Handbook_Excerpt_06172016.pdf

WO AMENDMENT 2309.18-2008-4

EFFECTIVE DATE: 10/16/2008

DURATION: This amendment is effective until superseded or removed.

2309.18_20

FSH 2309.18 - TRAILS MANAGEMENT HANDBOOK

CHAPTER 20 - TRAIL DEVELOPMENT

23.2 - Standard Terra Trails - Motorized

23.21 - Motorcycle Design Parameters

The next page displays the Motorcycle Design Parameters, followed by considerations regarding their application.

Application considerations for Motorcycle Design Parameters:

1. NFS trails that allow motorcycle use must be designated for that vehicle class pursuant to 36 CFR 212.51 and displayed on a motor vehicle use map (FSM 7703.1).

2. For NFS trails that have been designated for motorcycle use and that have a Designed Use of Motorcycle, apply the Motorcycle Design Parameters and the following guidance.

a. A variety of distances and recreation experiences may be provided by designing cutoffs for less experienced riders within a system of loop trails. An experienced rider can ride approximately 50 miles in an average day. Some riders can cover over 100 miles in a day.

b. Trail alignment should exhibit decreasing randomness between Trail Class 2 and Trail Class 4.

c. Favor drainage dips over water bars.

d. On trails in Trail Class 4, the alignment is generally moderate, with no sharp curves combined with steep grades. Novice riders may be subjected to sharp curves, but generally not in combination with rough surfaces or steep grades (see sec. 23.21,

ex. 01).

e. Favor climbing turns over switchbacks, within the applicable Design Parameter grade tolerances, as deemed appropriate, considering the use and direction of travel.

Modify the level of challenge of a curve by increasing or decreasing its turning radius.

f. For trails in Trail Class 4, locate turns on level ground or on slopes of less than 6 percent. On trails designed for novice and intermediate riders, consider providing a 4-to-6-foot barrier on the downhill side of a switchback.

g. The speed of a motorcycle entering a turn varies depending on the radius of the turn. A trail designer can slow the speed of a motorcycle entering a turn by

DURATION: This amendment is effective until superseded or removed.

decreasing its turning radius. A trail designer may increase the length of a trail in a limited area by increasing the number of turns.

h. Hardening of switchbacks and climbing turns in sensitive soils is recommended.

Suggested hardening materials include concrete blocks, soil, and cement.

i. For minimum bridge widths and railing heights, refer to FSH 7709.56b, section 7.69, exhibit 01, Trail Bridge Design Criteria. Bridges should have a straight approach and should not change directions. Special decking may be necessary to accommodate wheeled vehicles.

j. To minimize confusion, consider locating trail junctions so that no more than two trails intersect at one point.

DURATION: This amendment is effective until superseded or removed.

23.21 – Exhibit 01

MOTORCYCLE DESIGN PARAMETERS

Design Parameters are technical guidelines for the survey, design, construction, maintenance, and assessment of National Forest System trails, based on their Designed Use and Trail Class and consistent with their management intent1. Local deviations from any Design Parameter may be established based on trail-specific conditions, topography, or other factors, provided that the deviations are consistent with the general intent of the applicable Trail Class.

Designed Use MOTORCYCLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5 Design Tread Width

Single Lane Typically not designed or actively managed for motorcycles, although use may be allowed

8” – 24”

18” – 36” 24” – 48” Typically not designed motorcycles, although use may be allowed Double Lane 48”

48 ” – 60” 60” – 72”

Structures (Minimum Width)

36” 48” 48”

Design Surface2

Type Native, with limited grading

May be continuously rough

Sections of soft or unstable tread on grades < 5% may be common and continuous

Native, with some on-site borrow or imported material where needed for stabilization and occasional grading

Intermittently rough

Sections of soft or unstable tread on grades < 5% may be present

Native, with imported materials for tread stabilization likely and routine grading

Minor roughness

Sections of soft tread not common

Protrusions ≤ 6” May be common and continuous

≤ 3” May be common, but not continuous

≤ 3” Uncommon and not continuous

Obstacles (Maximum Height)

18” May be common or placed for increased challenge

12” Common and left for increased challenge

3” Uncommon

DURATION: This amendment is effective until superseded or removed.

23.21 – Exhibit 01--Continued

Designed Use MOTORCYCLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5 Design Grade 2

Target Grade 10% – 25%

5% – 20% 3% – 10%

Short Pitch Maximum

40% 25% 15%

Maximum Pitch Density 20% – 40% of trail

15% – 30% of trail 10% – 20% of trail

Design Cross Slope

Target Cross Slope 5% – 10%

5% – 8% 3% – 5%

Maximum Cross Slope 15%

10% 10%

Clearing

Height 6’ – 7’

6’ - 8’ 8’ - 10’

(On steep side hills, increase clearing on uphill side by 6” – 12”)

36” – 48” Some light vegetation may encroach into clearing area

48” – 60”

60” - 72”

Shoulder Clearance 6” – 12”

12” – 18” 12” – 24”

Turn

Radius 3’ – 4’

4’ – 6’ 5’ – 8’

1 For definitions of Design Parameter attributes (e.g., Design Tread Width and Short Pitch Maximum), see FSH 2309.18, section 05.

2 The determination of the trail-specific Design Grades, Design Surface, and other Design Parameters should be based upon soils, hydrological conditions, use levels, erosion potential, and other factors contributing to surface stability and overall trail sustainability.

DURATION: This amendment is effective until superseded or removed.

FSH 2309.18 – TRAILS MANAGEMENT HANDBOOK

CHAPTER 20 – TRAIL DEVELOPMENT

23.22 - All-Terrain Vehicle (ATV) Design Parameters

The next page displays the All-Terrain Vehicle (ATV) Design Parameters, followed by considerations regarding their application.

Application considerations for All-Terrain Vehicle Design Parameters:

1. NFS trails that allow ATV use must be designated for that vehicle class pursuant to 36 CFR 212.51 and displayed on a motor vehicle use map (FSM 7703.1).

2. For NFS trails designated for ATV use and that have a Designed Use of ATV, apply the ATV Design Parameters and the following guidance.

a. A variety of distances and recreation experiences may be provided by designing cutoffs for less experienced riders within a system of loop trails.

b. Trail alignment should exhibit decreasing randomness between Trail Class 2 and Trail Class 4.

c. Include frequent elevation changes and turns appropriate for each skill level.

These design features can be incorporated as appropriate to slow vehicle speeds, increase safety, and provide more riding time per mile (see sec. 23.22, ex. 01).

d. Favor drainage dips over water bars.

e. Favor climbing turns over switchbacks, within the applicable Design Parameter grade tolerances, as deemed appropriate, considering the use and direction of travel..

Modify the level of challenge of a curve by increasing or decreasing its turning radius.

f. On trails in Trail Class 4, the alignment generally should be moderate, with no sharp curves combined with steep grades. Novice riders may be subjected to sharp curves, but generally not in combination with rough surfaces or steep grades. If possible, incorporate climbing turns with a wide radius for ascending hills. Use switchbacks on steep slopes only for more challenging trails.

g. Hardening of switchbacks and climbing turns in areas with sensitive soils is recommended. Suggested hardening materials include concrete blocks, soil, and cement.

DURATION: This amendment is effective until superseded or removed.

FSH 2309.18 – TRAILS MANAGEMENT HANDBOOK

CHAPTER 20 – TRAIL DEVELOPMENT

h. For minimum bridge widths and railing heights, refer to FSH 7709.56b, section 7.69, exhibit 01, Trail Bridge Design Criteria. Bridges should have a straight approach and should not change directions. Special decking may be necessary to accommodate wheeled vehicles.

i. To minimize confusion, consider locating trail junctions so that no more than two trails intersect at one point.

DURATION: This amendment is effective until superseded or removed.

23.22 – Exhibit 01

ALL-TERRAIN VEHICLE DESIGN PARAMETERS

Design Parameters are technical guidelines for the survey, design, construction, maintenance, and assessment of National Forest System trails, based on their Designed Use and Trail Class and consistent with their management intent1. Local deviations from any Design Parameter may be established based on trail-specific conditions, topography, or other factors, provided that the deviations are consistent with the general intent of the applicable Trail Class.

Designed Use ALL-TERRAIN VEHICLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5 Design Tread

Single Lane Typically not designed or actively managed for ATVs, although use may be allowed

48” – 60”

60” 60” – 72” Typically not designed

ATVs, although use may be allowed Double Lane 96”

96” – 108” 96” – 120”

Structures (Minimum Width)

60” 60” 60”

Design Surface2

Type Native, with limited grading

May be continuously rough

Sections of soft or unstable tread on grades < 5% may be common and continuous

Native, with some on-site borrow or imported material where needed for stabilization and occasional grading

Intermittently rough

Sections of soft or unstable tread on grades < 5% may be present

Native, with imported materials for tread stabilization likely and routine grading

Minor roughness

Sections of soft tread uncommon

Protrusions ≤ 6” May be common and continuous

≤ 3” May be common, but not continuous

≤ 3” Uncommon and not continuous

Obstacles (Maximum Height)

12” May be common or placed for increased challenge

6” May be common and left for increased challenge

3” Uncommon

DURATION: This amendment is effective until superseded or removed.

23.22 – Exhibit 01--Continued

Designed Use ALL-TERRAIN VEHICLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5 Design Grade 2

Target Grade 10% – 25%

5% – 15% 3% – 10%

Short Pitch Maximum

35% 25% 15%

Maximum Pitch Density 20% – 40% of trail

15% – 30% of trail

10% – 20% of trail

Cross Slope

Target Cross Slope 5% – 10%

3% – 8% 3% – 5%

Maximum Cross Slope 15%

10% 8%

Clearing

Height 6’ – 7’

6’ – 8’ 8’ – 10’

(On steep side hills, increase clearing on uphill side by 6” – 12”)

60” Some light vegetation may encroach into clearing area

60” – 72”

72” - 96”

Shoulder Clearance 0” – 6”

6” – 12” 12” – 18”

Turn

Radius

6’ – 8’ 8’ – 10’ 8’ – 12’

1 For definitions of Design Parameter attributes (e.g., Design Tread Width and Short Pitch Maximum), see FSH 2309.18, section 05.

2 The determination of the trail-specific Design Grade, Design Surface, and other Design Parameters should be based upon soils, hydrological conditions, use levels, erosion potential, and other factors contributing to surface stability and overall sustainability of the trail.

DURATION: This amendment is effective until superseded or removed.