Exhibit 3 - Design Parameters.pdf

Trail Fundamentals - 49

Design Parameters (FSH 2309.18, Section 23.21, Exhibit 01)

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

Single Lane 8” – 24”

18” – 36” 24” – 48”

Double Lane 48”

48 ” – 60” 60” – 72”

Design Tread Width

Structures (Minimum Width)

36” 48” 48”

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 onsite 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

Design Surface2

Obstacles (Maximum Height)

18” May be common or placed for increased challenge

12” Common and left for increased challenge

3” Uncommon

Target Grade 10% – 25%

5% – 20% 3% – 10%

Short Pitch Maximum

40% 25% 15%

Grade 2

Maximum Pitch Density

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

20% – 40% of trail

15% – 30% of trail 10% – 20% of trail

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

10/16/2008

Trail Fundamentals - 50

MOTORCYCLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Target Cross Slope 5% – 10%

5% – 8% 3% – 5% Design Cross Slope Maximum Cross Slope 15%

10% 10%

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”

Clearing

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 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 trail sustainability.

Trail Fundamentals - 51

Design Parameters (FSH 2309.18, Section 23.22, Exhibit 01)

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.

ALL-TERRAIN VEHICLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Single Lane 48” – 60”

60” 60” – 72”

Double Lane 96”

96” – 108” 96” – 120”

Tread

Structures (Minimum Width)

60” 60” 60”

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 onsite 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

Design Surface2

Obstacles (Maximum Height)

12” May be common or placed for increased challenge

6” May be common and left for increased challenge

3” Uncommon

Target Grade 10% – 25%

5% – 15% 3% – 10%

Short Pitch Maximum

35% 25% 15%

Grade 2

Maximum Pitch Density

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

20% – 40% of trail

15% – 30% of trail

10% – 20% of trail

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

10/16/2008

Trail Fundamentals - 52

ALL-TERRAIN VEHICLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Target Cross Slope 5% – 10%

3% – 8% 3% – 5% Design Cross Slope Maximum Cross Slope 15%

10% 8%

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”

Clearing

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 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.