This appendix contains material of an advisory nature and provides additional information that should help the reader understand the proposed minimum requirementsof the guidelines or design buildings or facilities for greater accessibility. The paragraph numbers correspond to the sections or paragraphs of the guidelines to which the material relates and therefore are not consecutive (for example A16.1.1 contains additional information relevant to 16.1.1). Sections of the guidelines for which additional material appears in this appendix have been indicated by an asterisk. Nothing in this appendix shall in any way obviate any obligation to comply with the requirements of the guidelines themselves.
A16.1 GENERAL
It is recognized that compliance with the provisions of section 16 may not necessarily result in an accessible facility for all persons with disabilities. The intent is to ensure that accessibility is considered for all newly constructed and altered trails and other outdoor elements, recognizing that natural environments may not always be compatible with fully accessible facilities.
TRAILS
These technical provisions apply only to newly designed and constructed pedestrian trails, and altered portions of existing pedestrian trails that connect to an accessible trail or designated trailhead. Where new trails connect to existing inaccessible trails or do not connect to a designated trailhead, the technical provisions do not apply. However, trails should not be intentionally separated from an accessible trail or designated trailhead with the aim of avoiding the technical provisions. Accessible elements complying with 16.5 through 16.21 located along a trail are not required to be connected by an outdoor recreation access route.
MAINTENANCE AND ALTERATIONS
The following guidance is provided to assist designers and operators distinguish between actions considered "maintenance or repair" and those considered an "alteration." Where actions are considered an "alteration," certain technical provisions from section 16 will apply. Routine or periodic maintenance activities do not trigger the technical and scoping provisions of section 16. For example, if an entirely new bridge were installed to replace a step stone crossing, the bridge would be required to comply with the relevant provisions of Section 16. The trail on either side of the new bridge, however, would not require modification.
As a general rule, alterations are performed to change the original purpose, intent, or design of a facility. Examples of actions that would be considered alterations include, but are not limited to:
Maintenance and repair are performed to return a facility to the standards or conditions to which it was originally designed and built. This type of work is not an alteration because it does not change the original purpose, intent, or design of the facility. It is recognized that in outdoor environments, the ability to maintain the facility is usually much more limited than in the built environment. Except in highly developed areas, maintenance and repair occurs relatively infrequently. Examples of actions that would be considered maintenance and repair includes, but are not limited to:
Although not required, resource managers are encouraged to maximize the opportunity to improve the accessibility of outdoor facilities through maintenance and repair activities. Every time a facility is maintained, the opportunity to improve access is present.
A16.1.1 EXTENT OF APPLICATION
The departures outlined in 16.1.1 are applied technical provision by technical provision and do not provide an overall exemption for the entire trail or outdoor element. When a departure is permitted, a specific exception to the respective technical provision can be applied only on that portion of the trail where the condition for departure exists. For example, a condition for departure allows the width of a trail to be reduced where a significant natural feature is located. However, the width of the trail before and after the significant area must meet the technical provision, and all other technical provisions (except width) will apply throughout the full length of the trail.
A16.1.1.1 Where compliance would cause substantial harm to cultural, historic, religious, or significant natural features or characteristics;
Examples of this condition include areas protected under Federal, State, or local laws, with species designated as threatened or endangered, or with designated wetlands that could be threatened or destroyed by full compliance with the technical provisions. Significant cultural features may include areas such as archaeological sites, sacred lands, burial grounds and cemeteries, Indian tribal protected sites, etc. Significant historical features may include properties on or eligible for the National Register of Historical Places or other places of recognized historic value. Significant religious features may include sites sacred to Native Americans and other properties designated or held sacred by an organized religious belief or church. Significant natural features may include a large rock outcrop or a unique water feature.
A16.1.1.2 Where compliance would substantially alter the nature of the setting or the purpose of the facility, or portion, of the facility;
Examples of this condition include a trail intended to provide a rugged experience such as a cross country training trail with a steep grade or a challenge course with abrupt and severe changes in level, where compliance with certain provisions would not provide the intended and desired level of challenge and difficulty to users. Other examples include trails that traverse over boulders and rocky outcrops where the purpose of the trail is to provide people with the opportunity to climb rocks. To remove the obstacles along the way or reroute the trail around the rocks would destroy the purpose of the trail.
Furthermore, compliance is not intended to negatively impact the unique characteristics of the natural setting. People using primitive trails, for example, expect to experience the outdoor environment in a more natural state with limited or no development. Evidence of manufactured building materials or engineered construction techniques in such a setting could change its primitive character, and therefore, the user's experience. In these settings, compliance with specific technical provisions, for example those related to surface and tread obstacles, could destroy the 'natural' or 'undeveloped' nature of the setting. Actions may also compromise the 'nature of the setting' such as constructing an imported surface on a trail in a remote location or removing ground vegetation in meadows or alpine areas.
A16.1.1.3 Where compliance would require construction methods or materials that are prohibited by Federal, State, or local regulations or statutes;
Restrictions to protect or address environmental concerns imposed by Federal statutes such as the Wilderness Act, Endangered Species Act, and State and local statutes may require departure from one or more of the technical provisions in section 16. For example, Federally designated and some State designated Wilderness Areas prohibit the use of mechanized equipment, limiting construction methods to hand tools. In other areas, imported materials may be prohibited to maintain the integrity of the natural ecosystem. This provision is not intended to automatically exempt organizations restricted under regulations or statutes from the technical provisions specified in Section 16.
Many aquatic features protected under Federal or State laws have limited allowable construction practices. For example, a constructed water crossings required under the technical provisions might not be permitted under certain laws or regulations. Construction methods and materials employed in designated wetlands or coastal areas are also strictly limited.
"Local regulations and statutes" address conditions where "conservation easement" or "development rights" programs prohibit or restrict construction methods and practices. For example, where land is purchased from farms, certain use restrictions may prohibit the importation of surfacing materials. On the other hand, local regulations or statutes may not be developed or initiated with the sole purpose of prohibiting use by people with disabilities. For example, initiating a new local regulation that arbitrarily restricts trail width to a dimension that would not allow passage of wheelchairs or other mobility devices is not permitted under this conditional departure.
A16.1.1.4 Where compliance would not be feasible due to terrain or the prevailing construction practices;
The term "not feasible" is used in this situation to specify what is "reasonably do-able." It does not refer to the technical feasibility with the technical provisions. For example, providing a trail with a 1:20 slope or less up a 1,500 foot tall mountain using heavy construction equipment may be feasible, but the trail would be at least 5.8 miles long (rather than 2 miles long under a traditional back-country layout), and may cause inappropriate environmental and visual impacts. The intent of this conditional departure is to recognize that the effort and resources required to comply would be disproportionately high in relation to the level of access created. Although technically feasible, the effort and resources required are not "reasonable."
For example, complying with the technical provisions, for running slope (16.2.7) in areas of steep terrain may require extensive cuts or fills that would be difficult to construct and maintain, or cause drainage and erosion problems. Also, in order to construct a trail on some steep slopes, the trail may become significantly longer causing a much greater impact on the environment. Certain soils are highly susceptible to erosion. Another example might be in areas where soils expand and dramatically contract with water content. If compliance requires techniques that conflict with the natural drainage or existing soil, the trail would be difficult, if not impossible, to maintain.
This condition may also apply where construction methods for particularly difficult terrain or an obstacle would require the use of equipment other than that otherwise used throughout the length of the trail (i.e., techniques different from prevailing construction practices). One example is requiring the use of a bulldozer to remove a rock outcropping when hand tools are the commonly used method of construction for that trail.
Another example might be where compliance with the provision for a firm and stable surface conflict with the prevailing construction practices by requiring the importation of a new surfacing material that would not otherwise have been used. If the prevailing construction practices would not include the importation of a new surface material and the natural surface material could not be made firm and stable, the trail would not be required to comply with that specific provision.
Trail construction practices vary greatly, from the use of volunteer labor and hand tools, to professional construction with heavy mechanized equipment. For alterations to an existing trail, the "prevailing construction practices" are the methods typically used for construction or maintenance of the trail. The available resources and the environmental conditions (e.g., soil type and depth, vegetation, natural slope) primarily determine the "choice" of construction practices (e.g., machinery, skilled operators, finances). The intent of this conditional departure is to ensure that compliance with the technical provisions does not require the use of construction practices that are beyond the skills and resources of the trail building organization. It is not intended to automatically exempt an organization from the technical provisions simply because of a particular construction practice, (e.g., the use of hand tools) or to suggest that hand tools can be selected as the tool of choice to avoid compliance when more expedient methods and resources are available.
A16.2 TRAILS
Trails include, but are not limited to a trail through a forested park, a shared use path, or a back country trail. Trails covered by 16.2 do not include pathways such as sidewalks, pathways in amusement parks, commercial theme parks, carnivals, or between buildings on college campuses. These exterior accessible routes are covered by ADAAG 4.3.
A trail designed, designated, and constructed for pedestrian use may also have other uses, such as bicycling or in-line skating. Sections 16.2.1 to 16.2.10 apply only to trails where travel on foot is one of the designated uses for which the trail was created. For example, a trail designed specifically for mountain biking would not be considered a "pedestrian trail" whether or not pedestrians actually use the trail. However, a multi-use trail designated for both hiking and mountain biking would be considered a pedestrian trail and subject to these provisions.
Many trails are used as non motorized transportation facilities. Users may include bicyclists and skaters as well as pedestrians. The accessibility guidelines for outdoor developed areas apply to these trails. However, bicyclists and skaters have design needs that may exceed the minimum guidelines for trails in some areas. Where there are differences, the more stringent provision should be applied.
The primary design guide for bicycle and shared use facilities is the Guide for the Development of Bicycle Facilities from the American Association of State Highway and Transportation Officials (AASHTO), 1999. The AASHTO Guide defines "Shared Use Paths" as 'facilities on exclusive rights-of-way and with minimal cross flow by motor vehicles. The term is used in the transportation industry for facilities (often referred to as "bike trails") and built with transportation funds for non-motorized uses, such as bicyclist, skaters, and pedestrian ( In areas with heavy snow, shared used paths may be used by cross-country skiers or snowmobilers.) Shared use paths provide non motorized transportation connections between neighborhoods and communities. They may be along old railroad corridors or rivers, or pass through parks. Shared use paths are usually separated from adjoining roadways or streets either by distance or a barrier, and are usually distinct from sidewalks. They generally have relatively few driveways or street crossings. A summary of how the AASHTO Guide relates to the proposed accessibility guidelines for trails is included below. Trails designed for recreational use by mountain bicyclists are not expected to meet AASHTO Guidelines.
| Outdoor Developed Areas Accessibility Guidelines | AASHTO Guide for the Development of Bicycle Facilities, 1999 |
|---|---|
| 16.2.1 Surface: Firm and stable. |
Bicycles need the same firmness and stability as wheelchairs; skaters usually require a smooth, paved surface. Most shared use paths are paved, although crushed aggregate surfaces are used on some paths. |
| 16.2.2, Clear Tread Width: 36 inches (3 feet; 915 mm); exception for 32 inches (815 mm). |
Shared use paths usually require a minimum 3 meter (10 foot) width,
plus a 0.6 meter (2 foot) safety buffers on both sides. A 2.4 m (8 ft) width may be
allowed in low use facilities. Posts or bollards installed to restrict motor vehicle traffic should be spaced 1.5 m (5 feet) apart. Posts or bollards should be brightly painted and reflectorized for visibility. When more than one post is used, use an odd number, with one on the centerline to help direct opposing traffic. |
| 16.2.3, Surface Openings (Gaps): To prevent wheelchair wheels and cane tips from being caught in surface openings or gaps, openings in trail surfaces shall be of a size which does not permit passage of a ½ inch (13 mm) diameter sphere, elongated openings must be perpendicular or diagonal to the direction of travel; exception to permit parallel direction elongated openings if openings do not permit passage of a ¼ inch (6 mm) sphere; second exception to permit openings which do not permit passage of a ¾ inch (19 mm) sphere. (1) |
The AASHTO Guide does not specify a maximum dimension for a surface opening, but openings should be minimized. Openings should not permit a bicycle wheel to enter. (2) Grates should be flush with the surface, and elongated openings should be perpendicular to the direction of travel. (Diagonal openings are more difficult for bicyclists to negotiate). Where openings are unavoidable, they should be clearly marked. |
| 16.2.4, Protruding
Objects: ADAAG 4.4; provide a warning if vertical clearance is less than 80 inches (2030 mm). |
Protruding objects should not exist within the clear tread width of a shared use path. Vertical clearance on shared use paths should be a minimum of 3 m (10 feet) or the full clear width and the safety buffers. Where vertical barriers and obstructions, such as abutments, piers, and other features are unavoidable, they should be clearly marked. |
| 16.2.5, Tread Obstacles (Changes in level, roots, rocks, ruts): Up to 2 inches (50 mm); exception up to 3 inches (75 mm). |
Tread obstacles are hazardous to bicyclists and skaters. The surface of a shared use path should be smooth and should not have tread obstacles. |
| 16.2.6, Passing Space: At least 60 inches (1525 mm) width within 1,000 foot (300 m) intervals. Appendix note recommends more frequent intervals for some trail segments. |
Shared use paths should have a minimum clear width of 3 m (10 ft), exception for 2.4 m (8 ft). |
| 16.2.7.1 Cross slope:
1:20 (5%) maximum; exceptions for open drains up to 1:10 (10%). |
For drainage, shared use paths should have a minimum 2% (1:50) cross slope on a paved surface. On unpaved shared use paths, particular attention should be paid to drainage to avoid erosion. Curves on shared use paths may require super elevation beyond 2% (1:50) for safety reasons. The Guide suggests limited cross slope for accessibility reasons. |
| 16.2.7.2 Running Slope:
1:20 (5%) any length 1:12 (8.33%) for up to 200 feet 1:10 (10%) for up to 30 feet 1:8 (12.5%) for up to 10 feet No more than 30% of the total trail length shall exceed 1:12 |
Running slopes on shared
use paths should be kept to a minimum; grades greater than 5 percent are undesirable.
Grades steeper than 3 percent may not be practical for shared use paths with crushed stone
or other unpaved surfaces. Where terrain dictates, grade lengths are recommended as
follows: < 5% (< 1:20) any length 5-6% (1:20-16.7) for up to 240 m (800 ft) 7% (1:14.3) for up to 120 m (400 ft) 8% (1:12.5) for up to 90 m (300 ft) 9% (1:11.1) for up to 60 m (200 ft) 10% (1:10) for up to 30 m (100 ft) 11+% (1:9.1) for up to 15 m (50 ft) |
| 16.2.8, Resting Intervals:
Size: 60 inch (1525 mm) length, at least as wide as the widest trail segment adjacent to the rest area. Less than 1:20 (5%) slope in any direction. Resting areas are required where trail running slopes exceed 1:20 (5%), at intervals no greater than the lengths permitted under running slope (see 16.2.7.2 above). |
The Guide does not address resting intervals. |
| 16.2.9, Edge protection:
Where provided, 3 inch (75 mm) minimum height. Handrails are not required. |
The Guide does not address edge protection. Some kinds of edge protection may be hazardous to bicyclists and skaters. The Guide has minimum railing height recommendations when needed for safety reasons. |
| 16.2.10, Signs: Accessible trails require designation with a symbol of accessibility, and information on total length of the accessible segment. No traffic control sign information. |
Guidance on signing and marking is provided in the Manual on Uniform Traffic Control Devices (MUTCD), incorporated by reference as a Federal regulation (23 CFR 655.601). A proposed amendment for Part 9 (Traffic Controls for Bicycle Facilities) was published in the Federal Register on June 24, 1999 (64 FR 33802-33806). A rulemaking is scheduled for March 2000 that will have an update for Part 4 (Signals), that will include provisions for pedestrian signals for people with disabilities. |
The Guide for the Development of Bicycle Facilities is available through the American Association of State Highway and Transportation Officials (AASHTO), 1999, 444 North Capitol St NW, Washington DC 20001, telephone 202-624-5800, fax 202-624-5806, www.aashto.org/bookstore.
A16.2.1 TRAIL SURFACE
Trail surfaces are required to be firm and stable. There are a spectrum of surfaces considered firm and stable and appropriate surfaces are not limited to surfacing materials such as asphalt and concrete. Many naturally occurring surfaces, such as crushed aggregate or soils containing some clay and a spectrum of sieve sizes, are considered firm and stable. Other natural surfaces may also become firm and stable when combined with a stabilizing agent. Wood planks, stone, grass, and packed dirt may also be considered accessible. The degree of firmness and stability may vary depending on the intended use and the expected direction and length of travel.
Preliminary information obtained through a small research project suggests that surfaces considered "firm" (i.e., does not give way significantly under foot) can range from very firm to moderately firm (defined in table A.) Similarly, surfaces considered stable (i.e., do not shift from side-to-side or when turning) can range from very stable to moderately stable.
The degree of firmness and stability desired or most appropriate is related to the intended use of the trail, the predominant direction(s) of travel, and the overall length of the trail. For example, a surface which is both very firm and very stable, is recommended for trails of more than .5 mile in length due to the duration of travel for a person with a disability. However, it may be acceptable for the surface to be moderately firm (rather than very firm) (using calculations and classifications in Table A below) for trails less than .5 but greater than .1 mile in length, and where the travel pattern is primarily linear. It may also be acceptable for the surface to be both moderately firm and moderately stable for trails less than .1 miles in length, and where the trail is moderately level (<3% slope).
Firmness classification
Firm
- Very Firm = 0.3 inch or less penatration
- Moderately Firm = greater than 0.3 and less than 0.5 inch penatration
Not Firm = greater than 0.5 inch penatration
Stability classification
Stable
- Very Stable = 0.5 inch or less penatration
- Moderately Stable = greater than 0.5 and less than 1.0 inch penatration
Not Stable = greater than 1.0 inch penatration
Surfaces that are moderately firm or stable may be appropriate in areas where a cushioned surface is preferred (e.g., for a multi use trail that includes equestrians.) Surfaces that are moderately firm and stable may also be appropriate on trails for winter use only because most trail surfaces are very firm and stable when frozen. Surfaces with a high degree of firmness and stability is critical for long distance trails so users may expend a minimum amount of energy over a given distance. A high degree of stability would be desirable for areas with multi-directional traffic.
Test Method for Firmness and Stability
The following test methodology is based on a preliminary test procedure for the measurement of surface firmness and stability which is one of the ways that firmness and stability can be measured. For more information, consult the "Accessible Exterior Surfaces Technical Report"available through the U. S. Access Board.
Test Equipment
The recommended test equipment for determining firmness and stability on outdoor surfaces is the rotational penetrometer, a device consisting of three main components: penetrator, frame, and reference base. The penetrator consists of an 8 x 1¼ inch(20 cm x 3 cm) pneumatic caster and a means to press the caster into the surface with a known force. The frame is an attachment to the reference base that provides a means for allowing the penetrator to move freely, perpendicular to the reference base. The reference base is a flat, rigid, surface used to position and anchor the testing equipment relative to the test surface. It has an area through which the penetrator can pass and rotate freely without hindering the movement of the surface material being tested or interfering with the test results. The reference base may also provide a platform for the device operator during testing. The rotational penetrometer is instrumented with a method to measure the amount of vertical displacement of the penetrator into the test surface.
Test Procedure
To test surface firmness and stability, the rotational penetrometer is placed on the surface to be tested. A person stands on the reference base of the rotational penetrometer to stabilize its position during testing. The penetrator is lowered onto the test surface and an initial vertical displacement measurement is taken. A load of 44 ± 1 lbs. (20 ± 0.5 kg) is applied to the penetrator and then a second measurement of the amount of vertical displacement is completed. Then, with the load still applied, the penetrator caster is rotated through four 90 degree rotations about an axis perpendicular to the surface, alternating the direction of rotation (clockwise, counter-clockwise) after each 90 degree rotation. The final amount of vertical displacement is then measured. This test procedure is repeated on the same surface in a different test area until a total of five trials have been completed.
A16.2.2 CLEAR TRAIL TREAD WIDTH
The clear tread width of the trail is the width of the useable trail tread. It should be measured perpendicular to the direction of travel and on or parallel to the surface of the useable trail tread. The clear tread width should be measured at intervals no greater than 100 ft (30.5 m).
The minimum clear width of the trail is the width of the usable trail where obstructions restrict the clear tread width and where there is no alternate route to bypass the narrow area. The minimum clear width should be measured at the narrowest point on the trail or trail segment, perpendicular to the direction of travel and on or parallel to the surface of the useable trail tread.
A16.2.5 TRAIL TREAD OBSTACLES
Tread obstacles are natural features, such as roots, rocks, and ruts that cannot be avoided. The trail tread corridor is the area on or above the useable trail tread and below the specified design height for the trail. Tread obstacles in the trail tread corridor should comply with 16.2.5.
The dimensions of the tread obstacle within the trail tread corridor are as follows:
Width - the size of the obstacle within the trail tread corridor, measured perpendicular to the direction of travel;
Length - the size of the obstacle within the trail tread corridor, measured parallel to the direction of travel;
Height - the vertical dimension of the tread obstacle, measured from the trail surface to the top or bottom of the obstacle; and
Remaining clear tread width - the remaining tread corridor that is available to traverse around or past the obstacle, should also be measured perpendicular to the direction of travel.
A16.2.6 TRAIL PASSING SPACE
Passing spaces are required on trails a minimum of every 1000 feet (305 m). However, if a clear tread width less than 60 in (1525 mm) occurs in an area where users cannot easily move off the trail tread, such as a boardwalk or other surface that is not at the same level as the surrounding natural ground surface or where noxious plants are adjacent to the trail tread, passing spaces should be provided at more frequent intervals. The provision of more frequent passing spaces should also be considered in areas with steep or difficult terrain or limited sight lines, so that users do not have to back up long distances to reach a passing space. More frequent passing intervals should also be considered on trails with heavier use, especially closer to trailheads and prominent features. If a bridge less than 60 in (1525 mm) wide is provided, a 60 in x 60 in (1525 mm x 1525 mm) minimum passing space should be provided at either end of the bridge. Passing intervals may be located to one side of the trail and/or co-located with resting intervals.
A16.2.7.1 TRAIL CROSS SLOPE
Trail cross slope is the angle of the trail tread perpendicular to the direction of travel (the side to side slope of the trail). The recommended unit of measurement is percent or rise over run (e.g., 2% or 1:50). Cross slope measurements should be determined across a 24 in (610 mm) width, at intervals not exceeding 100 ft (30.5 m) in length, from the trail head to the destination. Cross slope measurements are taken perpendicular to the path of travel over the most level section of tread at each point.
See A16.2.10 for more information on measuring maximum cross slope.
A16.2.7.2 TRAIL RUNNING SLOPES
The running slope represents the steepness of individual segments of the trail and should be measured parallel to the direction of travel. The recommended unit of measurement is percent or rise over run (e.g., 2% or 1:50). Uphill and downhill trail segments should be measured separately. The distance measured may be as short as 10 ft. (3.1m), but should not exceed 100 ft (30.5m) in length. The running slope should be measured for each consecutive trail segment, from the trail head to the destination.
Uphill trail segments and downhill trail segments should not be located sequentially. A sudden grade change without a transition creates difficulties for wheelchair users.
If there is no transition, there may be insufficient ground clearance. Then the footrests or anti-tip wheels may get caught on the surface.
A sudden grade change without enough of a transition may cause a rapid weight transfer, causing an individual using a wheelchair to lose dynamic stability.
Therefore, uphill and downhill trail segments should be separated by a relatively level transition segment with a slope no greater than 1:20.
See A16.2.10 for information on measuring maximum running slope.
Handrails are not required on trails, even where a maximum running slope occurs. To counterbalance the lack of handrails, the length of steep trail segments permitted is limited and resting intervals are required. Where handrails are provided on a trail, they should comply with ADAAG 4.26.
It is recommended that the use of steps as an alternative route (i.e., in addition to the trail tread surface) be considered for areas where the running slope exceeds 10%, significant changes in elevation are required over a short distance, or significant changes in elevation occur repeatedly along a trail. Providing steps will improve trail conditions for ambulatory people with disabilities, such as those who use crutches or walkers and those with heart or respiratory conditions.
Slope and Rise
Slope represents the proportion of vertical rise to horizontal length and can be represented as a ratio, percentage, pitch or in degrees.
| rise:length | percent | pitch (tangent) | degree |
|---|---|---|---|
| 1:8 | 12.50% | 0.1250 | 7.13 |
| 1:10 | 10 | 0.1000 | 5.71 |
| 1:12 | 8.33 | 0.0833 | 4.76 |
| 1:13 | 7.69 | 0.0769 | 4.40 |
| 1:14 | 7.14 | 0.0714 | 4.09 |
| 1:15 | 6.67 | 0.0667 | 3.81 |
| 1:16 | 6.25 | 0.0625 | 3.58 |
| 1:17 | 5.88 | 0.0588 | 3.37 |
| 1:18 | 5.55 | 0.0555 | 3.18 |
| 1:19 | 5.26 | 0.0526 | 3.01 |
| 1:20 | 5.00 | 0.0500 | 2.86 |
| 1:50 | 2.00 | 0.0200 | 1.15 |
A16.2.8 TRAIL RESTING INTERVALS
Resting intervals should be provided between uphill and downhill trail segments if the running slope for either segment exceeds 1:12, as well as at intervals on a continuous slope as specified by 16.2.7.2. Rest intervals should be positioned so that a smooth, gradual transition is provided between running slope segments. Rest intervals may be located within the trail tread. However, locating the rest interval outside of the main path of travel will ensure that users who are resting are not at risk of collisions with other trail users.
More frequent resting intervals should be considered on trails with heavier use, and especially close to trailheads and prominent features. Resting intervals may be located to one side of the trail, and/or co-located with passing intervals.
A16.2.9 TRAIL EDGE PROTECTION
If edge protection is provided, a 3 in (75 mm) minimum height is required. The higher edge protection is required because trail surfaces are likely to have natural variations in the height of the surface. As a result, people with limited vision using navigation canes may search or scan at a higher level in natural outdoor environments than they would in an indoor environment. The higher edge protection will assist in its detection and identification and help to distinguish it from variations in the natural surface of the outdoor environment.
Regardless of the orientation or design of the edge protection, the height of edge protection provided on the trail should be measured in the vertical dimension to the highest point on the edge protection. Where edge protection is provided, small openings may be placed at the base of the edge protection close to the trail surface to allow water to drain off the trail. Care should be taken to clear debris that may build up along the edge protection.
A16.2.10 TRAIL SIGNS
Trails complying with the technical provisions and exceptions of 16 must be identified by an access symbol. While the committee did not decide on a particular sign, possible designs for considerations follow.
Given the wide variability in the actual trail characteristics that may be encountered on a trail, it is strongly recommended that objective information about the actual trail conditions be provided for all trails, whether or not they are accessible. Objective information about actual trail condition for all trails will assist users in determining whether the trail meets their own abilities. The provision of objective information regarding the accessibility of the actual trail conditions is strongly recommended for all trails or trail segments that do not fully comply with the ADAAG Technical Specifications for Recreational Trails. The variability of conditions on these trails can be very dramatic, and may range from relatively minor variations from the technical standards to extreme conditions. Objective information about the trail conditions will enhance the accessibility, safety, and satisfaction of all trail users, both with and without disabilities.
It is further recommended that where more extensive trail information is provided (e.g., a top view map of trail and facilities), that the location of specific trail features and obstacles that do not comply with accessibility provisions be identified and that a profile of the trail grade and surface be included.
Where more extensive trail information is provided (e.g., a top view map of trail and facilities), a profile of the trail grade and surface should be included, identifying any parts of the trail that are not accessible, along with the location of the accessible trail segments.
Recommendations for measurement techniques for the individual trail variables are included at the end of this section.
Recommended Information to be Provided for Recreational Trails
For trails that comply with the ADAAG specifications for recreational trails it is recommended that the following additional information be provided:
For trails that do not comply with the ADAAG Technical Provisions for Recreational Trails, it is recommended that the following information be provided:
Recommended Measurement Techniques for Trail Information Variables
The following definitions describe how measurements should be made in order to provide the recommended information for trail sign age:
The type of material that makes up the majority of the surface should be described (e.g., packed soil, asphalt, crushed rock, wood). The firmness of the surface should be described as "very firm" or "moderately firm". The stability of the surface should be described as "very stable" or "moderately stable". (See Table A in Section A16.2.1 for information on measuring firmness and stability.)
Average clear tread width represents the typical clear tread width over the entire length of the trail. Average clear tread width should be determined by averaging the individual clear trail widths for each sequential segment of the trail from the trail head to the destination. (See Section A16.2.2 for additional information on measuring clear tread width).
See Section A16.2.4 for information on measuring tread obstacles.
Average running slope represents the typical steepness of the entire length of the trail. The running slope should be measured for each sequential trail segment, from the trail head to the destination. It is recommended that trail segments be identified in 100 ft (30.5 m) maximum lengths. Calculation of the average running slope should be based on the running slope for each trail segment taking into consideration the interval over which each measurement was made.
Maximum running slope represents the section(s) of the trail with the steepest grade. Maximum running slope should be determined over the best (i.e., most level) path of travel for that segment of the trail. For example, a 10 feet wide trail may have a steep rut on one edge of the trail because that side of the trail has eroded significantly. The rut is 3 feet wide and continues along the trail for 50 feet. The running slope when you walk down into the rut is 20%.. The remaining 7 feet on the right-hand side of the trail has a running slope of 10%. The maximum running slope would be measured as 10% .
Average cross slope represents the angle of the tread over the entire length of the trail. The average cross slope should be determined by taking the average of the cross slope measurements taken at intervals of 100 ft (30.5 m) or less from the trailhead to the destination, along the easiest or most level path of travel along the trail. Trail cross slope should be measured over a 24 in (610 mm) width. Calculation of the average cross slope is the average value of all cross slope measurements taking into consideration the length of the interval between each measurement.
Maximum cross slope should be determined over the best (i.e., most level) path of travel for that segment of the trail. For example, a 6 foot wide trail may have a steep side slope on one edge of the trail. This section has an 8% cross slope that extends 2 feet from the edge of the trail tread. The remaining 4 feet on the other side of the trail has a cross slope of 3%. The maximum cross slope would be measured as 3%.
The distance from the trailhead to the destination or end of trail should be measured in linear feet along the center line of the trail.
The elevation should be recorded at the trail head, at the highest point on the trail and at the lowest point on the trail. Total elevation change is the sum of all elevation gains and losses, indicating the total amount of elevation which must be negotiated. The following are examples of generic sign age formats that include the access information recommended in Section A16.2.11.
A16.3 OUTDOOR RECREATION ACCESS ROUTE
Accessible elements complying with 16.5 through 16.21 located along a trail are not required to be connected by an outdoor recreation access route.
A16.3.1 OUTDOOR RECREATION ACCESS ROUTE SURFACE
The degree of firmness and stability desired or most appropriate is related to the intended use of the outdoor recreation access route, the predominant direction(s) of travel and the overall length of the outdoor recreation access route. For example, a surface which is both very firm and very stable, is recommended for outdoor recreation access routes of more than .5 mile in length due to the duration of travel for a person with a disability. However, it may be acceptable for the surface to be moderately firm (rather than very firm) (using calculations and classifications in Section 16.2.1, Table A) in 16.2.1 for outdoor recreation access routes less than .5 but greater than .1 mile in length, and where the travel pattern is primarily linear. It may also be acceptable for the surface to be both moderately firm and moderately stable for outdoor recreation access routes less than .1 miles in length, and where the outdoor recreation access route is moderately level (<3% slope).
Test Methods for Surface Firmness and Stability - See section A16.2.1 for test methods related to firmness and stability.
A16.3.5 OUTDOOR RECREATION ACCESS ROUTE TREAD OBSTACLES
Beveling is only recommended where prevailing construction practices permit the use of hardened surfaces. Beveling with dirt or other natural surfaces is generally not effective because the beveled surface will quickly erode. For example, if you do not bevel a root or rock with concrete or a similar imported surface, the dirt will quickly erode and the benefit of the beveling will be lost. Tread obstacles should be avoided as much as possible, because they may pose a tripping hazard.
A16.3.6 OUTDOOR RECREATION ACCESS ROUTE PASSING SPACE
An outdoor recreation access route less than 60 inches(150 cm) wide may need more frequent passing intervals depending on use, or if the surface is constructed on a boardwalk or other surface that are is at the same level as the surrounding ground surface. More frequent passing intervals may be needed on heavily used outdoor recreation access routes, especially close to higher use elements. Passing intervals may be located to one side of the trail, and/or co-located with resting intervals.
A16.3.7.1 OUTDOOR RECREATION ACCESS ROUTE CROSS SLOPE
Cross slope on an outdoor recreation access route is defined as the angle of the route tread perpendicular to the direction of travel (the side-to-side slope of the route). The recommended unit of measurement is percent or rise over run (e.g., 2% or 1:50). Cross slope measurements should be determined across the most level 24 in (610 mm) width of the trail. Cross slope measurements should be taken perpendicular to the path of travel at intervals not exceeding 100 feet (30.5 m) in length.
Maximum cross slopes for outdoor recreation access routes represent the section(s) of the route with the greatest angle of the route tread. Maximum cross slopes should be determined over the most level path of travel along the route. (See A16.2.10 for more information on measuring cross slope.)
A16.3.7.2 OUTDOOR RECREATION ACCESS ROUTE RUNNING SLOPE
The running slope of an outdoor recreation access route represents the steepness of individual segments of the route and should be measured parallel to the direction of travel. The recommended unit of measurement is percent or rise over run (e.g., 2% or 1:50). The distance measured should not exceed 100 ft (30.5 m) in length. The running slope should be measured for each sequential route segment.
Maximum running slope of an outdoor recreation access route represents the steepest section(s) of the route. The maximum running slope is measured over a 24 in (610 mm) distance parallel to the path of travel. (See 16.2.10 for more information on measuring running slope.)
Outdoor recreation access routes are not required to have handrails, even where a maximum running slope occurs. To counterbalance the lack of handrails, the provision for running slope limits the length of steep segments and requires resting intervals. Where handrails are provided, they should comply with 4.26.
Uphill trail segments and downhill trail segments should not be located sequentially. A sudden grade change without a transition creates d difficulties for wheelchair users.
Therefore, uphill and downhill trail segments should be separated by a relatively level transition segment with a slope no greater than 1:20.
A16.3.8 OUTDOOR RECREATION ACCESS ROUTE RESTING INTERVALS
More frequent resting intervals may be needed on heavily used outdoor recreation access routes, especially close to higher use elements. Resting intervals should be located to one side of the outdoor recreation access route, and/or co-located with passing intervals.
A16.3.9 EDGE PROTECTION
Where edge protection is provided, small openings may be placed at the base of the edge protection close to the trail surface to allow water to drain off the surface. Care should be taken to clear debris that may build up along the edge protection.
A16.4.2 BEACH ACCESS ROUTE SURFACE
The degree of firmness and stability desired or most appropriate is related to the intended use of the trail, the predominant direction(s) of travel, and the overall length of the beach access route. For example, a surface which is both very firm and very stable,(using calculations and classifications in Table A in Section 16.2.1) is recommended for beach access routes of more than .5 mile in length due to the duration of travel for a person with a disability. However, it may be acceptable for the surface to be moderately firm (rather than very firm) for beach access routes less than .5 but greater than .1 mile in length, and where the travel pattern is primarily linear. It may also be acceptable for the surface to be both moderately firm and moderately stable for beach access routes less than .1 miles in length, and where the beach access route is moderately level (<3% slope).
See section A16.2.1 for test methods related to firmness and stability.
A16.5 PICNIC TABLES
This provision applies only to picnic tables that are "fixed" to the ground and includes picnic tables attached to the ground by a chain from the table to a concrete footing below ground.
A16.5.1.2 MULTIPLE PICNIC TABLES
Where two or more fixed picnic tables are provided in a picnic area, at least 50 percent, but never less than two, must comply with 16.5.4 through 16.5.6. An "area" refers to a designated location where picnic related elements are located. Areas may be separated and include different settings on the same site. For example, a picnic area located next to a lake in a park is considered a separate picnic area from a pavilion with numerous picnic tables within the same park. Picnic "areas" may also be separated and designated by a name or connected to a separate entrance.
A16.5.4. WHEELCHAIR SEATING SPACE SIZE
The location of the space has not been specified in this provision. Where multiple tables are provided, it is recommended that a variety of space placements be included to provide users with a choice such as locating the space in the center of the seating area of the table or at the ends of the tables.
A16.5.9 PICNIC ELEMENTS SURFACE, A16.6.7 FIRE RINGS SURFACE, A16.7.8 COOKING SURFACES, GRILLS, PEDESTAL GRILLS SURFACE, A16.8.3 FIXED TRASH/RECYCLING CONTAINERS SURFACE, A16.9.5 WOOD STOVES AND FIREPLACES SURFACE, A16.10.4 OVERLOOK/VIEWING AREA SURFACE, A16.11.9 TELESCOPES AND PERISCOPES SURFACE, A16.12.9 BENCH SURFACE, A16.14.4 MOBILITY DEVICE STORAGE SURFACE, A16.15.6 PIT TOILETS SURFACE, A16.16.5 UTILITY SURFACE, A16.17.3.2 TENT PAD SURFACE, A16.17.11.3 CAMPING ELEMENTS TENT PLATFORM SURFACE
Ground surfaces in outdoor areas that are level (less than 3% slope in any direction to allow drainage) and where the distances traveled are less than 50 ft (e.g., around a picnic table) should be at least moderately firm and moderately stable.(See Table A in Section 16.2.1.and for more information related to test methods for surface firmness and stability)
A16.8 TRASH AND RECYCLING CONTAINERS
The U.S.D.A. Forest Service Technology and Training Center (San Dimas, CA) has issued a document which provides information about animal resistant garbage containers. Suggested designs may be useful in complying with these provisions ; #9523 1205 SDTDC 444 East Bonita Ave. San Dimas, CA 91773
A16.10 OVERLOOK/VIEWING AREAS
Overlooks and viewing areas are specifically designed and constructed to provide an observation of a vista or to a specific point of interest, such as the view to a mountain range or down into a valley or to a waterfall or geologic formation.
Each location that provides a viewing opportunity to one or more distinct points(s) of interest must have at least one unrestricted viewing area for each viewing opportunity. Safety barriers, guardrails, and walls used to protect the visitor from an edge or drop off, may not restrict this viewing opportunity. Designs including see-through panels in walls, screened openings or elevated platforms away from the guarded edge will provide the individual seated in a wheelchair or other mobility devices with the same view.
A16.11 TELESCOPES AND PERISCOPES
Telescopes and periscopes need to be designed for people of various heights, including children, people seated and those standing. Several options are available at locations where there is only one telescope or periscope, such as providing an adjustable scope, an adjustable seat, or a single base with two viewing scopes located at different heights. Use of swing away seat, small step or ring platform attached to the mounting post of the instrument would be useful for persons of short stature or children.
A16.19 RINSE SHOWERS
Outdoor showers are usually rinsing facilities that permit people to wash off sand, water, dirt, debris, etc. They are not designed for bathing, as they generally do not offer privacy and people are usually not permitted to disrobe.
1. The exception to allow a 3/4 inch(19mm) opening is the maximum when accounting for expansion and contraction under various outdoor weather conditions. A 3/4 inch (19mm) opening may cause problems for wheelchair users who wish to turn and for cane users.
2. Openings should be of a size which does not permit cane tips, wheelchair wheels, or skate wheels to get caught.