|October 28, 2002|
In a separate e-mail I will be sending a Microsoft Word version of
these comments with formatting as an attachment, which you may find more
convenient to use. I will also mail that document as a letter to the Access
My original intent in responding to the draft standards was that I had been informed that the Board would be establishing 60” as the minimum width for sidewalks. I am glad to see that the Board has instead recommended a minimum width of 48”. As discussed below, I believe that the wider width would result in fewer sidewalks being constructed, and would be severely counter-productive.
However, the idea of requiring wider sidewalk widths is consistent with a general fault of many of the proposed guidelines. The guidelines appear to have been drafted to address common problems experienced in cities by different types of persons having disabilities, or at intersections on very heavily traveled arterial highways. However, the regulations of the Access Board will extend throughout the nation and will be applied on streets, roads, highways, lanes and other public rights-of-way in rural, exurban, suburban and neighborhood environments, not just in city centers. In many of these environments, some of the mandatory standards presented would be either inappropriate or, as in the case of 5’ sidewalks, counter-productive by discouraging roadway design practices that soften the roadway environment and make roadways more convenient for all non-motorized users.
I encourage you to critically evaluate the effect and appropriateness of these standards in environments where the frequency and intensity of conflicts between different users can be anticipated to be substantially less than in city centers and similar intensely used areas.
My comments are as follows:
Cross slope. Cross-slope is not usually called superelevation. Superelevation is a roadway design treatment that adjusts the cross slope to mitigate the impact of curvature. I recommend that the second sentence be deleted.
Similarly, if you must define superelevation, you should define it using language that in fact is descriptive. I looked for a definition in both AASHTO’s Policy on Geometric Design and ITE’s Traffic Engineering Handbook but found none. I suggest something like the following:
Superelevation – an adjustment to the cross slope of a traveled way that is introduced to mitigate the outward centrifugal force created by a horizontal curve. Superelevation is conventionally termed “banking”.
However, I question whether a definition is required. You may wish to conduct a search to determine if it is used in the text of the regulations.
Note that if you do use the term, you should use an all-inclusive term such as traveled way rather than roadway or highway. Superelevation can be introduced on paths and sidewalks as well as highways. Conversely, reverse superelevation, or banking in the reverse direction of a curve, can pose a special problem for persons in wheelchairs. Unfortunately, it is relatively easy to inadvertently introduce reverse superelevation along a pedestrian access route if the designer is not attentive.
Stairs. This section should be amended to provide guidance regarding where the use of stairs may be appropriate in public rights-of-ways. The guidance should strongly discourage the use of stairs except in situations where the natural grade clearly necessitates their use of stairs. Thoughtless designers who introduce unnecessary stairs into public the right-of-way are being cruel to all users.
When stairs are introduced, they should be located out of the preferred pedestrian route so that most users will be attracted to a route without barriers.
On-street parking. On-street parking requirements should only apply in locations where the parking is used by the general public in a mixed use environment and where the parking supply is constrained.
On most residential streets in suburbs, and many other streets, parking is permitted but only lightly used. I feel certain that most persons that might seek an accessible space in a confined and shared parking environment would seek to use a parking space most convenient to the specific destination in an unconfined environment. This could include blocking the driveway at the intended destination.
In areas surrounding Lawrenceville, municipalities use accessible parking regulations to regulate spaces in front of homes or businesses that have individuals who regularly need such a reservation. This more flexible approach helps to protect proximity of parking for persons who need such protection. At locations where the general public is being encouraged to park, such as in a village center, the approach proposed in the draft regulations is currently followed.
This section should establish conditions under which it should be implemented. This could either be a warrant based system using a variable associated with constrained parking demand, or it could be based on engineering judgment. Note that an approach frequently followed is to supply accessible spaces in convenient segregated off-street locations and allow the on-street supply to be used for persons not requiring accessible design. Where practical, this approach usually results in superior design.
Proposed 1102.14 is an example of a regulation aimed at a dense urban environment that would be impractical or counter-productive in other environments. It should be more narrowly drafted.
I strongly endorse the use of 48 inches as the minimum clear width of the pedestrian access route in most situations. At the same time, there clearly are situations where higher pedestrian volumes, or the likely use of pedestrian routes by persons in wheelchairs, will require a greater width.
Some language should be included to provide guidance where such additional width is required – for example surrounding hospitals, in retail centers, near nursing homes or other places that serve persons with disabilities, etc. A methodology should be presented for determining the amount of additional width required and the extent of the surrounding area within which widening should occur.
The minimum clear width should be enlarged to six feet if the pedestrian access route immediately abuts a curb. (Note: a curb represents a vertical edge that is a hazard not only for persons in wheel chairs and blind persons but for all pedestrians. Slipping off of a curb can cause serious injury. A requirement that sidewalks be widened if they abut a curb is relatively standard.
Add a section on edges.
This section should include specific guidance regarding the treatment of edges adjacent to pedestrian access routes. Routes that abut a vertical surface such as a wall should be widened by at least one foot.
The surface of a pedestrian access route should not directly abut an edge. Language similar to 405.9.2 should be provided describing edges and design approaches presented to indicated the protection that should be provided.
I recently was walking along a bridge over a river that was constructed within the past three years. The wooden sidewalk has railings. However, the 5’ boards that create the sidewalk terminate with no edge treatment or curb. Instead, a vertical drop to the river is presented at the edge. The user of a wheelchair could readily have a wheel caught in this edge, would be thrown against the railing and would be unable to extricate himself or herself. I will be working to correct this instance, put the regulations should prohibit it from occurring along a pedestrian access route.
Grade Exception. The proposed regulations allow for the pedestrian access route to be steeper than the grade of the adjacent roadway. I understand that there may be unique conditions in which this may be appropriate, in particular to create level platforms at doorways. However, the blanket exception, as worded, goes to far.
In our area, and in many other suburban areas, designers of late have become very fond of introducing unnecessary vertical and horizontal curvature into sidewalks to make them more appealing to motorists. The vertical curves especially are an unwarranted and unnecessary burden to all pedestrians, and are a viciously cruel insult to persons in wheelchairs. Your regulations should include language requiring designers to keep pedestrian access routes as flat as possible and permitting exceptions only where other accessibility requirements require an adjustment.
In addition, designers should be encouraged to introduce modest horizontal diversions, where appropriate, to reduce the grade of a pedestrian access route. Horizontal diversions should also be encouraged along routes that have a grade in excess of 1:20 prior to any conflict points.
Pedestrian Access Route and stairs. As indicated above, stairs should be kept out of the pedestrian access route. Where stairs may be desirable, the pedestrian access route should be designed in such a fashion that the route that employs stairs can be perceived as a secondary route.
Where grades make steps unavoidable and an elevator is required, the elevator should be located in a convenient and obvious location requiring little circuitous travel. Standards are needed, appropriate for public environments.
Cross slope. The reason for exempting mid-block crossings from the maximum 1:48 slope should be explained. I am assuming that at a mid-block crosswalk, the cross-slope of the ramp should be the same as the slope of the gutter so that the pedestrian route will not be warped. If that is the intent, it should be stated.
Width. I strongly encourage you to require curb ramps or blended transitions to extend for the full width of a crosswalk, if marked, or the full width of the extending sidewalk if no crosswalk is marked.
A person needing the use of a curb ramp should not have to search for its location but instead assume that a transition free of vertical change in level will be available at the roadway edge. In a city, fighting to move at right angles to the flow of pedestrians to the available curb ramp can be difficult and/or dangerous. In suburban areas, the crosswalk should provide visual guidance regarding the curb ramp location. See below regarding crosswalk width.
Grade breaks. As I understand this section, it applies only to grade breaks in curb ramps and blended transitions. The first sentence indicates that grade breaks are not permitted at curb ramps, blended transitions, etc.; the second sentence says that when they do occur they shall be flush. Either grade breaks are permitted or they are not permitted.
I obviously don’t understand the meaning of flush in the second sentence, and it is not defined. I think that you mean that there shall be no change in level at a grade break.
From a practical perspective, this will be very difficult to achieve. With differential settling, differences of less than ¼ inch are bound to occur. Furthermore, unintentional grade breaks are likely to evolve. Do these exceptions become instantly in contravention of the regulations?
Changes in level. Similarly, although a project may be initially designed to result in no changes in level, the requirement that different materials be used in the sequence of devices described, curb ramps, landings and gutters, will over time result in some changes in level evolving. What reasonable approach should be permitted to allow minor, unintended changes in level but also require greater changes to be corrected?
Clear space in crosswalk. I and many other designers are working to reduce the length of crosswalks through the introduction of curb extensions and refuge islands. These can be very beneficial to all pedestrians. What we are trying to do is keep as much of the crosswalk as possible out of the roadway by narrowing the roadway as much as possible.
The clear space within a crosswalk mandated by this section represents unneeded roadway width. This section will prohibit curb extensions. Is that really your intent? I strongly encourage you to revise this section. Please use the regulations to encourage the practice of installing curb extensions at crosswalks, not prevent it.
Width of crosswalks. The requirement that crosswalks have a minimum width of 8’ is another example of introducing a regulation aimed at dense urban environments that would be impractical or counter-productive in other environments. It should be more narrowly drafted.
Crosswalks in outlying areas are lightly used. While a downtown crosswalk may have several hundred persons crossing every hour, even thousands, in suburban areas we usually are talking about less than 100 per day. In this environment, the crosswalk markings are serving a different function, and the potential of conflicting pedestrian movements are very limited and easily overcome.
A major purpose of the crosswalk lines in these less traveled areas is to direct pedestrians in the most advantageous and hopefully shortest route. The crosswalk lines can be very helpful in guiding persons to the curb ramps on opposite side of the street. They can also encourage pedestrians to cross at locations where motorists will have the best sight vision of the pedestrians.
The wide width will restrict the utility of crosswalks in guiding pedestrians to the available curb ramps. In my opinion, an 8’ width may reduce the visibility of the crosswalk compared to a 6’ width, especially if transverse crosswalk lines are used.
In heavily developed urban areas, on the other hand, crosswalk lines may need to be wider than 8’. A procedure should be provided to guide designers in those situations as well.
Cross slope. I recommend that you amend this language to specify that you are speaking of the cross slope of the roadway, not the cross slope of the crosswalk. I was very confused.
Pedestrian signal phase timing. As I understand this section, the draft regulations are requiring that a 14% slower walking speed be assumed. In addition, the regulations require that crosswalks be extended by 48” to provide a clear space within the roadway, and this section requires that the pedestrian clearance interval also include the length of the entire curb ramp, which often are 5 to 10 feet in length.
The net effect of this section will be to create very lengthy pedestrian crossing phases, necessitating longer traffic signal cycles. This in turn will encourage more pedestrians to illegally cross outside of the pedestrian phase, since they will grow impatient.
I agree with the reduction in assumed walking speed. However, agencies should be allowed to retain other current procedures for timing pedestrian phases.
Signals at roundabouts. I strongly oppose this section. Roundabouts have many features that are beneficial to all pedestrians, including those with pedestrians. Most notably, crossing distances are substantially shorter, and motorists have much better ability to see crossing pedestrians compared to turning motorists.
Requiring pedestrian signals at all roundabout crosswalks will substantially increase the cost of installing roundabouts. Since most pedestrians will ignore the signals, finding the short crossing distances easy to negotiate, the use of signals at these locations will breed contempt for traffic signals by pedestrians. If pedestrian signals are activated frequently, traffic engineers will develop lengthy signal cycles, frustrating pedestrians.
Instead, the Board should work with AASHTO and Federal Highway to develop additional design guidance to enhance the visibility of crossing pedestrians and to encourage yielding behavior by motorists. Consideration should be given to using raised crossings or other traffic calming measures to slow drivers at roundabout crosswalks.
If signals are to be required, there should be a volume warrant. As worded, this section would apply to any roundabout regardless of its environment if pedestrian crosswalks and facilities are provided. A neighborhood traffic circle with less than 1000 vehicles ADT would have to have signal controlled crossings even though no signal would be warranted without the circle and the circle would enhance pedestrian safety and slow vehicle speeds.
At exurban locations, this requirement will encourage road designers to eliminate crosswalks and sidewalks so as to avoid the requirement to install pedestrian signals.
I recommend that the Board instead seek to develop a warrant based crosswalk signal that would take into effect the volume of traffic using each roundabout approach and exit, and the volume of pedestrian activity. On roundabouts with high motor vehicle volumes but only limited pedestrian activity, a flasher system should be required to alert motorists to the presence of pedestrians.
Finally, to the extent feasible, if pedestrian signals are to be introduced in areas with roundabouts, it should be done in conjunction with other pedestrian improvements that would move pedestrian crossing locations to mid-block sites independent of the roundabout. From a land use perspective, this is difficult, since it requires directing transportations away from their travel paths.
This is an area requiring much more research.
The proposal as presented is another example of introducing a regulation aimed at a dense urban environment that would be impractical or counter-productive in other environments. It should be more narrowly drafted.
Turn Lanes at Intersections. This section requires the provision of a pedestrian activated traffic signal at any right or left turn slip lane. My comments regarding roundabouts also apply to this recommendation.
The proposal as presented is another example of introducing a regulation aimed at dense urban environments or suburban environments with intense vehicular traffic; it would be impractical or counter-productive in other environments. It should be more narrowly drafted.
Slip lanes are introduced for many reasons. One important one is to accommodate the wide turning requirements of large vehicles with less pavement, especially at intersections with acute angles. This is desirable for all roadway users and can make pedestrian crossings easier to negotiate.
Slip ramps may be appropriate on low volume roadways if the roadways intersect at a very acute angle or if there are large vehicles that use the intersection. In this situation, a traffic signal could not meet any reasonable warrant; a roadway designer would likely prefer to construct a wide, unchannelized intersection rather than install a traffic activated pedestrian signal.
Even in urban locations, most pedestrians will ignore the pedestrian crossing device unless turning volumes are both high and continuous.
Alternative designs for slip ramps are needed that improve a driver’s ability to observe pedestrians and yield to crossing pedestrians. These improved designs exist, and also substantially reduce crashes between motor vehicles. By employing detectable warnings at crossing locations in combination with improved slip ramps, the negative impacts currently experienced can be substantially reduced. Use of rumble strips on slip lanes in advance of crosswalks should be tested as a method of alerting persons with visual disabilities of the presence of an approaching vehicle and would also alert motorists of the crosswalk.
Finally, there is a need to establish a warrant based system to determine when pedestrian activated signals should be installed. I expect that this will usually only be necessary when the volume of turning traffic exceeds 1000 vehicles in the peak design hour.
Location of pedestrian signal devices. I may be misinterpreting this, but I think the last sentence should state that devices should be perpendicular to the direction of the crosswalk it serves. A device parallel to the crosswalk could not be seen. If I am misinterpreting your intent, others also will like do so.
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