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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 HIKER/PEDESTRIAN Trail Class 1 Trail Class 2 Trail Class 3 2 Trail Class 4 2 Trail Class 5 2

Wilderness (Single Lane)

0” – 12” 6” – 18” 12” – 24” Exception: may be 36” – 48” at steep side slopes

18” – 24” Exception: may be 36” – 48” at steep side slopes

Not applicable

Non-Wilderness (Single Lane)

0” – 12” 6” – 18” 18” – 36”

24” – 60”

36” – 72”

Non-Wilderness (Double Lane)

36” 36” 36” – 60” 48” – 72” 72” – 120”

Design Tread Width

Structures (Minimum Width)

18” 18” 18” 36” 36”

Type Native, ungraded

May be continuously rough

Native, limited grading rough

Native with some onsite borrow or imported material where needed for stabilization, occasional grading

Intermittently rough

Native with improved sections of borrow or imported material, routine grading

Minor roughness

Likely imported material, Uniform, firm, and stable

Protrusions ≤ 24” Likely common and continuous

≤ 6” May be common and continuous

≤ 3” May be common, not continuous

≤ 3 ” Uncommon, not continuous

No protrusions

Design Surface3

Obstacles (Maximum Height)

24”

14”

10”

8”

No obstacles

Target Grade 5% – 25%

5% – 18% 3% – 12% 2% – 10% 2% – 5%

Short Pitch Maximum

40% 35% 25% 15% 5%

FSTAG: 5% – 12%2

Design Grade 3

Maximum Pitch Density 20% – 40% of trail

20% – 30% of trail

10% – 20% of trail

5% – 20% of trail

0% – 5% of trail

10/16/2008

Designed Use HIKER/PEDESTRIAN Trail Class 1 Trail Class 2 Trail Class 3 2 Trail Class 4 2 Trail Class 5 2

Target Cross Slope Natural side slope

5% – 20% 5% – 10% 3% – 7% 2% – 3% (or crowned)

Design Cross Slope Maximum Cross Slope Natural side slope

25% 15% 10% 3%

Height 6’

6’ – 7’ 7’ – 8’ 8’ – 10’ 8’ – 10’

Width ≥ 24” Some vegetation may encroach into clearing area

24” – 48” Some light vegetation may encroach into clearing area

36” – 60”

48” – 72”

60” – 72”

Design Clearing

Shoulder Clearance 3” – 6”

6” – 12” 12” – 18” 12” – 18” 12” – 24”

Turn

Radius No minimum 2’ – 3’ 3’ – 6’ 4’ – 8’ 6’ – 8’

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

2 Trail Classes 3, 4, and 5, in particular, have the potential to provide accessible passage. If assessing or designing trails for accessibility, refer to the Forest Service

Trail Accessibility Guidelines (FSTAG) for more specific technical provisions and tolerances (FSM 2350).

3 The determination of 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 sustainability of the trail.

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 PACK AND SADDLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Wilderness (Single Lane)

12” – 18” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

18” – 24” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

24” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

Non-Wilderness (Single Lane)

12” – 24” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

18” – 48” 48” – 60” or greater along precipices

24” – 96” 48” – 60” or greater along precipices

Non-Wilderness (Double Lane)

60” 60” – 84” 84” – 120”

Design Tread Width

Structures (Minimum Width)

Other than -bridges: 36” Bridges without handrails: 60” Bridges with handrails:

84” clear width

Other than bridges: 36” Bridges without handrails:

60” Bridges with handrails:

84” clear width

Other than bridges: 36” Bridges without handrails:

60” Bridges with handrails: 84” clear width

Type Native, limited grading

May be frequently rough

Native with some onsite borrow or imported material where needed for stabilization, occasional grading

Intermittently rough

Native, with improved sections of borrow or imported material, routine grading

Minor roughness

Protrusions ≤ 6” May be common and continuous

≤ 3” May be common, not continuous

≤ 3” Uncommon, not continuous

Design Surface2

Obstacles (Maximum Height)

Typically not designed or actively managed for equestrians, although use may be accepted

12”

6” 3”

Typically not designed or actively managed for equestrians, although

PACK AND SADDLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Target Grade 5% – 20%

3% – 12% 2% – 10%

30% 20% 15%

Grade 2

Maximum Pitch Density 15% – 20% of trail

5% – 15% of trail 5% – 10% of trail

Target Cross Slope 5% – 10%

3% – 5% 0% – 5% Design

Slope Maximum Cross Slope 10%

8% 5%

Height 8’ – 10’

10’

10’ – 12’

Width 72” Some light vegetation may encroach into

72” – 96”

96”

Shoulder Clearance 6” – 12” Pack clearance: 36” x 36”

12” – 18” Pack clearance: 36” x 36”

12” – 18” Pack clearance: 36” x 36”

Design

Radius

4’ – 5’

5’ – 8’ 6’ – 10’

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 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 sustainability of the trail.

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 BICYCLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Single Lane 6” – 12”

12” – 24” 18” – 36” 24” – 48” 36” – 60”

Double Lane 36” – 48”

36” – 48” 36” – 48” 48” – 84” 72” – 120”

Tread Width

Structures (Minimum Width)

18” 18” 36” 48” 60”

Type Native, un-graded

May be continuously rough

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

Native, limited grading rough

Sections of soft or unstable tread on grades < 5% may be common material where needed for stabilization, occasional grading

Intermittently rough

Sections of soft or unstable tread on grades < 5% may be present, but not common

Native, routine grading with improved sections of borrow or imported materials

Stable with minor roughness

Likely imported material, Uniform, firm, and stable

Protrusions ≤ 24” Likely common and continuous

≤ 6” May be common and continuous

≤ 3” May be common, not continuous

≤ 3” Uncommon, not continuous

No protrusions

Design Surface2

Obstacles (Maximum Height)

24”

12” 10” 8” No obstacles

Target Grade 5% – 20%

5% – 12% 3% – 10% 2% – 8% 2% – 5%

30% 50% on downhill-only segments

25% 35% on downhill-only segments

15% 10% 8%

Design

Maximum Pitch Density 20% – 30% of trail

10% – 30% of trail 10% – 20% of trail 5% – 10% of trail 0% – 5% of trail

BICYCLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

5% – 8% 3% – 8% 3% – 5% 2% – 3% Design

Slope Maximum Cross Slope 10%

10% 8% 5% 5%

Height 6’

6’ – 8’ 8’ 8’ - 9’ 8’ - 9’

Width 24” – 36” Some vegetation may encroach into clearing area

36” – 48” Some light vegetation may encroach into

Shoulder Clearance 0’ – 12”

6” – 12” 6” – 12” 6” – 18” 12” – 18”

Radius 2’ – 3’

3’ – 6’

4’ – 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 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 sustainability of the trail.

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”

Tread Width

Structures (Minimum Width)

36” 48” 48”

Type Native, limited grading

May be continuously rough

Sections of soft or unstable tread on grades < 5% may be common and continuous material where needed for stabilization, occasional grading

Intermittently rough

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

Native with imported materials for tread stabilization common, routine grading

Minor roughness

Sections of soft tread not common continuous

≤ 3” May be common, not continuous

≤ 3” Uncommon, not continuous

Design Surface2

Obstacles (Maximum Height)

18” May be common or placed for increased challenge

12” Common, left for increased challenge

3” Uncommon

Target Grade 10% – 25%

5% – 20% 3% – 10%

40% 25% 15%

Grade 2

Maximum Pitch Density

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

20% – 40% of trail

15% – 30% of trail 10% – 20% of trail

Typically not designed or actively managed for motorcycles, although

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

5% – 8% 3% – 5% Design

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

48” – 60”

60” - 72”

Shoulder Clearance 6” – 12”

12” – 18” 12” – 24”

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 grades, 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.

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

Single Lane 48” – 60”

60” 60” – 72”

Double Lane 96”

96” – 108” 96” – 120”

Structures (Minimum Width)

60” 60” 60”

Type Native, limited grading

May be continuously rough

Sections of soft or unstable tread on grades < 5% may be common and continuous material where needed for stabilization, occasional grading

Intermittently rough

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

Native with imported materials for tread stabilization common, routine grading

Minor roughness

Sections of soft tread not common continuous

≤ 3” May be common, not continuous

≤ 3” Uncommon, not continuous

Design Surface2

Obstacles (Maximum Height)

12” May be common or placed for increased challenge

6” May be common, left for increased challenge

3”

Target Grade 10% – 25%

5% – 15% 3% – 10%

35% 25% 15%

Grade 2

Maximum Pitch Density

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

20% – 40% of trail

15% – 30% of trail

10% – 20% of trail or actively managed for ATVs, although use may be accepted

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

3% – 8% 3% – 5% Design

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

72” - 96”

Shoulder Clearance 0” – 6”

6” – 12” 12” – 18”

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 grades, 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.

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 FOUR-WHEEL DRIVE VEHICLE > 50" Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Single Lane 72” – 84”

72” – 96” 96” – 120”

Double Lane 16’

16’ 16’

Tread Width

Structures (Minimum Width)

96” 96” 96”

Type Native, 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, occasional grading

Intermittently rough

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

Native with imported materials for tread stabilization common, routine grading

Minor roughness

Sections of soft tread not common

Protrusions ≤ 12” May be common and continuous

≤ 8” May be common and continuous

≤ 4” May be common and continuous

Design Surface2

Obstacles (Maximum Height)

36” May be common or placed for increased challenge

24” Common, left for increased challenge

12”

Target Grade 10% – 21%

5% – 18% 5% – 12%

25% 20% 15%

Grade2

Maximum Pitch Density

Typically not designed or actively managed for 4WD Vehicles > 50”, although use may be

20% – 30% of trail

10% – 20% of trail 5% – 10% of trail or actively managed for 4WD Vehicles > 50”, although use may be

FOUR WHEEL DRIVE VEHICLE > 50" Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Target Cross Slope 8% – 15%

5% – 12% 5% – 8% Design

12% 8%

Height 6’ – 8’

6’ – 8’ 8’ – 10’

Width 72” – 84” Some light vegetation may encroach into

96” - 144”

6” – 12” 12” – 18”

10’ – 15’ 15’ – 20’ 20’ – 30’

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 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 sustainability of the trail.

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.

CROSS-COUNTRY SKI Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Single Lane

2’ – 4’ Typically not groomed

6’ – 8’ (or width of grooming equipment)

8’– 10” (or width of grooming equipment)

Double Lane 6’ – 8’

8’ – 12’ 12’ – 16’

Groomed Width

Structures (Minimum Width)

36” 36” 36”

Type Generally no machine grooming

May receive occasional machine grooming for snow compaction and track setting

Regular machine grooming for snow compaction and track setting

Protrusions No protrusions

No protrusions No protrusions

Grooming and Surface2

Obstacles (Maximum Height)

8”

(no obstacles if machine groomed)

Target Grade 5% – 15%

2% – 10% 0% – 8%

25% 20% 12%

Maximum Pitch Density 10% – 20% of trail

5% – 15% of trail 0% – 10% of trail

Target Cross Slope 0% – 10%

0% – 5% 0% – 5% Design

Slope Maximum Cross Slope

(For up to 50’)

Typically not designed or actively managed for cross-country skiing

20% 15% 10%

Typically not designed or actively managed for cross-country skiing

CROSS-COUNTRY SKI Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Height (Above normal maximum snow level)

8’ (or height of grooming machinery)

8’ – 10’

Width 24” – 60” Light vegetation may encroach into clearing area

72” – 20”’ Light vegetation may encroach into clearing area

96”’ – 168” Widen clearing at turns or if increased sight distance needed

Design

0” - 12” 0” – 24”

8’ – 10’

15’ – 20’ (or to accommodate grooming equipment)

≥ 25’

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 grades, 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.

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

SNOWSHOE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Single Lane 36”

36” – 48” 36’ – 60’

Double Lane 60”

72” 72” – 96”

Tread Width

Structures (Minimum Width)

36” 48” 48”

Type Generally no machine grooming

May receive occasional machine grooming for snow compaction

Likely to receive occasional machine grooming for snow compaction

Surface2

Obstacles (Maximum Height)

12” Uncommon

8” Uncommon (no obstacles if machine groomed)

Target Grade 10% – 20%

5% – 15% 0% – 10%

30% 20% 15%

Maximum Pitch Density 5% – 20% of trail

5% – 25% of trail 0% – 10% of trail

Target Cross Slope 0% – - 10%

0% – 5% 0% – 5% Design

Slope Maximum Cross Slope

Typically not designed or actively managed for snowmobiles.

20%

15% 10% or actively managed for

SNOWSHOE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Height (Above normal maximum snow level)

6’ – 8’ 8’ 8’ – 10’

Width 48” Some light vegetation may encroach into clearing area

72” Light vegetation may encroach into clearing area

72” – 96”

Design

Shoulder Clearance 0”

12” 12” – 24”

3’ – 4’ 3’ – 6’

4’ – 8’ (provide sufficient radius for grooming equipment)

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 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 sustainability of the trail.

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

SNOWMOBILE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Single Lane

4’ – 6’

(or width of grooming equipment) On tight-radius turns, increase groomed width to ≥ 10’

8’ – 10’ (or minimum width of grooming equipment) On tight-radius turns, increase groomed width to ≥ 12’

Double Lane

10’

10’ – 12’

12’ – 20’

Width

Structures (Minimum Width)

6’ 12’ 18’

Type Generally no machine grooming

Commonly rough and bumpy

May receive occasional machine grooming for snow compaction and conditioning

Frequently rough and bumpy

Regular machine grooming for snow compaction and conditioning

Commonly smooth

Surface1

Obstacles (Maximum Height)

6”

(no obstacles if machine groomed)

Target Grade 0% – 12%

0% – 10% 0% – 8%

35% 25% 20%

Grade 2

Maximum Pitch Density

Typically not designed or actively managed for

15% – 30% of trail

10% – 20% of trail 5% – 10% of trail or actively managed for

SNOWMOBILE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Target Cross Slope 0% – 10%

0% – 5% 0% Design

10% 5%

Height (Above normal maximum snow level)

6’

(provide sufficient clearance for grooming equipment)

8’ – 12’ (provide sufficient clearance for grooming equipment)

Width 6’ – 12’ Some light vegetation may encroach into clearing area

8’ – 14’ Light vegetation may encroach into clearing area

10’ – 22’ Widen clearing at turns or if increased sight distance needed

Design

Shoulder Clearance 6” – 12”

12” – 18” 12” – 24”

8’ – 10’ 15’ – 20’ (or sufficient radius for grooming equipment)

25’ – 50’

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

2 The determination of 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 sustainability of the trail.