Hello. Please sign in!

National Trail Surfaces Study

Part II. National Trail Surface Survey Final Report

I. Introduction

Purpose

In a collaborative effort between the U.S. Access Board, the National Center on Accessibility, and Oklahoma State University, researchers sought to provide qualified professionals, resource specialists and operations staff of parks and other recreational properties with trails in the United States with descriptive and/or comparative information about the status of construction practices of pedestrian/hiker, natural surface trails The purpose of the survey research study was to gain insight from professionals affiliated with trail management pertaining to trails’ construction, repair, and maintenance activities. This study’s objective was to gather information about current natural surface trail construction, the products or applications used on the trails’ surfaces, and the effectiveness of the surfaces to last.

Background

The diversity of trails in this country is only matched by the diversity of environments in which they are located. A surface that might be firm and stable in one region of the country may be not firm and not stable in another; a surface that may be firm and stable in July may be not firm and not stable in December; and a surface that was firm and stable last year, may be not firm and not stable this year. These are just a few of the problems faced by Land Managers who are trying to make decisions on natural surfacing materials that create a firm and stable trail. Currently, there are not enough answers to provide to Land Managers because qualitative data on existing natural surface trails has not been compiled and distributed for specific regions.

As previously reported, the original intent of the National Trail Surface Study was to gather longitudinal data on different natural trail surface materials across a variety of regions throughout the United States to determine the impact of climatic influences and their effect on firmness and stability of those surfaces over time. Owing to the downturn in economic and human resources starting in 2008, parks that had previously committed to participate in the study withdrew, leaving only the original site (Bradford Woods) for testing over the 51 months data were collected. In an effort to gain insight into the types of natural surface materials being used on trails nationally, the researchers proposed a new course of study to gather data via survey method. The new scope of work was to conduct a study of trail managers to gain information on trail construction, repair, and maintenance. The intended outcome was to establish and maintain a database of regionally relevant information on trail surface materials and construction practices. Oklahoma State University was commissioned in 2011 to develop and conduct a survey of trail managers to ascertain information about natural trail surface materials, and construction practices used in different region of the country. The accessibility of the trails and surface materials were not a focus of this survey.

II. Research Methodology

Beginning in 2010 NCA and the Access Board began strategizing on how to provide a useful resource to trail managers on what natural surface materials were being used regionally across the country, and what maintenance issues were associated with different surface materials. There was increasing interest and demand for information about what natural surface materials would be blend into various environments, be eco‐friendly, suitable in different climates, terrains, and remain firm and stable for visitors with disabilities. The creation of a database to which information could be initially populated through a survey of trail managers, maintenance issues updated at least semi‐annually and available for use by the public was the desired outcome.

Prior to participating in this survey, prospective participants were advised to spend some time gathering information pertaining to research elements (trail’s geographic information, surface product information, decisions related to trails etc.). Initially, it was decided that the survey would run for four (4) rounds; however results from the first round made it evident to the research team and the funding agencies that modifications were necessary not only pertaining to the initial instrument, but to the targeted populations. Therefore, a new database, which consisted of the names of all Recreational Trails Program administrators, was constructed based on a contact list with email addresses which was posted on the website of American Trails Organization. Additionally, the research team was able to gather new contact information of trail professionals through networking in a conference. In total, three panels of prospective professionals were created.

Selection of Methodology

The National Center on Accessibility subcontracted with Oklahoma State University (OSU) to develop a research methodology to collect initial data from which a database of trails could be established and to which data could be added and updated over time. A repeated survey measurements method was chosen by which survey respondents would initially complete survey questions within eight research sections:

SECTION #1 Geographic, demographic, and political information (type of management agency, park location, trail name, age of trail, length of trail, traffic on trail, and similar data)

SECTION #2 Trail surface composition (e.g. natural, native, aggregate, soil stabilizer, etc.) information (product type, manufacturer name, warranty/guarantees’ information, and similar data)

SECTION #3 Trail pre‐installation specifications (soil type/composition, slope of surface)

SECTION #4 Sub‐base installation (date of installation, aggregate type used, aggregate depth, installation contractor, and similar data)

SECTION #5 Trail surface installation (date of installation, aggregate type used, aggregate depth, installation contractor, and similar data)

SECTION #6 Maintenance since installation (length of time between installation and first repair, cause for first repair, number of complete replacements, condition of trail’s surface over time)

SECTION #7 Quarterly maintenance (number of maintenance activities performed during the last quarter, condition of the trail during the last quarter, and occurred unusual events)

SECTION #8 Photographs of the trail and surrounding environment

Once completed, respondents would then receive a request to update data quarterly on sections 7 and 8 (maintenance issues and photographs of trail changes). The repeated measurements method would allow for a longitudinal view of changes in natural trail surfaces over time.

Selection of Participants

The principal investigators at OSU were to pilot test the survey instruments with professional contacts in parks and recreation that manage pedestrian trails designed, developed, and maintained with the natural surface materials or applicable bonded synthetic materials. These professional practitioners were in communities and agencies located in Oklahoma, north Texas, western Arkansas, and southern Kansas. The survey was originally developed in the SurveyGizmo platform. The final survey was administered in the Qualtrics platform. Appendix E provides the survey, as it was distributed through OSU Qualtrics.

Requests for participation in the survey were announced through the American Trails website, contacts with national trail or accessibility coordinators in the National Park Service, U.S. Forest Service, and Bureau of Land Management.

III. Results of the Study

Two hundred fifty-three professionals were sent the survey, 154 (61%) of which accessed the survey. Prospective participants were asked to answer questions pertaining to inclusion criteria set by the researchers and the funding agencies–whether the trail was predominately pedestrian/hiker and the trail surface was other than asphalt, concrete or boardwalk. Among those who accessed the survey, only 104 professionals were eligible to participate. For a survey for which participation was estimated not to exceed twenty (20) minutes, the duration mean was documented to be 11 hours and 39 minutes. This probably includes considerable time away from the computer during which time the survey remained “open” on the user’s site.

The rate of full completion of the survey questions was extremely low yielding spotty results for comparison. Of the surveys submitted thirty‐nine provided adequate (albeit not complete) basic information related to surface materials types and construction and were extracted for further examination. Responses were received from across the country and from a variety of agency types with the majority coming from state/local government and federal entities (Table 7).

Table 7.  Agency Representation of Respondents
Agency n Percent
City agency 2 5.1%
County agency 5 12.8%
State agency 10 25.6%
Federal agency 19 48.7%
Non-profit organization 3 7.7%
Total 39 100%

Respondents were asked if the trail on which they reported was designated as accessible. Table 8 shows that of the qualified surveys, 15 indicated their trail was accessible. However, no other defining information (slopes, tread obstacles, etc.) is available to support the level of accessibility of these trails.

Table 8. Accessible Trail Designation
Accessible Trail? n Percent
Yes 15 38.5%
No or unknown 24 61.5%
Total 39 100%

The geographic distribution of qualified respondents were scattered across the United States. Figure N illustrates the location of participating trails in twenty‐two states and the District of Columbia.

Needed

Figure N. Regional Distribution of Trail

Of the thirty-nine trails reviewed, ninety-two percent used naturals trail surface materials without stabilizers and only 7.7 percent used a stabilizer product. Table 9 shows that the predominant types of trail materials used were either Native/Natural soils (43.6%) or Crushed Rock/Aggregate (51.3%). Interestingly, however, a general observation notes that for trails that were designated as accessible, the trail material used was overwhelmingly Crushed Rock (93%) vs. Native/Natural soils (7%).

Table 9. Type of Surface Material Used
Surface Material n Percent
Aggregate w/stabilizer 3 7.7%
Aggregate w/o stabilizer 17 43.6%
Native/natural soil w/o stabilizer 17 43.6%
Soil w/ high organic content 2 5.1%
Total 39 100%

When asked if the respondent would recommend the trail surface material used, nineteen respondents indicated that they would (48.7%) . Table 10 shows the surface materials recommended by region and surface composition. Also included are comments provided by respondents about the trail surface or maintenance related issues.

Table 10. Surface Materials Recommended by Region
Region Location Surface Material Comments
ALASKA REGION      
  AK Tek Mix First repair was a result of 1" rocks coming to the surface. Rocks were gathered and eliminated. The natural "tek mix" which is processed on site compacts really well and has a very long life span.  It is a 3/4 inch minus mix consisting of sand gravel, and other natural occurring materials. Trail resurfaced in 2012 with natural and non-natural surfaces.
  AK Naturally occurring glacial moraine & Geotextile Fabric Underlay We have had amazing success with this trail.  The success is largely because of the type of material we are fortunate to work with.  However, the use geotextile is imperative to the trails lasting stability as well. The trail required annual maintenance due to uneven wear.
  AK D−1 minus base crushed aggregate; 1/2" minus top dress With a base of D−1 or larger aggregate and then the addition of 1/2" minus binds the trail with all the fines. With mechanical compaction, the trail can set up.
MIDWEST REGION      
  IA Crushed Limestone The trail has instances of uneven wear, ruts and washout/runoff quarterly that requires maintenance. Overall the trail is cheap and easy to maintain.
  OH Cohesive soil, dry soil, moist soil Trail tread renovations involved rebenching native in-place subsoil materials. In our experience we have found that the performance of a natural soil trail surface depends entirely on the slope and alignment and management of water on the trail surface.
  KY Cohesive Soil The trail required maintenance due to erosion of the trail tread due to washout/runoff. The trail is maintained for washout/runoff and ruts annually. The surface has been replaced one time to lessen erosion.
  KY Dry and granular soils and mulch pine By using the native soil along with added mulch pine stabilizer the maintenance has held. Trail is easier to use and is being used more often. Stone cribbing was used to increase drainage.
NORTHEAST REGION      
  CT Crushed Rock and stone dust The trail has instances of washout/runoff annually and has been repaired for erosion. Ruts have been created in the surface resulting from illegal ATV/motorcycle use. Trail material is cheap and low maintenance.
  VA Klingstone 400 Trail is an excellent surface. Finding a contractor for installation was difficult. Trail has instances of chipping along the edge quarterly.
  MA 1/2" crusher run 100% crusher run material at 1/2" size compacts very well and holds up extremely well to New England weather. The trail has instances of settling annually.
  DE Crushed rock and fines We believe, if built properly, stone trails can be very sustainable. This trail has instances of washout/runoff quarterly.
  VA Crushed rock with Gravel Pave II Originally constructed unsuccessfully as a natural aggregate trail due to washout. Soil Sement was applied for several years but resulted in washout during minor rains.  Now Gravel Pave II is being applied to the areas most prone to wash out.  While additional materials need to be replenished after a storm, the base of the trail remains intact. Gravel Pave II was selected based on previous use in the Park on a steeper trail, however it penetrates the surface and should be selected with care (in terms of aesthetics) in any historically significant areas.
  NE Sand and 1" minus river run aggregate It is difficult working with a sand sub-base, so any correspondence with other groups on what they have tried may become a benefit here.  This trail is in the heart of the Sand hills. The trail has instances of uneven wear, ruts and washout/runoff.
WESTERN REGION      
  CA Crushed rock Inexpensive and easily maintained surface material, one drawback is that the surface is not firm and stable enough for strollers or wheelchairs. Trail has instances of ruts and washout/runoff annually.
  UT Crushed rock The gravel used as the tread surface was primarily rounded particles, which have worked their way to the surface forming a loose layer of pebbles. The tread gravel material should have been an angular rock 3/4" minus with a good component of fines to bind the material together. This coming field season the trail will be capped with a different type of gravel to allow for a solid tread surface. The trail has instances of settling and washout/runoff annually.
  NV Decomposed Granite While a decomposed granite surface aesthetically conforms to a natural desert environment, it requires frequent maintenance.  In an economy where staffing is minimal, local governments may find this type of surface undesirable.
  CA Crushed rock with clay soil fines A dirty 3/4" or 3/8" road base with around 20 −30 percent clay fine particles seems to work well in areas that are not consistently wet. The trail has instances of ruts and weeds annually.
  UT Native soil and crushed limestone The type of soil and geological configurations are very unique and pose difficulties in keeping a trail on a continually eroding area. The trail has instances of uneven wear monthly and ruts and washout/runoff quarterly.
  NV Natural/native soils and rock This trail material was selected based on the TRTA, USFS and NV State Parks transition to building trails with a purposeful aim toward sustainability. This trail has instances of uneven wear, settling, ruts and washout/runoff annually.

Five respondents indicated they would not recommend the trail surface and those responses are found in Table 11. Also included are comments provided by respondents about the trail surface or maintenance related issues. Fifteen respondents did not provide a response.

Table 11. Trail Surfaces Not Recommended by Region
Region Location Surface Material Comments
MIDWEST REGION      
  MN Crushed limestone The trail has instances of uneven wear, ruts and washout/runoff annually.
NORTHEAST REGION      
  MD Woodchips with an epoxy product No Data
  MA Dense grade gravel Over time the larger (3/4" - 1") stones in the “dense grade gravel" we used tend to rise to the surface resulting in a slightly loose surface that is a bit more difficult for wheels to roll on. We have since found a better material from a different supplier, which is more homogenous and maintains a smooth compact surface. We plan to use this material for future repairs.
SOUTHERN REGION      
  GA Natural/native soils Due to incorrect installation, the trail does not allow water to run off of the trail tread, which creates the need for continuous maintenance.
WESTERN REGION      
  OR Natural/native soil The trail has instances of uneven wear, cracking and washout/runoff annually

Construction practices varied among agencies. Of the thirty‐nine reported trails only eight had surface materials applied solely by contractors. Agency personnel and/or volunteers were utilized in eighteen of the trails and for an additional five trails agency/volunteer personnel in conjunction with contractors applied the surface materials. Application methods also ranged from hand labor only to various forms of compaction methods. Table 12 shows the types of application methods utilized and the personnel who applied the materials.

Table 12.  Application Methods and Personnel
Region Location Surface Material Surface Material Depth Running Slope Application Method/ Application By
ALASKA REGION          
  AK Tek Mix Gravel 0‒4"; 3" minus 5‒8" Up to 5 percent Skid Steer/Compactor by Agency
  AK Natural glacial moraine & Geotextile Fabric Underlay 3/8" minus 6" Up to 5 percent Compaction by Agency
  AK D−1 minus base crushed aggregate; 1/2" minus top dress Moist soil base > 8"; D−1 minus crushed aggregate 1/2" minus (cap) 5‒8" 5 – 8.33% Hand spread & mechanically compacted by Agency
SOUTHWEST REGION          
  TX Cohesive soil and small amounts of gravel Cohesive soil 5‒8" Up to 5 percent Hand tools by Volunteer
MIDWEST REGION          
  KY Natural native soil (cohesive and fissured) No Data No Data No Data
  WI Cohesive and moist soils No Data > 12.5 percent Constructed tread by Agency/Volunteer
  KY Cohesive and moist soils Natural ground surface base; Cohesive and moist soil 5‒8" 8.33 −10.5 percent Cleared path by Agency
  MN Crushed limestone > 8" Up to 5 percent Highway pavement roller by Contractor/Agency
  KY Crushed rock Gravel Base 5‒8"; Cohesive Soil 5‒8" Up to 5 percent No Data by Agency
  IA Crushed Limestone Granular soil base > 8"; Crushed limestone 8.33 −10.5 percent Tractor and hopper by Contractor
  IN Natural native soil No Data No Data No Data
  OH Cohesive soil, dry soil, moist soil No Data > 12.5 percent No Data  Agency/volunteer with contracted trail construction training
  KY Cohesive Soil Cohesive soil > 8:; Gravel 0‒4" 5 – 8.33percent No Data by Agency
  KY Soil with high organic content Cohesive soil 5‒8" 8.33 −10.5 percent Hand labor - digging and raking by Agency/
Volunteer
  KY Dry and granular soils and mulch pine Sand 5‒8"; dry soil 5‒8"; granular soil > 8" > 12.5 percent Hand labor by Agency
  KY Natural native soil No Data 8.33 −10.5 percent No Data
NORTHEAST REGION          
  CT Crushed Rock and stone dust 0‒4" Up to 5 percent Paving box by Contractor/Agency
  MA Existing vegetation and soil Natural Soil 0‒4"; Granular Soil 5‒8" Up to 5 percent No Data by Agency
  VA Klingstone 400 0‒4" Up to 5 percent Compacted and Sprayed by Contractor
  MA 1/2" crusher run Granular Soil 0‒4"; Dry Soil 5‒8"; Cohesive soil > 8" Up to 5 percent No Data by Contractor
  DE Crushed rock and fines No Record 5 - 8.33 percent Spread and compacted by Contractor
  NY Sand, gravel, cinders, crushed brick, wood chips No Record 5 - 8.33 percent Wheel barrow/hand tools by Non-profit trail organization
  VA Crushed rock with Gravel Pave II Gravel Pave II at base; 4" of crushed stone; 2" finely crushed greenstone 5 - 8.33 percent No Data by Agency
  MA Natural/native soil No Record 5 - 8.33 percent No Data
  NE Natural/native soils Cohesive soil > 8" Up to 5 percent Foot and wagon traffic during westward expansion—Natural pioneer trail
  MD Woodchips with an epoxy product 0‒4" Up to 5 percent No Data by Agency
  NE Sand and 1" minus river run aggregate Granular soil base; Sand and 1" minus river run aggregate 0‒4" Up to 5 percent By hand by Contractor/ Youth Conservation Corp
  VA Crusher run gravel and fines Cohesive Soil 5‒8"; Crusher run gravel 4"; 3/8" crusher fines 5 - 8.33 percent Vibratory roller compaction with water spray by Agency
  MA Dense grade gravel Granular Soil 0‒4:; Unknowns 5‒8"; Dense grade gavel Up to 5 percent Bucket spread then rolled by Contractor
SOUTHERN REGION          
  TN Natural/native soil Cohesive Soil 5‒8" 8.33 −10.5 percent High traffic by Volunteers
  GA Natural/native soils Cohesive Soil 5‒8" 5 - 8.33 percent Dingo compaction by Contractor
WESTERN REGION          
  WA Natural soils/sandy loam Granular Soil/Sand > 8" 5 −8.33 percent No Data
  CA Crushed rock Crushed rock 0‒4"; Cohesive Soil 5‒8" 10 – 12,5 percent No Data by Contractor
  UT Crushed rock Crushed rock 5‒8"; Cohesive Soil > 8" Up to 5 percent Compaction by Agency
  NV Decomposed Granite 5‒8" Up to 5 percent 4‒6" thick compacted with steel roller by Contractor
  CA Crushed rock with clay soil fines Crushed rock w/ clay fines  0‒4"; Cohesive Soil 5‒8" Up to 5 percent No Data by Agency
  UT Native soil and crushed limestone No Record > 12.5 percent Trail dozer, hand tools, compactor by Agency
  OR Natural/native soil Moist soils 0‒4"; other soil unknown 5 - 8.33 percent No Data
  NV Natural/native soils and rock Dry soils > 8" 10 – 12,5 percent Hand tools

Some survey respondents provided photographs of the trail and the surrounding environment. Five aggregate trail surfaces were recommended by responding the trail manager and had accompanying photographs. In addition, all the trails have also been designated as accessible trails. While five trails composed of native soil were recommended surfaces, no photographs were available. Photographs of ten of the thirty-nine trails were provided by respondents and can be found in Appendix F.

Summary of Results

The purpose of the trails surface survey was to provide qualified professionals, resource specialists and operations staff of parks and other recreational properties with trails in the United States with descriptive and/or comparative information about the status of construction practices of pedestrian/hiker, natural surface trails. Despite a sixty-one percent survey access rate of survey invitees, the overall completion rate was extremely low. Therefore, the results can be addressed in terms of a general trend in types of surface materials used. The majority of trail surfaces were natural materials that did not use soil stabilizers. However, information on construction practices and maintenance issues was limited in the responses received. A majority of agencies utilized their own personnel or volunteers to apply surface materials or they worked along with contractors. When asked if respondents would recommend the trail surface materials on which they reported, many (48.7%) indicated they would, however accompanying comments received provided limited supporting information for those recommendations.

Recommendations for Further Action

The National Center on Accessibility continues to receive technical assistance inquiries from the field about what types of natural surface materials are available for use on pedestrian trails and how various surface materials perform in different regions of the country. While the intended outcome of the National Trail Surface survey was to establish a database that trail managers could access for trail surface material information and performance data, the data received were disappointedly sparse. The establishment of a national database of trail surface materials used for pedestrian trails, the firmness and stability of those surfaces and how well those surface materials last over time continues to be an identified need for trail managers.

Currently two national resources are available that provide information to trail users on trail locations and trail characteristics. The National Recreation Trail Database hosted by American Trails (http://www.americantrails.org/NRTDatabase/) contains data provided by federal land management agency trail managers. Trail Explorer (www.trailexplorer.com) developed by Beneficial Designs provides trail characteristic information based on data collected and input by trail managers using the Universal Trail Assessment Process (UTAP). Collaboration with one or both providers -- American Trails and Beneficial Designs -- to expand the collected information to include specific natural surface materials used and performance over time on the reported natural pedestrian trails may be an avenue to explore.

[MORE INFO...]

*You must sign in to view [MORE INFO...]