Chapter 12.01
COUNTY ROADS AND CONSTRUCTION STANDARDS
Sections:
12.01.020 Road classifications.
12.01.050 Approvals and inspections.
12.01.010 Definitions.
As used in this chapter, the following words shall have the following meanings:
A. “Access road” means those roads providing access to abutting land.
B. “Arterial road” means those roads providing a “through movement” of traffic with very little or no direct land access.
C. “Collector road” means those roads providing both services of Access and Arterial approximately equally.
D. “County road” means every public highway as herein defined, or part thereof, outside the limits of incorporated cities and towns and which has not been designated as a primary or secondary state highway.
E. “Cul-de-sac” means the circular area at the terminus of a dead-end road designed for turn-around of motor vehicles.
F. “Design speed” means the safe speed of travel for any particular road considering all design parameters such as sight distance, curve radii and location of intersecting approaches.
G. “Driving surface” means the center portion of the roadway section which has the full design base and top rock in place. When the roadway is surfaced it will generally be from edge of pavement to edge of pavement, except in those areas having paved shoulders.
H. “Private road” means every way or place in private ownership and used for travel of vehicles by the owner or those having express or implied permission from the owner, not by other persons. For the purpose of this chapter, this shall apply only to roadways serving two or more parcels of land.
I. “Right-of-way” means a strip or area of land, granted by deed or easement, for construction and maintenance according to designated use.
J. “Roadbed” means the graded portion of a roadway, upon which the base course, surface course and shoulders are constructed. (Ord. 1981-05 (part))
12.01.020 Road classifications.
The roads within the county system shall be classified, based on their primary functions, into one of the following categories:
A. Arterial road;
B. Access road;
C. Collector road. (Ord. 1981-05 (part))
12.01.030 Design standards.
A. Roadway plans and profile shall be prepared in ink on approved mylar federal-aid sheets with a standard four and one-fourth inches by seven inches Skamania County title block, and shall be signed and sealed by a Washington registered professional engineer. Minimum data on the face of the plan shall in all cases be sufficient to allow a resurvey of the improvement in the future. Design data on all natural factors, such as terrain, rainfall and drainage, shall be provided in support of the proposal.
B. Storm drainage will be designed to protect the roadway against surface and subsurface water, conveying water across, along and away efficiently without damage to roadway or adjacent property.
1. All facilities shall be designed to accommodate, at a minimum, the flow from a twenty-year flood. No cross-roadway culvert shall be less than eighteen inches in diameter.
2. Roadway ditches shall be a minimum of two feet in depth, with side slopes of two to one or flatter.
C. Right-of-way width shall be sixty feet minimum, but in no case less than that required to include all features of the improvement that will require continued county maintenance attention.The entire right-of-way shall be cleared at the time of the construction.
D. Basic roadway design standards are as set out in Table 12.01.030 (Ord. 1981-05 (part))
12.01.040 Construction.
A. Construction of all new public roads shall be accomplished by private parties requesting the roadway creation. Methods of construction and materials used shall conform to those set forth in the current Washington State Department of Transportation Standard Plans and Specifications for Road and Bridge Construction.
B. Washington State laws establish procedures for construction under county administration through rural improvement district methods.
C. Road signing shall conform, both in construction and installation, to the Washington State Department of Transportation Sign Fabrication and Uniform Traffic Control Devices Manuals.
D. Streetlights will be installed at intersecting roads and cul-de-sac areas, the exact locations to be determined by the county engineer. All materials and placement shall be compatible with the existing installations. (Ord. 1981-05 (part))
12.01.050 Approvals and inspections.
A. Approvals and inspections will be required as follows:
1. Design approval before construction work starts;
2. Inspection when the centerline and right-of-way field staking is complete;
3. Inspection when clearing and grubbing is complete;
4. Inspection when drainage structures are complete;
5. Inspection when base rock is in place;
6. Inspection when top rock is in place;
7. Inspection when paving is complete;
8. Inspection when project cleanup and signing is complete;
Important: Work can progress from one stage to the next only upon the approval from the county engineer.
B. County acceptance will take place upon specific action of the board of county commissioners by road resolution. (Ord. 1981-05 (part))
12.01.060 Maintenance.
Maintenance will be assumed by the county upon official acceptance of the completed roadway by the board of county commissioners. (Ord. 1981-05 (part))
12.01.070 Administration.
The county engineer shall provide necessary data and information to the general public to allow compliance. The engineer shall further set forth necessary rules and regulations to assure the intent of the board is carried out. (Ord. 1981-05 (part))
12.01.080 Variances.
A. The minimum design standards for public roads in Skamania County, as set forth in Section 12.01.030, shall apply uniformly to all future applications for public road approvals; provided, that wherever, in the opinion of the board of county commissioners, special circumstances require that the standards must be exceeded or lowered, the commissioners may raise or lower the standards after first setting the matter for public hearing and, if after the public hearing the commissioners find either (1) that the existing standards will not adequately protect the general public and therefore must be raised; or (2) that the application of the existing standards would result in an undue hardship to the applicant or the environment; or (3) that to require the application of the minimal standards would deprive the subject property of rights and privileges given other properties in the area; and, in addition to making one of the above findings the commissioners find that granting the variance will not unduly adversely affect the general public or, with respect to raising standards, that the raising of the standards are necessary for the protection of the general public.
B. Appeal: Any person aggrieved by a decision of the board may appeal said decision pursuant to and in the manner provided by the Washington Administrative Procedures Act. (Ord. 1981-05 (part))
|
ADT |
Access |
|
Collector |
|
Arterial |
|
|---|---|---|---|---|---|---|
|
|
|
|
250 |
|
500 |
|
|
Design Hourly Volume (DHV) |
|
|
|
|
|
|
|
15 years hence |
0—100 |
|
100—200 |
|
200—+ |
|
|
|
Min. |
Desirable |
Min. |
Desirable |
Min. |
Desirable |
|
Design Speed mph |
25 mph |
30 mph |
30 mph |
35 mph |
35 mph |
50 mph |
|
Sharpest Curve Radius in ft. |
150 |
250 |
250 |
350 |
350 |
700 |
|
|
|
Max. |
Max. |
Max. |
|
|
|
Gradient in % |
|
12% |
|
10% |
|
8% |
|
|
Min. |
Desirable |
Min. |
Desirable |
Min. |
Desirable |
|
Pavement Width* |
20 |
22 |
22 |
24 |
24 |
24 |
|
Width of Roadbed |
26 |
30 |
30 |
34 |
34 |
40 |
|
Number of Lanes |
2 |
2 |
2 |
2 |
2 |
2 |
|
|
Min. |
Desirable |
Min. |
Desirable |
Min. |
Desirable |
|
Stopping Sight Distance** |
160 |
240 |
200 |
275 |
240 |
350 |
|
New Bridges Roadway Width |
26 |
|
30 |
|
34 |
|
|
Design Loan (AASHTO) HS 20-44 |
HS 20-44 |
|
HS 20-44 |
|
|
|
|
Vertical Clearance |
16.5 |
|
16.5 |
|
16.5 |
|
|
Right-of-way Width |
60 |
|
60 |
|
60 |
|
|
Structural Design*** |
||||||
|
Base Thickness |
6' |
|
9' |
|
12' |
|
|
Base Type**** |
Crushed |
|
Crushed |
|
Crushed |
|
|
Surfacing Type |
Bitumin. |
|
Bitumin. |
|
ACP |
|
* Driving surface of all new arterial roads must have an asphalt concrete finished surface before acceptance into the county system; provided, that provisions for bonding may be substituted for asphalt surfacing for a period not to exceed eighteen months. All other road classes must have a bituminous surfacing before county acceptance.
** Sight distance shall conform to tables given in Section 322 of the WSDOT Design Manual M22-01 (HR).
*** Structural design procedures shall conform to accepted engineering practices.
**** Basic materials shall conform to the applicable WSDOT Standard Specifications. Maximum rate of grade shall not exceed twelve percent within a three-hundred-foot radius curve, ten percent within a two-hundred-foot-radius curve. For all curves having radius shorter than three hundred feet, maximum rate of grade shall not exceed the above proportional limits.
Curves with a radius of less than five hundred feet shall be widened according to A.A.S.H.O. formulas for widening on curves.
Culs-de-sac: A circular turnaround shall be constructed at the end of every dead-end road. Minimum radius of the facility shall be forty-five feet.