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FOREST SERVICE HANDBOOK
Portland, Oregon
TITLE 7709.56 - ROAD PRECONSTRUCTION HANDBOOK
R-6 Supplement No. 7709.56-94-1
Effective January 26, 1994
POSTING NOTICE. Supplements are numbered consecutively by title and
calendar year. Post by document name. Remove entire document, if one exists, and
replace with this supplement. The last R-6 Supplement to this handbook was
7709.56-93-1.
Document Name
7709.56,4.1
Superseded New
(Number of Sheets)
-
4
Digest:
4.1 - Provides direction to complete a road standard analysis during planning stage
for construction or major reconstruction.
/s/ John E. Lowe
JOHN E. LOWE
Regional Forester
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EFFECTIVE 01/26/94
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CHAPTER 4 - DESIGN
4.1 - Design Criteria. A road standard analysis shall be completed, for all roads,
during planning stage for road construction or major reconstruction. Major
reconstruction involves pavement resurfacing, proposed changes in road
characteristics (widths, alignment, turnouts), or proposed changes to existing
drainage measures. This analysis should focus upon the long term economic,
physical, environmental, and social needs of the road to meet the resource
management objectives. The complexity of the analysis can vary depending on the
purpose and need for the work being proposed, the type or use of the road, and the
magnitude of the work.
The information from this analysis could be made a part of the road management
objectives form, the design warrants, or a separate document if desired. The
signing requirements are the same as signing the road management objectives
form.
All background material used to design a road should be kept in one central file for
current and future reference. This file should also contain a copy of the road
management objectives (FSH 7709.55 chapter 33), field location report (FSH
7709.56 sections 2.27 and 2.28), and project engineering report (FSH 7709.56b
section 1.4).
The following components should be considered in the analysis, and/or covered in
the road management objectives:
1. Environmental and Resource Considerations. These include:
a. Drainage Analysis.
(1) Hydrology computations (design capacity of drainage structure).
(2) Type of drainage structure (bridges, arches, culverts).
(3) Design life of drainage structure (address scour and chemical reaction of
soils).
(4) Fish passage constraint evaluation as needed.
b. Biological Factors.
(1) Fisheries.
(2) Wildlife.
(3) Threatened and endangered species.
c. General Vegetation Management Plan.
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(1) Meets requirements of the Region 6 vegetation management
environmental impact statement.
(2) Considers danger trees outside the clearing limits.
(3) Addresses type of seeding methods, seed type, and application rates.
(4) Addresses use of trees and shrubs where appropriate.
(5) Addresses expected future conditions.
(6) Soil type.
d. Erosion Control Plan.
(1) Culvert spacing and sizing.
(2) Life cycle cost of culverts.
(3) Sediment control techniques.
(4) Drainage control.
(5) Application and type of retaining structures needed.
(6) Erosion susceptibility.
(7) Probability of mass movement.
2. Safety. This includes:
a. Accident history.
b. Road hazard analysis and mitigation measures.
c. Warning signs.
d. Winter driving considerations.
e. Guardrails.
f. Surface texture.
g. Grades.
h. Sight distance.
i. Striping.
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j. Detours.
3. Traffic Requirements. These include:
a. Structural strength of subgrade and surfacing.
b. Season of use.
c. Traffic type.
d. Traffic volume.
e. Traffic control measures that could/should be implemented.
4. Traffic Service Levels. These include:
a. Definitive lengths, widths, and depths of individual road elements (road
widths, shoulders, curve widening, sight distance, and turnout spacing).
b. Design speed.
c. Surface type.
d. Restrictions.
e. Future maintenance level.
5. Vehicle Characteristics. These include:
a. Design vehicle.
b. Critical vehicle.
c. Type of vehicle using road.
6. Road User. This includes:
a. Expectations of recreational user.
b. Implications for mixed traffic.
c. Possibility of non traditional use (bicyclists, pedestrian, or off road
vehicles).
d. Type and amount of traffic.
7. Economics. This includes:
a. Estimated construction cost.
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b. Estimated user cost.
c. Estimated maintenance cost.
d. Benefit/cost ratio.
8. Geotechnical report.
9. Other issues and concerns for the road.
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