In an urban environment, a specific alternative path for vehicles (a detour) or for pedestrians is often not provided. Where streets with sidewalks are in a closely spaced grid, alternative paths exist, It is usually more practical for short duration activities (up to several days) to allow motorists and pedestrians to find their own alternative paths than to try to direct them to a specific route. For example, recently the City of Abilene allowed full closure of one block of a street in the downtown area for several days due to a short duration construction activity (the erection of steel on a building adjacent). The street was closed to vehicle use and the sidewalks were closed to pedestrian activity. Given the closely spaced grid street pattern and the short duration of the project, signing of a detour for vehicles was not required and creation of a pedestrian path through the site was not required. Under the guidelines, an “alternate circulation path” would have been required because the existing pedestrian access route was blocked. However, it was not practical to provide a specific alternative path for pedestrians through or adjacent to the site.
The provision for an alternate circulation route should take into account factors other than the fact that a pedestrian access route is blocked, just as the MUTCD does in Part 6 relative to construction and maintenance activities. Factors to consider are the duration of the temporary conditions and the availability of existing alternative routes in the vicinity. An alternate circulation path in compliance with the guidelines should only be required if an alternate circulation path is provided for non-ADA pedestrians.
9. In Section 1102.5, correct the last phrase to read “pedestrian access routes” instead of “pedestrian accessible routes”.
10. In Section 1102.5.2, the second sentence is not clear. The 12-inch dimension is not related to a specific element such as height or width or distance between poles. A similar situation is addressed in Section 307.2. There the phrase “and the clear distance between posts and pylons” precedes “...is greater than 12 inches...”. Inserting that phrase into the second sentence would clarify the situation. A figure would help to explain this.
11. The requirements of Sections 1102.5.1, 1102.5.2, and 1102.5.3 are covered in
Sections 307.2, 307.3, and 307.4. Therefore, Sections 1102.5.1, 1102.5.2, and
1102.5.3 should be deleted and in Section 1102.5 reference should be made to
Sections 307.2, 307.3, and 307.4. The reference to other sections of the ADAAG
instead of repeating them is used throughout the Accessible Public Rights of
12. In Section 1102.14, the phrase “where on-street parking is provided” is too vague. If it refers only to locations where parking spaces are marked on the street, then it should state: “where on-street parking is marked on the street”. If it includes locations where on-street parking is allowed even though it is not marked, then it should state: “where on-street parking is allowed on the street
13. In Section 1102.14, the requirement for accessible on-street parking should only apply to locations where parking spaces are marked (or designated) on the street. Requiring accessible on-street parking where on-street parking is allowed but not marked is excessive. For example, most residential streets in Abilene are 36 to 40 feet in width. This width allows for two-way traffic and on-street parking on both sides. On these streets, parking is allowed but parking spaces are not marked. To require an accessible space on each block face in such a circumstance is unreasonable.
14. In Section 1102.14, the requirement for one accessible space per block face is excessive.
The number of parking spaces in a block face can vary greatly due to length of block face, size and number of driveways, and the orientation (angle) of the parking. For example in the downtown area of Abilene, there are 99 block faces on which on-street parking spaces are marked. The number of spaces per block face ranges from 2 to 16 with an average of 9. Converting one non-accessible space per block face to an accessible space to meet the requirement of one per block face would result in 6% to 50% of the total spaces for a given block face being accessible. The total number of marked spaces is 881. At one accessible space per block face the resulting 99 accessible spaces would be 11 % of the total spaces. The true impact is even greater, since typically a second parking space is lost when a parking space is converted to accessible because an adjacent space is converted to the access aisle.
In Texas, parking spaces designated for the disabled with the international symbol (as required for accessible spaces) can only be used by properly designated vehicles transporting persons with disabilities. Vehicles meeting this requirement do not constitute 11 % of the vehicles that park on-street. Also, persons with disabilities may park in spaces that are not designated for the disabled (and they do so if they do not need the access aisle next to them, e.g., someone with a breathing disability that limits their walking distance).
A different requirement for on-street accessible spaces is needed. One alternative is to require an accessible space for each block face except for block faces with a small number of marked parking spaces, e.g., a block face with less than 20 spaces. Another alternative is to require one space for each pair of adjacent block faces. A third alternative is to require one accessible space for every X spaces, e.g., 25 or 50, along contiguous block faces.
The following is a recommended replacement for Section 1102.14:
1102.14 On-Street Parking. Where on-street parking is marked on the pavement, a minimum of one accessible on-street parking space shall be provided for each pair of adjacent block faces but not less than one accessible space for each 50 on-street parking spaces. Accessible on- street parking spaces shall comply with 1109.
15. Section 1104 only address perpendicular curb ramps, parallel curb ramps, and blended transitions.
The titles and descriptions of perpendicular curb ramps and parallel curb ramps imply that these are to be placed within a straight section of the street curb. Therefore, it is presumed that diagonal and corner type curb ramps are not allowed. If perpendicular and parallel curb ramps can only be placed in sections of straight curb, i.e., not within the curb return, then this could place them at an unacceptable distance from the intersecting street where there are large curb returns.
The use of the diagonal and corner type ramps should not be precluded. In Abilene, typical intersection curb return radii are 20 to 25 feet and on major streets 30 to 40 feet. Parkways are narrow, usually only 10 to 12 feet. Crosswalks are typically within the first 15 feet of the projected curb line of the street parallel to the crosswalk. This results in curb ramps that fall within the curb return (see Figure B). Functionally this is preferable to placing them beyond the curb returns.
16. Section 1104.2.3. on blended transitions has only the requirement for slope and for compliance with the common elements in Section 1104.3. In the drawing of a blended transition in the supplemental information, it appears to be similar to the landing associated with the parallel curb ramp. If that is true, then there should be a requirement that the blended transition be large enough to contain a square of 48 inch by 48 inch minimum.
17. In Section 1104.3.7, the following elements concerning the required “clear space” are unclear.
a. The clear space is required to be “beyond the curb line”. If this means within the pavement area of the street, then the requirement should be stated as such.
b. The clear space is required to be “outside the parallel vehicle travel lane”. It is not clear to what the vehicle travel lane is to be parallel. This reference could be to the street parallel to the crosswalk or to the street parallel to the curb line being crossed.
c. If the clear space is indeed on the pavement side of the curb lines, the rationale for such a requirement is unclear. It would be safer to have the clear space on the sidewalk side of the curb line. If the clear space is on the sidewalk side of the curb line, then it appears that it could be the same area as the landing at the bottom of a parallel curb ramp on even a portion of the blended transition.
18. Section 1105.3 uses the term “pedestrian signal phase timing”. However, what is being described is what the MUTCD refers to as the “pedestrian signal clearance time”. Since the MUTCD is the official document related to traffic signals (and other traffic control devices), the term should be changed to “pedestrian signal clearance time” to make it consistent with the MUTCD
19. Section 1105.3 requires the pedestrian signal clearance time to be based upon a pedestrian walk speed of 3.0 feet per second. This is an excessive requirement for application at all traffic signal installations. The advisory committee’s recommendation of 3.5 feet per second is a better overall requirement than the 3.0 feet per second.
The MUTCD currently uses a pedestrian walk speed of 4.0 feet per second with a recommendation to use a slower speed if circumstances warrant. This allows for engineering judgement. At signal locations where there are no pedestrian signals, the pedestrian clearance time still must be considered. In this case, the MUTCD requirement should be used. At signal locations where pedestrian access routes do not exist, the MUTCD requirements should be used.
The following is a recommended replacement for the first sentence of Section
At signal locations with pedestrian access routes, the pedestrian signal clearance time shall be calculated using a pedestrian walk speed of 3.5 feet per second (1.07 m/s) maximum.
20. Section 1105.3 requires calculation of pedestrian signal clearance time to be based upon the entire length of the crosswalk plus the length of the curb ramp. The MUTCD currently recommends that the pedestrian clearance time be sufficient for pedestrians to travel the distance from the curb to the middle of the farthest traffic lane. Basing the pedestrian clearance on the total crosswalk distance within the street is not unreasonable, although the MUTCD recommendation is sufficient for many situations. However, requiring the inclusion of the curb ramp length in the distance for calculating pedestrian clearance time is unnecessary and can be excessive if the ramps are long. Also for parallel curb ramps, there is a landing before the ramp begins.
21. Section 1105.6.2 requires pedestrian signals for crosswalks at roundabouts. This is an unreasonable requirement.
Roundabouts are intersections that by design are intended to operate without the need for a traffic signal for vehicular control. The very nature of a roundabout makes installing signal control for vehicles at a roundabout unreasonable. Although signal control for entering vehicles can be reasonably accomplished, signal control for exiting traffic is impractical. This is due to several factors including: the need for visibility of the signal heads for the controlled movement and the lack of storage space for stopped vehicles within the roundabout.
The features that make roundabouts a desirable form of intersection control for vehicular traffic can pose a problem for pedestrians. Instead of crossing the traffic lanes near the circular portion of the roundabout, it would be safer to have pedestrian crossings of the approach/departure roadways at a distance from the roundabout. Although it results in a longer distance for pedestrians, this “mid block” location provides improved visibility of the crossing location for the motorist.
22. Section 1105.7 requires pedestrian signals for crosswalks crossing right or left turn slip lanes. Because there is no definition of a slip lane, it is difficult to comment on all aspects of this requirement. However, the following issues can be addressed.
This requirement makes no distinction between right and left turn lanes at signalized intersections and those at non-signalized intersections. Therefore, this requirement would force the signalization of intersections that otherwise would not need a signal and which do not meet the signal warrants of the MUTCD This is an unreasonable requirement.
The geometric design of some exclusive use turn lanes is such that signalizing them will be difficult, similar to the problems associated with signalizing roundabouts.
23. In Section 1111.3, the alternate circulation path is required to be parallel and on the same side of the street as the disrupted pedestrian access route. The requirement to be the same side of the street is often impractical, if not impossible.
For example, assume that a construction project occupies the parkway and the adjacent parking lane of a street, and as a result, a pedestrian access path in the parkway is blocked. It is more practical and safer to provide the alternative circulation path on the other side of the street than it is to shift traffic lanes over to create an alternate circulation path between the construction and the traffic lanes.
This portion of the requirement, i.e., “on the same side of the street”, should be deleted.
24. The term “barrier” is used in Section 1220.127.116.11 and Section 1105.6.1. No information is given relative to what constitutes an acceptable barrier. If the barriers in Section 405.9.2 that serve as edge protection for ramps are acceptable barriers, then these should be referenced. If these are not acceptable, then the parameters of acceptable barriers must be given.
Traffic & Transportation Administrator
City of Abilene
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