Chapter T3: Technical Provisions

T301  General

T301.1  Scope.  The provisions of Chapter T3 shall apply where required by Chapter T2 or where referenced by a requirement in this document.

T302  Conditions for Exceptions

T302.1 General.  Where any of the conditions in T302 applies, the specific exceptions to the technical provisions in Chapter T3 shall be permitted.  The conditions in T302 do not obviate or limit in any way the obligation to comply with the technical provisions in Chapter T3 at any point where the conditions do not apply.

Advisory T302.1 Conditions for Exceptions.  The conditions in T302 permit specific exceptions technical provision by technical provision and do not provide an overall exemption for the entire trail or outdoor element.  A specific exception to a technical provision can be used only on that portion of the trail where the condition exists.  For example, an exception to T303.4 permits 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 T303.4, and all other technical provisions (except width where the significant natural feature is located) will apply throughout the full length of the trail.

Conditions 1.  Compliance would cause substantial harm to cultural, historic, religious, or significant natural features or characteristics.

Advisory T302.1 Condition 1.  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, or Indian tribal protected sites.  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.

2.  Compliance would substantially alter the nature of the setting or the purpose of the facility, or portion of the facility.

Advisory T302.1 Condition 2.  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 technical 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.

3.  Compliance would require construction methods or materials that are prohibited by federal, state, or local regulations or statutes.

Advisory T302.1 Condition 3.  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 permit exceptions to the technical provisions in Chapter T3.  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 condition is not intended to automatically exempt organizations restricted under regulations or statutes from the technical provisions in Chapter T3.

Many aquatic features protected under Federal or State laws have limited allowable construction practices.  For example, a constructed water crossing 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 condition.

4.  Compliance would not be feasible due to terrain or the prevailing construction practices.

Advisory T302.1 Condition 4.  Compliance would not be feasible due to terrain or the prevailing construction practices.  The term “not feasible” is used in this condition to specify what is “reasonably do-able.” It does not refer to the technical feasibility of complying 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 condition 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 (T303.8.2) 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 (T303.3) conflicts 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 condition 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.

T303  Trails

T303.1  General.  Trails shall comply with T303.

T303.2  General Exception.  Where applying the specific exceptions to the technical provisions in T303 results in any of the conditions in T303.2, the trail shall not be required to comply with T303 beyond the first point where the specific exceptions apply. The segment of the trail between the trailhead and the first point where the specific exceptions apply shall comply with T303 unless the trail segment is 500 feet (150 m) or less in length.  Where there is a prominent feature less than 500 feet (150 m) from the trailhead, the trail segment between the trailhead and the prominent feature shall comply with T303.

Conditions 1.  The combination of running slope and cross slope exceeds 40 percent for over 20 feet (6100 mm).

2.  A trail obstacle 30 inches (760 mm) high or more runs across the full tread width of the trail.

3.  The trail surface is neither firm nor stable for a distance of 45 feet (14 m) or more.

4.  The tread width is less than 12 inches (305 mm) wide for a distance of 20 feet (6100 mm) or more.

5.  The trail is not required to comply with any of the technical provisions in T303 for more than 15 percent of the length of the trail.

T303.3  Surface.  The trail surface shall be firm and stable.

EXCEPTION:  Where a firm and stable surface cannot be provided because any of the conditions in T302 applies, the surface shall not be required to comply with T303.3.

Advisory T303.3  Surface.  Trail surfaces are required to be firm and stable.  There is 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 firm and stable.  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 on accessible exterior surfaces conducted for the Access Board 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 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 mile 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 mile in length, and where the trail is moderately level (< 3% slope).

Table A Calculation and Classification
Firmness ClassificationAmount of Penetration
Very Firm 0.3 inches or less
Firm Greater than 0.3 inches and less than 0.5 inches
Not Firm Greater than 0.5 inches
Stability Classification Amount of Penetration
Very Stable 0.5 inches or less
Moderately Stable Greater than 0.5 inches and less than 1.0 inch
Not Stable Greater than 1.0 inch

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 are 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.

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 Access Board.  (www.access-board.gov)

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 by 1  inch (20 cm by 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.

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 pound (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.

T303.4  Clear Tread Width.  The clear tread width of trails shall be 36 inches (915 mm) minimum.

EXCEPTIONS:  1.  Where 36 inches (915 mm) minimum clear tread width cannot be provided because any of the conditions in T302 applies, the clear tread width shall be permitted to be reduced to no less than 32 inches (815 mm) minimum.

2.  Where 32 inches (815 mm) minimum clear tread width cannot be provided because any of the conditions in T302 applies, the clear tread width shall not be required to comply with T303.4.

Advisory T303.4  Clear Tread Width.  The clear tread width of the trail is the width of the usable trail tread.  It should be measured perpendicular to the direction of travel and on or parallel to the surface of the usable trail tread.  The clear tread width should be measured at intervals no greater than 100 feet (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 usable trail tread.

T303.5  Openings.  Openings in trail surfaces shall be of a size that does not permit passage of a 1/2 inch (13 mm) diameter sphere.  Elongated openings shall be placed so that the long dimension is perpendicular or diagonal to the dominant direction of travel.

EXCEPTIONS:  1.  Elongated openings shall be permitted to be parallel to the dominant direction of travel provided the opening does not permit passage of a 1/4 inch (6.5 mm) diameter sphere.

2.  Where openings that do not permit passage of a 1/2 inch (13 mm) diameter sphere cannot be provided because any of the conditions in T302 applies, openings shall be permitted to be of a size that does not permit passage of a 3/4 inch (19 mm) diameter sphere.

3.  Where openings that do not permit passage of a inch 3/4 (19 mm) diameter sphere cannot be provided because any of the conditions in T302 applies, the openings in trail surfaces shall not be required to comply with T303.5.

T303.6  Tread Obstacles.  Where tread obstacles exist on trails, the obstacles shall not exceed 2 inches (50 mm) high maximum.

EXCEPTIONS:  1.  Where running and cross slopes are 1:20 or less, tread obstacles shall be permitted to be 3 inches (75 mm) high maximum.

2.  Where tread obstacles greater than 3 inches (75 mm) high exist because any of the conditions in T302 applies, the tread obstacles shall not be required to comply with T303.6.

Advisory T303.6  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 usable trail tread and below the specified design height for the trail.  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.

T303.7  Passing Space.  Where the clear tread width of trails is less than 60 inches (1525 mm), passing spaces shall be provided at intervals of 1000 feet (300 m) maximum.  Passing spaces shall be either a 60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum space, or an intersection of two walking surfaces which provide a T-shaped space complying with T402.1.2 provided the arms and stem of the T-shaped space extend at least 48 inches (1220 mm) beyond the intersection.

EXCEPTION:  Where passing spaces cannot be provided because any of the conditions in T302 applies, passing spaces shall not be required.

Advisory T303.7  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 inches (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 spaces should also be considered on trails with heavier use, especially closer to trailheads and prominent features.  If a bridge less than 60 inches (1525 mm) wide is provided, a 60 inches by 60 inches (1525 mm by 1525 mm) minimum passing space should be provided at either end of the bridge.  Passing spaces may be located to one side of the trail and co-located with resting intervals.

T303.8  Slopes.  Slopes shall comply with T303.8.1 and T303.8.2.

EXCEPTIONS:  1.  For open drainage structures, a running slope of 1:7 shall be permitted for 5 feet maximum (1525 mm) with a cross slope of 1:20 maximum.  Cross slope shall be permitted to be 1:10 at the bottom of the open drain provided the clear tread width is 42 inches (1065 mm) minimum.

2.  Where slopes cannot comply with T303.8 because any of the conditions in T302 applies, the requirements of T303.8 shall not apply.

T303.8.1  Cross Slope.  The cross slope shall not exceed 1:20 maximum.

Advisory T303.8.1  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.  Additional information on measuring maximum trail cross slope is provided in Advisory T222.1 Trail Signs.

T303.8.2  Running Slope.  The running slope shall comply with one or more of the provisions in T303.8.2.  No more than 30 percent of the total trail length shall exceed a running slope of 1:12.

T303.8.2.1  Running slope shall be 1:20 or less for any distance.

T303.8.2.2  Running slope shall be 1:12 maximum for 200 feet (61 m) maximum.  Resting intervals complying with T303.9 shall be provided at distances no greater than 200 feet (61 m) apart.

T303.8.2.3  Running slope shall be 1:10 maximum for 30 feet (9150 mm) maximum.  Resting intervals complying with T303.9 shall be provided at distances no greater than 30 feet (9150 mm) apart.

T303.8.2.4  Running slope shall be 1:8 maximum for 10 feet (3050 mm) maximum.  Resting intervals complying with T303.9 shall be provided at distances no greater than 10 feet (3050 mm) apart.

Advisory T303.8.2  Running Slope.  The running slope represents the steepness of individual segments of a 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 feet (3.1m), but should not exceed 100 feet (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.

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 the ABA Accessibility Guidelines.

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 percent, 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 represents the proportion of vertical rise to horizontal length and can be represented as a ratio, percentage, pitch or in degrees.

Rise:LengthPercentPitchDegree
1:8 12.50 0.1250 7.13
1:10 10.00 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

T303.9  Resting Intervals.  Resting intervals shall be 60 inches (1525 mm) long minimum, shall be at least as wide as the widest portion of the trail segment leading to the resting interval, and shall have a slope not exceeding 1:20 in all directions.

EXCEPTION:  Where resting intervals cannot be provided because any of the conditions in T302 applies, resting intervals shall not be required.

Advisory T303.9  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 T303.8.2.  Resting intervals should be positioned so that a smooth, gradual transition is provided between running slope segments.  Resting intervals may be located within the trail tread.  However, locating the resting 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, or co-located with passing spaces.

T303.10  Edge Protection.  Where edge protection is provided, the edge protection shall be 3 inches (75 mm) high minimum.

Advisory T303.10  Edge Protection.  If edge protection is provided, a 3 inch (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 a 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.

T304  Outdoor Recreation Access Routes

T304.1  General.  Outdoor recreation access routes shall comply with T304.

T304.2  Surface.  The surface of outdoor recreation access routes shall be firm and stable.

Advisory T304.2  Surface.  The degree of firmness and stability desired or most appropriate is related to the intended use of an outdoor recreation access route, the predominant direction 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 the advisory for T303.3, Table A) 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).  See advisory for T303.3 for test methods related to firmness and stability.

T304.3  Clear Tread Width.  The clear tread width of outdoor recreation access routes shall be 36 inches (915 mm) minimum.

EXCEPTION:  Where 36 inches (815 mm) minimum clear tread width cannot be provided because any of the conditions in T302 applies, the clear tread width shall be permitted to be reduced to no less than 32 inches (815 mm) minimum for a distance of 24 inches (610 mm) maximum.

T304.4  Openings.  Openings in the surfaces of outdoor recreation access routes shall be of a size that does not permit passage of a 1/2 inch (13 mm) diameter sphere.  Elongated openings shall be placed so that the long dimension is perpendicular or diagonal to the dominant direction of travel.

EXCEPTION:  Elongated openings shall be permitted to be parallel to the dominant direction of travel provided the opening does not permit passage of a 1/4 inch (6.5 mm) diameter sphere.

T304.5  Tread Obstacles.  Where tread obstacles exist on outdoor recreation access routes, the obstacles shall not exceed 1 inch (25 mm) high maximum.

EXCEPTION:  Where tread obstacles greater than 1 inch (25 mm) high exist because any of the conditions in T302 applies, tread obstacles shall be permitted to be 2 inches (50 mm) high maximum provided they are beveled with a slope no greater than 1:2.

Advisory T304.5  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 a root or rock is not beveled 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.

T304.6  Passing Space.  Where the clear tread width of outdoor recreation access routes is less than 60 inches (1525 mm), passing spaces shall be provided at intervals of 200 feet (61 m) maximum.  Passing spaces shall be either a 60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum space, or an intersection of two walking surfaces which provide a T-shaped space complying with T402.1.2 provided the arms and stem of the T-shaped space extend at least 48 inches (1220 mm) beyond the intersection.

EXCEPTION:  Where passing spaces cannot be provided at intervals of 200 feet (61 m) maximum because any of the conditions in T302 applies, passing spaces shall be permitted at intervals of 300 feet (91 m) maximum.

Advisory T304.6  Passing Space.  An outdoor recreation access route less than 60 inches (1525 mm) wide may need more frequent passing spaces depending on use, or if the surface is constructed on a boardwalk or other surface that is at the same level as the surrounding ground surface.  More frequent passing spaces may be needed on heavily used outdoor recreation access routes, especially close to higher use elements. Passing spaces may be located to one side of the trail, or co-located with resting intervals.

T304.7  Slopes.  Slopes shall comply with T304.7.1 and T304.7.2.

T304.7.1  Cross Slope.  The cross slope shall not exceed 1:33 maximum.

EXCEPTION:  Where required for proper drainage, cross slopes not exceeding 1:20 maximum shall be permitted.

Advisory T304.7.1  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 inch (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 sections 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.

T304.7.2  Running Slope.  The running slope shall comply with one or more of the provisions of T304.7.2.

T304.7.2.1  Running slope shall be 1:20 or less for any distance.

T304.7.2.2  Running slope shall be 1:12 maximum for 50 feet (15 m) maximum.  Resting intervals complying with T304.8 shall be provided at distances no greater than 50 feet (15 m) apart.

T304.7.2.3  Running slope shall be 1:10 maximum for 30 feet (9150 mm) maximum.  Resting intervals complying with T304.8 shall be provided at distances no greater than 30 feet (9 m) apart.

Advisory T304.7.2  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 feet (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 sections of the route.  The maximum running slope is measured over a 24 inch (610 mm) distance parallel to the path of travel.

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 the revised ABA Accessibility Guidelines.  Uphill segments and downhill 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 and 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 segments should be separated by a relatively level transition segment with a slope no greater than 1:20.

T304.8  Resting Intervals.  Resting intervals shall be 60 inches (1525 mm) long minimum, shall be at least as wide as the widest portion of the segment leading to the resting interval, and have a slope not exceeding 1:33 in all directions.

EXCEPTION:  Where required for proper drainage, cross slopes not exceeding 1:20 maximum shall be permitted.

Advisory T304.8  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, or co-located with passing spaces.

T304.9  Edge Protection.  Where edge protection is provided, the edge protection shall be 3 inches (75 mm) high minimum.

Advisory T304.9  Edge Protection.  Where edge protection is provided, small openings may be placed at the base of the edge protection close to the surface of the outdoor recreation access route to allow water to drain off the surface.  Care should be taken to clear debris that may build up along the edge protection.
T305  Beach Access Routes

T305.1  General.  Beach access routes shall comply with T305.

T305.2  Surface.  The surface of beach access routes shall be firm and stable.

Advisory T305.2  Surface.  The degree of firmness and stability desired or most appropriate is related to the intended use of the beach access route, the predominant direction 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 the advisory for T303.3) 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 mile in length, and where the beach access route is moderately level (<3% slope).  See advisory for T303.3 for test methods related to firmness and stability.

T305.3  Location.  The beach access route shall extend to the high tide level, mean river bed level, or the normal recreation water level.

T305.4  Clear Width.  The clear width of beach access routes shall be 36 inches (915 mm) minimum.

T305.5  Openings.  Openings in the surfaces of beach access routes shall be of a size that does not permit passage of a 1/2 inch (13 mm) diameter sphere.  Elongated openings shall be placed so that the long dimension is perpendicular or diagonal to the dominant direction of travel.

EXCEPTION:  Elongated openings shall be permitted to be parallel to the dominate direction of travel provided the opening does not permit passage of 1/4 inch (6.5 mm) sphere.

T305.6  Obstacles.  Obstacles on beach access routes shall not exceed 1 inch (25 mm) high maximum.

T305.7  Passing Space.  Where the clear width of beach access routes is less than 60 inches (1525 mm), passing spaces shall be provided at intervals of 200 feet (61 m) maximum.  Passing spaces shall be either a 60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum space, or an intersection of two walking surfaces which provide a T-shaped space complying with T402.1.2 provided the arms and stem of the T-shaped space extend at least 48 inches (1220 mm) beyond the intersection.

T305.8  Turning Space.  Turning space shall be provided at the high tide level, mean river bed level, normal recreation water level, or end of the beach access route.  Turning space shall not overlap with the beach access route and shall be either a 60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum space, or an intersection of two walking surfaces which provides a T-shaped space complying with T402.1.2 provided that the arms and stem of the T-shaped space extend at least 48 inches (1220 mm) beyond the intersection.

T305.9  Slopes.  Slopes shall comply with T305.9.1 and T305.9.2.

T305.9.1  Cross Slope.  The cross slope shall not exceed 1:33 maximum.

EXCEPTION:  Where required for proper drainage, cross slopes not exceeding 1:20 maximum shall be permitted.

T305.9.2  Running Slope.  The running slope shall comply with one or more of the provisions in T305.9.2.

T305.9.2.1  Running slope shall be 1:20 or less for any distance.

T305.9.2.2  Running slope shall be 1:12 maximum for 50 feet (15 m) maximum.  Resting intervals complying with T304.8 shall be provided at distances no greater than 50 feet (15 m) apart.

T305.9.2.3  Running slope shall be 1:10 maximum for 30 feet (9 m) maximum.  Resting intervals complying with T304.8 shall be provided at distances no greater than 30 feet (9 m) apart.

T305.10  Edge Protection.  If the drop-off from the beach access route to the beach is 6 inches (150 mm) or higher, the beach access route shall have curbs, walls, railings, or projecting surfaces that prevent people from falling off the route.  Edge protection shall be 2 inches (50 mm) high minimum.  If the drop-off is greater than 1 inch (25 mm), but less than 6 inches (150 mm), then the edge must be beveled.

T306  Picnic Tables

T306.1  General.  Picnic tables shall comply with T306.

Advisory T306.1  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.

T306.2  Wheelchair Spaces.  Wheelchair spaces shall comply with T306.4 and T403. Wheelchair spaces shall provide knee space at least 27 inches (685 mm) high, 30 inches (760 mm) wide, and 19 inches (485 mm) deep.  Toe clearance 9 inches (230 mm) high minimum shall extend an additional 5 inches (127 mm) minimum from the knee clearance.

Advisory T306.2  Wheelchair Spaces.  The location of the wheelchair 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.

T306.3  Table Clearance.  A 36 inches (915 mm) minimum clear space complying with T306.4 shall be provided around the usable portion of the table, measured from the back edge of the seat.

T306.4  Clear Spaces.  Clear spaces shall comply with T306.4.

T306.4.1  Surface.  The surface of clear spaces shall be firm and stable.

EXCEPTION:  Where a firm and stable surface cannot be provided because any of the conditions in T302 applies, the surface of the clear space shall not be required to comply with T306.4.1.

T306.4.2  Slope.  The slope of clear spaces shall not exceed 1:50 in all directions.

EXCEPTIONS:  1.  Where required for proper drainage, slopes not exceeding 1:33 maximum shall be permitted.

2.  Where slopes not exceeding 1:33 maximum cannot be provided because any of the conditions in T302 applies, the slope of the clear space shall not be required to comply with T306.4.2.

Advisory T306.4  Clear Spaces.  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 feet (e.g., around a picnic table) should be at least moderately firm and moderately stable (see Table A in section T303.3 and for more information related to test methods for surface firmness and stability).
T307  Fire Rings

T307.1  General.  Fire rings shall comply with T307.

T307.2  Clear Space.  All usable portions of the fire ring shall be provided with a clear space complying with T306.4 that is 48 inches (1220 mm) deep minimum measured from the fire ring and 48 inches (1220 mm) wide minimum.

EXCEPTION:  Where a clear space 48 inches (1220 mm) deep minimum cannot be provided because any of the conditions in T302 applies, the space shall be permitted to be reduced by the minimum necessary but shall not be less than 36 inches (815 mm) deep minimum.

T307.3  Fire Surface Height.  The fire building surface shall be 9 inches (230 mm) minimum above the ground or floor surface.

T307.4  Raised Edge.  Where a raised edge or curb is provided on a fire ring, the combined distance over the edge or curb down to the fire building surface shall be 24 inches (610 mm) maximum.

T308  Cooking Surfaces, Grills, and Pedestal Grills

T308.1  General.  Cooking surfaces, grills, and pedestal grills shall comply with T308.

T308.2  Clear Space.  All usable portions of the cooking surface shall be provided with a clear space complying with T306.4 that is 48 inches (1220 mm) deep minimum measured from the cooking surface and 48 inches (1220 mm) wide minimum.

EXCEPTION:  Where a clear space 48 inches (1220 mm) deep minimum cannot be provided because any of the conditions in T302 applies, the space shall be permitted to be reduced by the minimum necessary but shall not be less than 36 inches (815 mm) deep minimum.

T308.3  Cooking Surface Height.  The cooking surface shall be 15 inches (380 mm) minimum and 34 inches (865 mm) maximum above the ground or floor surface.

T308.4  Operable Parts.  Operable parts shall comply with T407.

T309  Trash and Recycling Containers

T309.1  General.  Trash and recycling containers shall comply with T309.

T309.2  Clear Space.  A clear space complying with T306.4 and T403 shall be provided at trash and recycling containers.

T309.3  Operable Parts.  Operable parts shall comply with T407.

EXCEPTION:  Hinged lids and controls designed for large animal exclusion shall not be required to comply with T407.3.

Advisory T309.3  Operable Parts.  The USDA Forest Service, Technology and Development Center has issued a document which provides information about animal resistant garbage containers.  Suggested designs may be useful in complying with these provisions.
T310  Wood Stoves and Fireplaces

T310.1  General.  Wood stoves and fireplaces shall comply with T310.

T310.2  Clear Space.  All usable portions of the wood stove or fireplace shall be provided with a clear space complying with T306.4 that is 48 inches (1220 mm) deep minimum measured from the wood stove or fireplace and 48 inches (1220 mm) wide minimum.

EXCEPTION:  Where a clear space 48 inches (1220 mm) deep minimum cannot be provided because any of the conditions in T302 applies, the space shall be permitted to be reduced by the minimum necessary but shall not be less than 36 inches (815 mm) deep minimum.

T310.3  Operable Parts.  Operable parts shall comply with T407.

T311  Overlooks and Viewing Areas

T311.1  General.  Overlooks and viewing areas shall comply with T311.

T311.2  Turning Space.  The viewing area shall have a turning space complying with T306.4 and T402.

EXCEPTION:  Where turning spaces cannot be provided because any of the conditions in T302 applies, turning spaces shall not be required.

Advisory T311.2  Turning Space.  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 feet (e.g., around a picnic table) should be at least moderately firm and moderately stable (see Table A in section T303.3 and for more information related to test methods for surface firmness and stability).

T311.3  Unrestricted Viewing Opportunities.  Each location providing viewing opportunities for distinct points of interest shall provide at least one unrestricted viewing opportunity for each distinct point of interest that accommodates eye levels between 32 inches (815 mm) minimum and 51 inches (1295 mm) maximum.

EXCEPTION:  Where unrestricted viewing opportunities cannot be provided because any of the conditions in T302 applies, unrestricted viewing opportunities shall not be required.

Advisory T311.3  Unrestricted Viewing Opportunities.  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 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 an individual seated in a wheelchair or other mobility device with the same view.
T312  Telescopes and Periscopes

T312.1  General.  Telescopes and periscopes shall comply with T312.

T312.2  Clear Space.  A clear space complying with T403 shall be provided at telescopes and periscopes.  Clear spaces shall have a firm and stable surface, and shall have a 1:50 maximum slope in all directions.

EXCEPTION:  Where required for proper drainage, slopes not exceeding 1:33 maximum shall be permitted.

Advisory T312.2  Clear Space.  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 feet (e.g., around a picnic table) should be at least moderately firm and moderately stable (see Table A in section T303.3 and for more information related to test methods for surface firmness and stability).

T312.3  Operable Parts.  Operable parts shall comply with T407.

T312.4  Eye Piece.  The eye piece shall be usable from the seated position for viewing each point of interest.

Advisory T312.4  Eye Piece.  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 a swing away seat or a small step or ring platform attached to the mounting post of the instrument would be useful for persons of short stature or children.
T313  Fixed Benches

T313.1  General.  Fixed benches shall comply with T313.

T313.2  Clear Space.  At least one clear space complying with T306.4 and T403 shall be provided at one end of the bench and the space shall not overlap the clear space required for other elements.  The clear space shall be positioned to allow wheelchair users to be seated shoulder-to-shoulder with an individual seated on the bench.

T313.3  Height.  The top of the seat surface shall be 17 inches (430 mm) minimum and 19 inches (485 mm) maximum above the ground or floor space.

T313.4  Back Support.  Back support shall be provided the full length of the bench.

T313.5  Armrest.  Where required by T213.2, at least one armrest shall be provided on the bench and shall comply with T411.8.

T314  Utility Sinks

T314.1  General.  Utility sinks shall comply with T314.

T314.2  Clear Space.  Clear space complying with T403 shall be provided at utility sinks.  The clear space shall be positioned for a parallel approach.  Clear spaces shall have a firm and stable surface, and shall have a 1:50 maximum slope in all directions.

EXCEPTION:  Where required for proper drainage, slopes not exceeding 1:33 maximum shall be permitted.

T314.3  Height.  The counter or rim shall be 34 inches (865 mm) maximum above the ground or floor surface.

T314.4  Depth.  The bottom of the bowl shall be 15 inches (380 mm) minimum above the ground or floor surface.

T314.5  Operable Parts.  Operable parts shall comply with T407.

T315  Mobility Device Storage Facilities

T315.1  General.  Mobility device storage facilities shall comply with T315.

T315.2  Clear Space.  Clear space complying with T306.4 and T403 shall be provided at storage facilities.

T315.3  Mobility Device Storage.  Storage facilities designed for mobility devices shall be 38 inches (965 mm) high minimum, 28 inches (710 mm) wide minimum and 40 inches (1015 mm) deep minimum.

T315.4  Operable Parts.  Operable parts shall comply with T407.

T316  Pit Toilets

T316.1  General.  Pit toilets shall comply with T316.

T316.2  Clear Space.  Clear space complying with T306.4 and T409 shall be provided at pit toilets.

EXCEPTIONS:  1.  Where clear space complying with T409 cannot be provided because any of the conditions in T302 applies, the clear space shall be permitted to be reduced to 48 inches (1220 mm) by 48 inches (1220 mm) minimum.

2.  Where a clear space 48 inches (1220 mm) by 48 inches (1220 mm) minimum cannot be provided because of any of the conditions in T302 applies, a clear space shall not be required.

T316.3  Height.  The seat height of pit toilets shall comply with T409.4.

T316.4  Grab Bars.  Where the pit toilet is provided with walls, grab bars complying with T411 shall be provided.

T317  Utilities

T317.1  General.  Utilities shall comply with T317.

T317.2  Clear Space.  A 60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum clear space shall be provided at water spouts.  A clear space complying with T403 shall be provided at all other utilities.  Clear spaces shall have a firm and stable surface, and shall have a 1:50 maximum slope in all directions.

EXCEPTION:  Where required for proper drainage, slopes not exceeding 1:33 maximum shall be permitted.

T317.3  Water Spouts.  Water spouts shall be located 28 inches (710 mm) minimum to 36 inches (915 mm) maximum above the ground or floor surface and shall be centered in the clear space required by T317.2.

T317.4  Operable Parts.  Operable parts shall comply withT407.

EXCEPTIONS:  1.  Sewage hookups shall not be required to comply with T407.

2.  Hand pumps shall not be required to comply with T407.3.

T318  Camping Facilities

T318.1  General.  Camping facilities shall comply with T318.

T318.2  Camping Space Parking.  Camping space parking shall comply with T318.2.

T318.2.1  Recreational Camping Vehicle and Trailer Spaces.  Recreational camping vehicle and trailer parking spaces shall be 20 feet (6100 mm) wide minimum.

EXCEPTION:  Where two recreational camping vehicle or trailer spaces are required by T218.2, one space shall be permitted to be 16 feet (4880 mm) wide minimum.

T318.2.2  Tent Camping Spaces and Camp Shelter Spaces.  Where parking is provided within the tent camping spaces or camp shelter spaces, the parking space shall be 16 feet (4880 mm) wide minimum.

T318.2.3  General Use Parking Areas.  Recreational camping vehicle and trailer parking spaces in general use parking areas shall be 12 feet (3660mm) wide minimum, and shall have an adjacent access aisle 8 feet (2440 mm) wide minimum extending the full length of the parking space.  The surface of the parking space and access aisle shall be firm and stable.

T318.2.4  Slope.  Parking spaces shall have a 1:50 maximum slope in all directions.

EXCEPTION:  Where required for proper drainage, slopes not exceeding 1:33 maximum shall be permitted.

T318.3  Tent Pads and Tent Platforms.  Tent pads and tent platforms shall comply with T318.3.

T318.3.1  Clear Space.  A 48 inches (1220 mm) wide minimum clear space shall be provided around the tent pad or tent platform.

EXCEPTION:  Where a 48 inches (1220 mm) minimum wide clear space cannot be provided because any of the conditions in T302 applies, the space shall be permitted to be reduced by the minimum necessary but shall not be less than 36 inches (915 mm) wide minimum.

T318.3.2  Surface.  The surface of tent pads and tent platforms, and the clear space required by T318.3.1 shall be firm and stable.  Tent pad surfaces shall allow use of tent stakes and other securement devices.

EXCEPTION:  Where a firm and stable tent pad surface and clear space cannot be provided because any of the conditions in T302 applies, the surface shall not be required to comply with T318.3.2.

T318.3.3  Slope.  Tent pads and tent platforms, and the clear space required by T318.3.1 shall have a 1:50 maximum slope in all directions.

EXCEPTION:  Where required for proper drainage, slopes not exceeding 1:33 maximum shall be permitted.

T318.3.4  Edge Protection.  Curbs, walls, railing, or projecting surfaces that prevent people from slipping off the tent platform shall be provided.  Curbs shall be 3 inches (75 mm) high minimum.

T318.3.5  Connection.  The surface of the tent platform shall be accessed by either a ramp, by transfer, or directly from the adjacent ground surface.

T319  Warming Huts

T319.1  General.  Warming huts shall provide a turning space complying with T402.  Where doors are provided, they shall comply with T408.

T320  Outdoor Rinsing Showers

T320.1  General.  Outdoor rinsing showers shall comply with T320.

T320.2  Clear Space.  A clear space of 60 inches (1525 mm) diameter minimum shall be provided at outdoor rinsing showers and shall be located so that the water from the shower head is directed toward the center of the clear space.  The clear space shall have a firm and stable surface, and shall have a 1:50 maximum slope in all directions.

EXCEPTION:  Where required for proper drainage, slopes not exceeding 1:33 maximum shall be permitted.

T320.3  Grab Bars.  A grab bar complying with T320.3.1, T320.3.2, or T320.3.3 shall be provided at outdoor rinsing showers.  The grab bar shall also comply with T411.

T320.3.1  Vertical Grab Bar.  Where the shower head is mounted on a post, a vertical grab bar shall be provided under the shower head and shall start 33 inches (840 mm) maximum above the floor and extend to within at least 3 inches (75 mm) of the shower head.

T320.3.2  Circular Grab Bar.  Where the shower head is mounted on a post, a grab bar that surrounds the usable part of the post shall be provided.  The grab bar shall be provided 33 inches (840 mm) minimum to 36 inches (915 mm) maximum above the floor.

T320.3.3  Horizontal Grab Bar.  A horizontal grab bar extending 18 inches (455 mm) minimum in both directions from the center line of the shower head shall be provided under the shower head.  The grab bar shall be provided 33 inches (840 mm) minimum to 36 inches (915 mm) maximum above the floor.

T320.4  Controls.  Controls shall comply with T407.  If self-closing controls are used, the controls shall remain open for at least 10 seconds.

T320.5  Low Shower Spray Head.  A fixed shower spray head shall be provided and shall be located 48 inches (1220 mm) minimum to 54 inches (1370 mm) maximum above the ground or floor.

EXCEPTION:  A hand held shower spray unit complying with T410 shall be permitted.

T320.6  High Shower Spray Head.  A fixed shower spray head shall be provided and shall be located 72 inches (1830 mm) minimum above the ground or floor.

EXCEPTION:  A hand held shower spray unit complying with T410 shall be permitted.

T321  Signs

T321.1  General.  Trail signs shall comply with T321.2 and camping space signs shall comply with T321.3.

T321.2  Trail Signs.  Signs identifying trails and trail segments complying with T303 shall be placed at the trail head and all designated access points.  The signs shall display a symbol designating that the trail or trail segment is accessible, and shall include the total distance of the accessible trail or trail segment and the location of the first point where exceptions from the technical provisions in T303 apply.

Advisory T321.2  Trail Signs.  Accessible trails must be identified by a sign.  While no specific sign was decided on, possible designs for consideration follow.
Four symbols with International Symbol of Accessibility (ISA):  two variations of ISA with hiker;  ISA on bumpy surface; ISA by tree.

Given the wide variability in the actual 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 conditions for all trails will assist users in determining whether the trail meets their own abilities.  The variability of conditions on these trails can be very dramatic, and may range from relatively minor variations from the technical provisions 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.

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 the location of the accessible trail segments and any parts of the trail that are not accessible.  Recommendations for measurement techniques for the individual trail variables are included at the end of this section.  For trails that comply with the technical provisions in T303, it is recommended that the following additional information be provided:

Trail symbol
Running slope (average and maximum)
Cross slope (maximum)
Clear tread width (minimum)
Surface type
Trail length
Trail elevation (at trailhead); and
Maximum elevation attained.

Advisory T321.2  Trail Signs.  For trails that do not comply with the technical provisions in T303, it is recommended that the following information be provided:

Running slope (average and maximum)
Cross slope (average and maximum)
Clear tread width (minimum and average)
Surface type, firmness, and stability
Tread obstacles (magnitude and frequency)
Trail length
Trail elevation (at trailhead)
Total elevation change; and
Maximum and lowest elevation attained.

The following definitions describe how measurements should be made in order to provide the recommended information for trail signage:

  • Surface Information
The type of material that makes up the majority of the surface should be described (e.g., packed soil, asphalt, crushed rock, or 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 Advisory T303.3 Surfaces for information on measuring firmness and stability).
  • Clear Tread Width (minimum and average)
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 T303.4 for additional information on measuring clear tread width).
  • Tread Obstacles
See T303.6 for information on measuring tread obstacles.
  • Slope

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 foot (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 foot 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 one walks down into the rut is 20 percent.  The remaining 7 feet on the right-hand side of the trail has a running slope of 10 percent.  The maximum running slope would be measured as 10 percent.

  • Cross Slope

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 feet (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 inch (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 percent 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 percent.  The maximum cross slope would be measured as 3 percent.

  • Trail Length
The distance from the trailhead to the destination or end of the trail should be measured in linear feet along the center line of the trail.
  • Trail Elevation
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.
Advisory T321.2  Trail Signs.  The following are examples of generic signage formats that include the information recommended in this advisory note.
Happy Falls Trail information card with, profile, width, hazard indentification, etc.  This is a sample of trail information that could be distributed at a visitor center or used as trailhead signage.
Advisory T321.2  Trail Signs.  This is a sample of full trailhead signage that would be printed in full color and could be placed at the beginning of the trail.  It could also be formatted to fit into a fold up pocket guide.
Lower Yosemite Fall Trail map with segments identified, grade profile, location of amenities, etc.  This is a sample of full trailhead signage that would be printed in full color and could be placed at the beginning of the trail.  It could also be formatted to fit into a fold up pocket guide.

T321.3  Camping Space Signs.  Camping spaces complying with T318 shall be identified by the International Symbol of Accessibility complying with T412.

T322  Protruding Objects

T322.1  General.  Protruding objects on trails, outdoor recreation access routes, and beach access routes shall comply with T405.  Trails shall have 80 inches (2030 mm) high minimum vertical clearance.

EXCEPTION:  Where 80 inches (2030 mm) high minimum vertical clearance cannot be provided on trails because any of the conditions in T302 applies, vertical clearance shall be permitted to be less than 80 inches (2030 mm) high minimum where a barrier is provided.

Advisory T322.1  Protruding Objects. When the vertical clearance is less than 80 inches on a trail, a barrier is needed to warn persons who are blind or visually impaired.