why we assess

federal standards, best practices, and our story

why we assess

federal standards, best practices, and our story

reasons for trail assessment

A happy hiker is an informed hiker. Knowing the makeup of a trail allows individuals and families to better determine whether or not a particular trail will meet their needs. Objective trail data is essential in providing access and inclusion for people of all abilities. Park and land managers are also better equipped to maintain and improve their trail system in order to ensure a better, safer, and more enjoyable environment, as well as conform to federal guidelines. By assessing trails, all critical trail characteristics are inventoried, thus enabling a clear way forward for everyone.

The following information lays out the primary reasons for performing a trail assessment.

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beginnings

assessment history

1991: objective trail characteristics

Existing trail rating systems using subjective descriptions such as “difficult” do not give users the information they needed to safely attempt a hike. In 1991, Beneficial Designs conducted a pilot study in Yellowstone National Park and the Gallatin National Forest, in order to identify specific objective trail characteristics which would provide hikers of all abilities the necessary information to make adequate safety and equipment preparations as well as decide whether or not to hike a trail. These characteristics include grade, cross slope, tread width, surface firmness and stability, and the presence, dimensions, and locations of obstacles.

project goal

Beneficial Designs received funding* in 1993 to create a universal mapping system to communicate detailed and pertinent information about individual trails. The information was designed to be useful to anyone who might want to hike a trail, regardless of their hiking ability.

1993 - phase 1: the beginning of the universal trail assessment process (UTAP)

Beginning in Yellowstone National Park and the Gallatin National Forest, along with professionals from the National Park Service, the USDA Forest Service, and volunteers from several states, Beneficial Designs performed trail assessments for the first time in July and August of 1993. The assessments resulted in many improvements to data forms and the measuring process, in addition to valuable input regarding map layout and information content.

1994 - phase II: training trail assessment coordinators

In September 1994, Beneficial Designs again received funding* in order to train and certify trail assessment coordinators to conduct their own trail assessments. Trail data collected during the assessments was processed into trail access information, including a grade profile and summary of average and extreme grades, cross slopes, and trail widths. The trail assessment process expanded to collect trail maintenance data useful to trail managers.

trail access information (TAI)

Since that time, the collected data from trail assessments has been displayed in many formats in order to present objective trail access information to the public. A range of options have been designed to help people with a variety of abilities obtain hiking information, including pocket maps, trailhead maps, trailhead signage, audio trail descriptions, and more recently GIS maps and data. The visual formats, conforming to accessibility standards, utilize a combination of universal symbols, general and detailed written information, grade illustrations, and overhead route schematics to convey trail access information to visitors. In addition, audio descriptions of a trail for persons with vision impairments can now be distributed electronically via a link with Trail Access Information (TAI).

*acknowledgments

This project was funded by the National Center for Medical Rehabilitation in the National Institute of Child Health and Human Development at the National Institutes of Health through Small Business Innovation Research Phase I Grant #1 R43 HD29992-01 and Phase II Grant #2 R44 HD29992-02.

the process

five trail access characteristics

During the 1991 pilot study conducted in Yellowstone National Park and Gallatin National Forest, Beneficial Designs identified five characteristics of a trail that greatly affect access. A system to collect and publicly display information about grade, cross slope, surface type, obstacles, and trail width was developed into the Universal Assessment Process to help make trail systems more accessible to users of all abilities. These five elements are the foundation for all methods of Beneficial Designs trail assessment.the

trail length

The type of surface found in between stations is recorded, as well as a description of its characteristics.
Trail surface type is a major influence on the degree of access for all user groups.

surface quality

The type of surface found in between stations is recorded, as well as a description of its characteristics.
Trail surface type is a major influence on the degree of access for all user groups.

tread width

A tape measure is used to measure the width of the trail. The minimum tread width, or “beaten path,” is measured at each station and is used to calculate the typical tread width. The minimum amount of usable passage space between stations, or minimum clearance width, is also measured.

Objective information about the width of the trail and the locations of the narrowest sections is critical for people who use mobility devices such as strollers, walkers, and wheelchairs. The average manual wheelchair has a wheelbase width of less than 28 inches. If a trail narrows to 26 inches, persons in a 28-inch wheelchair will know that they will not be able to venture past this point unless they are capable of transferring out of their chair and maneuvering their chair through this narrow location. If the width of the trail is disclosed, mobility device users will be able to determine before embarking on a trail exactly how far they will be able to hike and whether they will be able to reach their destination.

grade

The average grade between two designated stations along the trail is measured with a clinometer. These measurements are then used to compute the typical grade for the entire trail. Short, steep sections are measured with a Smart Tool level and recorded as maximum grade sections. The Smart Tool level is 24 inches in length and thus measures the grade as it would be experienced over the course of a single stride, or by a stroller or wheelchair.

Information about the maximum grade sections found on a trail is used to add detailed information to maps. The typical and maximum grades are displayed with the grade symbol to convey this pertinent information on TAI Strips and trailhead signage.

Objective information about the typical and maximum grade is very useful to all user groups, especially mountain bike riders and persons with mobility limitations, including older persons and those that use canes, crutches, walkers or wheelchairs. 

cross slope

Cross slope is measured at designated stations along the trail with a 24-inch inclinometer. These measurements are then used to compute the typical cross slope for the entire trail. Similar to maximum grade, steep cross slope sections are measured with an inclinometer and recorded as maximum cross slope sections.

This information is used to add detailed information to maps. The typical and maximum cross slopes are displayed with the cross slope symbol to convey this pertinent information on TAI Strips and trailhead signage.

Cross slope information is most useful to wheelchair users. Wheelchairs are very difficult to drive or maneuver on steep cross slopes.

the Law

federal standards

Although federal standards for trail accessibility currently apply only to federal outdoor developed areas, the United States Access Board intends to establish additional standards for all non-federal outdoor developed areas under the Americans with Disabilities Act (ADA). The Architectural Barriers Act (ABA) Accessibility Standards provides the federal guidelines for the construction and alteration of these areas, which will soon become law for all state and local governments as well as private entities covered by the ADA. In keeping with best practices and compliance with future standards, accessibility guidelines should be incorporated into the design and alteration of all trails to the extent practicable (or reasonably doable under the circumstances), whether or not those trails currently fall under the ABA or not.

The following information regarding ABA Accessibility Standards compliance can be found in more detail at the US Access Board website.

ABA trail definition

The ABA Accessibility Standards defines a trail as “a pedestrian route developed primarily for outdoor recreational purposes. Pedestrian routes that are developed primarily to connect accessible elements, spaces, and buildings within a site are not a trail” [F106.5]. The Appendixes of The Outdoor Developed Areas: A Summary of Accessibility Standards for Federal Outdoor Developed Areas May 2014 states:

A trail typically is not parallel to a roadway and is designed primarily for recreational purposes. Trails are not necessarily part of an infrastructure connecting elements or facilities, but typically are designed to provide a recreational experience. Trails may also be used by multiple types of users, but most are not designed for bicycles, nor do they have a transportation purpose.

which trails must comply with ABAAS?

Two questions determine which trails must comply with the technical requirements of the ABA Accessibility Standards.

  1. Is the trail designed for hiker or pedestrian use?
  2. Is the trail connected to a trailhead or an existing trail that substantially meets the technical requirements for trails?

If the answer to those two questions is yes, then the trail must comply to the extent practicable.
However, the technical requirements for trails under the ABA applies only when trails are altered or newly constructed.
The Summary, commenting on F247.2, states:

When the original design, function, or purpose of an existing trail is changed, regardless of the reason, and the altered portion of the trail directly connects to a trailhead or another trail that substantially meets the technical requirements for trails, the altered portion of the existing trail must comply with the technical requirements for trails.

This does not apply to all types of maintenance. Advisory F247.2 states: “Routine or periodic maintenance activities that are performed to return an existing trail to the condition to which the trail was originally designed are not required to comply…”

Of course, in any outdoor environment, limitations may prevent compliance with the standards. When a condition for exception does exist, the trail is only required to comply to the extent practicable, or reasonably doable under the circumstances.

The four conditions for exception may be found at the US Access Board website.

ABA technical requirements for trails

1017.2 Surface. The surface of trails, passing spaces, and resting intervals shall be firm and stable.

Advisory 1017.2 Surface. A firm trail surface resists deformation by indentations. A stable trail surface is not permanently affected by expected weather conditions and can sustain normal wear and tear from the expected uses between planned maintenance.

1017.3 Clear Tread Width. The clear tread width of trails shall be 36 inches (915 mm) minimum.

1017.4 Passing Spaces. Trails with a clear tread width less than 60 inches (1525 mm) shall provide passing spaces complying with 1017.4 at intervals of 1000 feet (300 m) maximum. Where the full length of a trail does not fully comply with 1017, a passing space shall be located at the end of the trail segment that fully complies with 1017. Passing spaces and resting intervals shall be permitted to overlap.

Advisory 1017.4 Passing Spaces. Entities should consider providing either a 60 inches (1525 mm) minimum clear tread width or passing spaces at shorter intervals if the clear tread width is less than 60 inches (1525 mm), where a trail is:

    • Heavily used; or
    • A boardwalk or otherwise not at the same level as the ground surface adjoining the trail.

Where the full length of the trail does not fully comply with 1017, locating a passing space at the end of the trail segment that fully complies with 1017 enables a person who uses a mobility device to turn and exit the trail.

1017.4.1 Size. The passing space shall be either:

    1. A space 60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum; or
    2. The intersection of two trails providing a T-shaped space complying with 304.3.2 where the base and the arms of the T-shaped space extend 48 inches (1220 mm) minimum beyond the intersection. Vertical alignment at the intersection of the trails that form the T-shaped space shall be nominally planar.

Advisory 1017.4.1 Size. Where the passing space is the intersection of two trails, the intersection must be as flat as possible so that all of the wheels of a mobility device touch the ground when turning into and out of the passing space

1017.5 Tread Obstacles.Tread obstacles on trails, passing spaces, and resting intervals shall not exceed 1/2 inch (13 mm) in height measured vertically to the highest point.

EXCEPTION: Where the surface is other than asphalt, concrete, or boards, tread obstacles shall be permitted to not exceed 2 inches (50 mm) in height measured vertically to the highest point.

Advisory 1017.5 Tread Obstacles. The vertical alignment of joints in concrete, asphalt, or board surfaces can be tread obstacles. Natural features such as tree roots and rocks within the trail tread can also be tread obstacles. Where possible, tread obstacles that cross the full width of the trail tread should be separated by a distance of 48 inches (1220 mm) minimum.

1017.6 Openings. Openings in the surface of trails, passing spaces, and resting intervals shall not allow the passage of a sphere more than 1/2 inch (13 mm) in diameter.

Advisory 1017.6 Openings. Elongated openings should be placed so that the long dimension is perpendicular, or as close to perpendicular as possible, to the dominant direction of travel.

1017.7 Slopes. The slopes of trails shall comply with 1017.7.

1017.7.1 Maximum Running Slope and Segment Length. Not more than 30 percent of the total length of a trail shall have a running slope steeper than 1:12 (8.33%). The running slope of any segment of a trail shall not be steeper than 1:8 (12%). Where the running slope of a segment of a trail is steeper than 1:20 (5%), the maximum length of the segment shall be in accordance with Table 1017.7.1, and a resting interval complying with 1017.8 shall be provided at the top and bottom of each segment.

Table 1017.7.1 Maximum Running Slope and Segment Length

Running Slope of Trail Segment Maximum Length of Segment
Steeper thanBut not Steeper than 
1:20 (5%)1:12 (8.33%)200 feet (61 m)
1:12 (8.33%)1:10 (10%)30 feet (9 m)
1:10 (10%)1:8 (12%)10 feet (3050 mm)

Advisory 1017.7.1 Maximum Running Slope and Segment Length. Gradual running slopes on trails are more useable by individuals with disabilities. Where the terrain results in steeper running slopes, resting intervals are required more frequently. Where running slopes are less severe, resting intervals are permitted to be further apart.

1017.7.2 Cross Slope. The cross slope shall be not be steeper than 1:48.

EXCEPTION: Where the surface is other than concrete, asphalt, or boards, cross slopes not steeper than 1:20 shall be permitted when necessary for drainage.

1017.8 Resting Intervals. Resting intervals shall comply with 1017.8.

1017.8.1 Length. The resting interval length shall be 60 inches (1525 mm) long minimum.

1017.8.2 Width. Where resting intervals are provided within the trail tread, resting intervals shall be at least as wide as the widest segment of the trail tread leading to the resting interval. Where resting intervals are provided adjacent to the trail tread, the resting interval clear width shall be 36 inches (915 mm) minimum.

1017.8.3 Slope. Resting intervals shall have slopes not steeper than 1:48 in any direction.

EXCEPTION: Where the surface is other than concrete, asphalt, or boards, cross slopes not steeper than 1:20 shall be permitted when necessary for drainage.

1017.8.4 Turning Space. Where resting intervals are provided adjacent to the trail tread, a turning space complying with 304.3.2 shall be provided. Vertical alignment between the trail tread, turning space, and resting interval shall be nominally planar.

1017.9 Protruding Objects. Constructed elements on trails, passing spaces, and resting intervals shall comply with 307.

Advisory 1017.9 Protruding Objects. Protruding objects on trails, passing spaces, and resting intervals can be hazardous for individuals who are blind or have low vision. Signs and other post mounted objects are examples of constructed elements that can be protruding objects.

best practice

United States Forest Service guidelines

The Access Board’s federal accessibility guidelines represent the minimum accessibility standards. While compliance with federal standards is mandatory to the extent practicable, exceeding accessibility standards for the purpose of higher levels of accessibility and usability is encouraged.

The US Forest Service has published accessibility guidelines which, according to page 3 of the Forest Service Trail Accessibility Guidelines, provide “guidance for maximizing accessibility of trails in the National Forest System, while protecting the unique characteristics of their natural setting.” While these standards are not legally enforceable outside the scope of the National Forest System, the following guidelines represent best practice for universal trail design.

The US Forest Service outdoor recreation area accessibility guidelines are divided into two documents: the Forest Service Trail Accessibility Guidelines (FSTAG) and the Forest Service Outdoor Recreation Accessibility Guidelines (FSORAG). The information below will focus on trail guidelines found in the FSTAG.

USFS trail definition

Both the FSTAG and FSORAG define a trail by stating the following:

For purposes of the FSTAG and FSORAG, a trail is a pedestrian route developed primarily for outdoor recreational hiking purposes. A pedestrian route provided primarily to connect elements, spaces, or facilities within a site is not a trail; it is an outdoor recreation access route (ORAR).

It is important to note that a trail which meets the accessibility guidelines should not be labelled an “accessible trail.”
The USFS states:

“Accessible Trail” is a term to avoid. The technical provisions in section 7.4 of the FSTAG allow for grades up to 12 percent. While such grades are understandable in challenging terrain as hiking paths selected by choice, the general public’s expectation of an “accessible” pathway is that it have a gentle grade and other uniform factors. In addition, most trails constructed under the FSTAG use exceptions to some extent in order to maintain the nature of the setting.

Therefore, a trail that has been constructed in accordance with the FSTAG should be advertised as a “trail that complies with the trail accessibility guidelines”, rather than as an “accessible trail”. Information concerning grades, etc. is to be posted along with other trail information on websites, trailhead signs, and so forth. Each visitor can then select the trail that best meets their recreation experience and expectations.

which trails must comply with FSTAG?

According to the FSTAG, National Forest System trails must comply with the FSTAG if the following criteria are met:

  1. The trail is new or altered (an alteration is “a change in the original purpose, intent, or function of a trail”).
  2. The trail has a Federal Trail Data Standard (FTDS) designation Designed Use of Hiker/Pedestrian.
  3. The trail connects directly to a trailhead or to a trail that currently substantially complies with the FSTAG.

The FSTAG goes on to state:

These guidelines do not apply to maintenance work (routine or periodic repair of existing trails, recreation sites, or facilities). Where existing individual site features are altered but the floor or ground surface under or around them is not altered, the clear floor or ground space shall not be required to comply with surface and slope requirements.

Of course, in any outdoor environment, limitations may prevent compliance. More information regarding the exceptions to the guidelines may be found in the Forest Service Trail Accessibility Guidelines, section 7.1 and 7.2.

USFS technical requirements for trails

7.4.1 Surface.
The trail tread surface, including resting intervals and passing spaces, shall be both firm and stable.

7.4.2 Clear Tread Width.
The clear tread width of the trail shall be at least 36 inches (915 mm).

EXCEPTION: Where a condition for an exception prevents achieving the required width, the clear tread width may be reduced to 32 inches (815 mm) minimum. If the condition for an exception prevents achieving the reduced width of 32 inches, comply to the extent practicable.

7.4.3 Slope.
Trail running slopes (grades) and cross slopes shall comply with sections 7.4.3.1 and 7.4.3.2.

7.4.3.1 Running Slope (Grade). The running slope (grade) of trail segments shall comply with this section and shall be consistent over the distances cited.

    • Trail running slope (grade) of up to 1:20 (5 percent) is permitted for any distance.
    • The running slope of any segment of a trail shall not be steeper than 1:8 (12 percent).
    • No more than 30 percent of the total trail length may exceed a running slope (grade) of 1:12 (8.33 percent).
    • Where the running slope (grade) of a segment of a trail is steeper than 1:20 (5 percent), the maximum length of the segment shall be in accordance with Table 7.4.3.1, and a resting interval complying with 7.4.4 shall be provided at each end of the segment.

Table 7.4.3.1 Running Slope (Grade) and Resting Intervals

Running Slope of Trail Segment Maximum Length of Segment
Steeper thanBut not Steeper thanBetween Resting Intervals
1:20 (5%)1:12 (8.33%)200 feet (61 m)
1:12 (8.33%)1:10 (10%)30 feet (9 m)
1:10 (10%)1:8 (12%)10 feet (3050 mm)

7.4.3.2 Cross Slope. The cross slope shall not exceed 1:20 (5 percent). Where the surface is paved or is elevated above the natural ground, the cross slope shall not be steeper than 1:48 (2 percent).

7.4.4 Resting Intervals.
Resting intervals shall comply with 7.4.4. Where the trail grade exceeds 1:20 (5 percent), resting intervals shall be provided as specified in Table 7.4.3.1.

7.4.4.1 Length. The resting interval length shall be 60 inches (1525 mm) long minimum.

7.4.4.2 Width. Where resting intervals are provided within the trail tread, resting intervals shall be at least as wide as the widest segment of the trail tread leading to the resting interval. Where resting intervals are provided adjacent to the trail tread, the resting interval clear width shall be 36 inches (915 mm) minimum.

7.4.4.3 Slope. The slope of a resting interval shall not exceed 1:20 (5 percent) in any direction. Where the surface is paved or is elevated above the natural ground, the slope shall not be steeper than 1:48 (2 percent) in any direction.

7.4.4.4 Turning Space. Where resting intervals are provided adjacent to the trail tread, a turning space complying with ABAAS section 304.3.2 shall be provided. Vertical alignment between the trail tread, turning space, and resting interval shall be nominally level. The trail tread, turning space, and resting interval may overlap.

7.4.5 Passing Spaces.
Trails with a clear tread width less than 60 inches (1525 mm) shall provide passing spaces complying with 7.4.5 at intervals of 1000 feet (300 m) maximum. A passing space must also be provided at the end of any segment of trail that meets the requirements of 7.4, if the full length of the trail does not meet the requirements. Passing spaces and resting intervals may coincide or overlap.

7.4.5.1 Size. The passing space shall be either:

    • A space 60 inches (1525 mm) minimum by 60 inches (1525 mm) minimum; or
    • The intersection of two trails providing a T-shaped space complying with ABAAS section 304.3.2 where the base and the arms of the T-shaped space extend 48 inches (1220 mm) minimum beyond the intersection. Vertical alignment at the intersection of the trails that form the T shaped space shall be nominally level.

7.4.5.2 Slope. The cross slope of a passing space shall not exceed 1:20 (5 percent) in any direction.

7.4.5.3 Non-complying Segment Ends. Where a segment of the trail does not comply with 7.4, a passing space shall be located at the end of each adjacent trail segment that does comply with 7.4.

7.4.6 Tread Obstacles.
Tread obstacles on trails shall not exceed 2 inches (50 mm) in height measured vertically to the highest point. Where the trail surface is paved or is elevated above the natural ground, tread obstacles shall not exceed ½ inch (13 mm) in height measured vertically to the highest point.

7.4.7 Openings.
Openings in trail tread surfaces, trail resting spaces, and trail passing spaces shall be small enough to prevent passage of a 1/2 inch- (13 mm-) diameter sphere. Where possible, elongated openings should be placed perpendicular, or as close to perpendicular as possible, to the dominant direction of travel.

Exception. Where openings that do not permit the passage of a ½ inch (6.4 mm) sphere cannot be provided due to a condition for an exception, openings that do not permit passage of a ¾ inch (19 mm) sphere shall be permitted.

7.4.8 Protruding Objects.
Constructed features, including signs, shall not extend into the trail tread more than 4 inches (100 mm) between 27 inches (685 mm) and 80 inches (2030 mm) above the surface of the trail.

7.4.9 Trail Facilities.
Where provided on trails, facilities shall comply with the applicable provisions of the FSORAG. ORARs are not required at or between facilities on trails.

Exception. When the surface of the required clear ground space for trail facilities is not paved or is not elevated above the natural ground, slopes not steeper than 1:20 (5 percent) shall be permitted where necessary for drainage.

7.4.10 Trailheads.
Trailheads shall comply with 7.4.10.

7.4.10.1 Outdoor Constructed Features. Where provided within trailheads each outdoor constructed features such as parking spaces, toilets, or camp sites shall comply with the applicable portions of the FSORAG and ABAAS.

7.4.10.2 Outdoor Recreation Access Routes (ORARs). At least one outdoor recreation access route complying with FSORAG section 2.0 shall connect the following places at trailheads:

    • Accessible parking spaces or other arrival point;
    • Starting point of the trail; and
    • Accessible outdoor constructed features, elements, spaces, and facilities within the trailhead.

Exception 1. In alterations to existing trailheads, where a condition for exception prohibits compliance with a technical provision, the ORAR shall comply with FSORAG 2.0 to maximum extent practicable.

Exception 2. Where elements, spaces, or outdoor constructed features are altered at trailheads but the circulation path is not altered, an outdoor recreation access route shall not be required.

7.4.11 Trailhead Signs.
Where new trailhead information signs are provided at trailheads on newly constructed or altered trails, they shall comply with 7.4.11.

7.4.11.1 Clear Space. Where new trailhead information signs are provided at trailheads on newly constructed or altered trails, they shall comply with 7.4.11.

7.4.11.2 Sign Contents. ed at trailheads on newly constructed or altered trails, regardless of whether the trail is accessible, the signs shall include at  minimum the following information:

    • Length of the trail or trail segment
    • Surface type
    • Typical and minimum tread width
    • Typical and maximum running slope
    • Typical and maximum cross slope
    • A statement that the posted information reflects the condition of the trail when it was constructed or assessed, including the date of the construction or assessment

Where more extensive trail information is provided (e.g., an aerial map of the trail and related facilities), the location of specific trail features and obstacles that do not comply with the technical provisions in 7.4 should be identified and a profile of the trail grade should be included.

7.4.11.3 Reach Ranges. If materials need to be obtained from or manipulated on a sign or kiosk, the sign or kiosk shall be designed to meet the reach ranges in section 308 of the ABAAS.

7.4.12 Gates and Barriers.
Where gates or barriers are constructed to control access to trails, gates and barriers shall comply with 7.4.12.

7.4.12.1 Clear Width. Gate openings and openings in barriers for hiker passage shall provide a clear width of 36 inches (915 mm), complying with ODAAG, section 1017.3 Clear Tread Width.

7.4.12.2 Gate Hardware. Gate hardware shall comply with operable controls requirements in ABAAS section  309.4 and 404.2.7.

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