Chapter 19.10
STREETS
Sections:
19.10.020 Street classifications.
19.10.030 Street improvement requirements.
19.10.040 Street design standards table.
19.10.010 Introduction.
A. The items herein contained are the street standards, conditions, and specifications of the city of Rock Island, and are to be considered in conjunction with other provisions of city plans and/or regulations governing the street/circulation system. These are minimums only and may be increased or altered to fit particular situations. The city by this reference adopts the latest edition of the “Standard Specifications for Road, Bridge and Municipal Construction” (hereinafter referred to as the “Standard Specifications”) as prepared by the Washington State Department of Transportation and the Washington State Chapter of the American Public Works Association to govern all aspects of street improvements including but not limited to materials, labor, equipment for installation, workmanship, testing, etc. Any material, design, standard, or testing not specifically addressed within this document shall be as per the Standard Specifications. The city also by this reference adopts the latest version of the “Standard Plans” (engineering drawings hereinafter referred to as the “Standard Plans”) published by the Washington State Department of Transportation.
B. In addition to the specific standards set forth in this chapter, the city may develop a technical specifications guidebook containing drawings that graphically depict the provisions of this chapter and the Standard Specifications. This guidebook may also specify where the city may choose to add to, remove from, and/or replace (in whole or in part) certain aspects of the Standard Specifications and Standard Plans adopted by reference herein. The guidebook is a technical reference document that may be updated periodically based on changes in engineering standards, whether those be city standards or updated standards in the design and construction documents that are adopted by reference in this chapter.
C. These standards and specifications shall apply to any and all work that is done to the city’s street/circulation system, whether required as a condition of development permit approval, right-of-way dig permit, or as a result of an individual request for street construction work. (Ord. 01-062 § 5).
19.10.020 Street classifications.
The following street classification system shall be applied within the city of Rock Island, pursuant to the Rock Island urban area comprehensive plan.
A. Arterial streets are designed to carry a high proportion of the total urban area traffic, and usually serve either traffic going from the central business areas to outlying residential areas, or traffic entering and leaving the urban area. They also provide a connection to collector streets and provide intracommunity continuity while maintaining identifiable neighborhoods.
B. Collector streets are designed to provide access service and traffic circulation within residential neighborhoods and commercial/ industrial areas. They differ from the arterial streets in that they may penetrate residential neighborhoods, distributing traffic from arterials to the ultimate destination or vice versa.
C. Subcollector streets have a primary function of providing access to abutting land and to collector and arterial streets. They offer the lowest level of mobility and through traffic in residential neighborhoods should be deliberately discouraged. (Ord. 01-062 § 5).
19.10.030 Street improvement requirements.
All developments will require improvement of the streets, sidewalks, curbs, gutters, and utilities in full compliance with these development standards.
A. Private Access Streets. The following standards shall apply to the creation of all new lots, and/or upon construction of new residences on existing lots, that are served by a private access street:
1. Every approved private street, as provided for herein, shall connect to an existing public street;
2. The private access street shall be permanently established by plat or easement and shall provide legal access to serve no more than four single-family lots/dwellings;
3. The width of the easement for the private access street shall not be less than 30 feet;
4. The improved surface width of a private access street shall not be less than 20 feet. The improved surface shall consist of three inches of compacted ACP over three inches of compacted five-eighths-inch crushed top course and six inches of compacted one-and-one-quarter-inch base rock. The compacted depths shall meet or exceed existing subgrade depth;
5. The length of a private access street shall not exceed 450 feet, excluding turnaround;
6. Private access streets greater than 150 feet in length shall be improved with an approved turn-around (e.g., cul-de-sac, hammerhead, etc.) for emergency vehicles;
7. Private access streets shall not have a grade that is greater than 12 percent, unless otherwise approved by the city;
8. The turning radius at any intersection of the private access street and a public right-of-way shall not be less than 30 feet;
9. All private access streets shall intersect the public right-of-way at an angle of between 75 and 90 degrees;
10. Private access streets shall have covenants, recorded with the Douglas County auditor’s office, that provide for the following:
a. Unrestricted access shall be provided at all times for emergency and public service vehicles;
b. The maintenance for the private access street is the responsibility of the owners, homeowner’s association or other legal entity; the city of Rock Island shall not maintain private access streets;
c. The utilities located within the private access street are owned by and are the responsibility of the property owners, and shall not be maintained by the city of Rock Island;
11. All utilities that have not already been installed to serve the site shall be constructed within the easement for the private access street to full city standards as set forth herein and installed underground. The list of affected utilities shall include but not be limited to water, sewer, storm drainage, electrical and communications;
12. Private access streets serving more than four residences shall only be allowed as part of a planned development (PD), and shall meet the standards of a public local access street unless a traffic analysis is conducted by the applicant for the PD, and reviewed and approved by the city, that determines the applicability of a lesser standard; and
13. Private access streets shall not be used to serve uses other than specifically provided for by this section, including but not limited to commercial, industrial and/or public uses.
B. Public Street Improvements. The following standards are required for all new public streets:
1. The improvement standards for new development and/or uses for all classifications of public streets shall be as provided for in RIMC 19.10.040.
2. The following minimum standards shall apply to the development of all types of uses including but not limited to single-family, duplex and multifamily residential dwelling units, commercial and industrial activities, and conditional uses for business other than a home occupation, that are proposed to be located on an unimproved right-of-way in an existing plat:
a. The paved surface, curb, gutter, sidewalks, storm drainage facilities and all other utilities shall be installed along the frontage of the property, extending to match the nearest improved street when necessary, and shall meet the requirements of these standards. The plans for said improvements shall be proposed by the applicant’s engineer, with review and approval by the city prior to authorization to construct. (Ord. 01-062 § 5).
19.10.040 Street design standards table.
The following minimum street design standards shall apply within the city of Rock Island.
|
Design Element |
Subcollector |
Collector |
Arterial |
|---|---|---|---|
|
Minimum right-of-way width |
60 feet |
60 feet |
80 feet |
|
Minimum street surface width, curb face to curb face |
30 feet |
36 feet |
40 feet |
|
Curb |
6 inches wide, 6 inches tall above paved surface |
6 inches wide, 6 inches tall above paved surface |
6 inches wide, 6 inches tall above paved surface |
|
Sidewalks: |
|||
|
Residential zones |
5 feet |
5 feet |
5 feet |
|
Commercial and public zones |
5 feet |
5 feet |
5 feet |
|
Industrial zones |
5 feet |
5 feet |
5 feet |
|
Maximum grade in % |
10% |
10% |
10% |
|
Traffic lane width (2) |
10 feet |
10 feet |
12 feet |
|
Parking lane width |
8 feet, one side only |
8 feet, both sides |
8 feet, both sides |
|
Maximum bank slope |
4:1 |
4:1 |
4:1 |
|
Minimum radius on inside face of curb |
50 feet |
100 feet |
100 feet |
|
Cul-de-sac outside radius |
50 |
50 |
50 |
|
Hammerhead, top/sides |
60/20 |
60/20 |
60/20 |
|
Surfacing requirements: |
|||
|
Class B asphalt |
3 inches |
3 inches |
6 inches |
|
Top course |
3 inches |
3 inches |
3 inches |
|
Base course |
6 inches |
6 inches |
6 inches |
Base course depths may require a design depth by a soils engineer if determined by the city engineer.
(Ord. 01-062 § 5).
19.10.050 Design standards.
The design and construction of streets shall be dependent on local site conditions, and the design elements of streets shall conform to the following minimum standards set forth herein:
A. General Requirements.
1. The street layout of every new development shall be in conformance with these standards and with the city’s comprehensive plan. New streets shall provide for the continuation of major streets that serve property contiguous to the development, and shall be designed to provide for the maximum anticipated traffic conditions, as determined by the city.
2. The naming of all streets shall receive approval from the city to assure consistency and elimination of confusing or inconsistent address numbers.
3. Street networks shall provide ready access for fire and other emergency vehicles and the city may require additional access points if such are found to be necessary to protect the public safety.
4. Detailed plans shall be submitted for the city’s review that provide the location and design elements of the proposed street. Computations and other data used for design of the streets shall be submitted to the city for approval.
5. Material and installation specifications shall contain appropriate requirements that have been established by the industry in its technical publications, such as ASTM, WSDOT, WEF, MUTCD and APWA standards.
6. Workmanship and materials shall be in accordance with Sections 1-05 and 1-06 of the current edition of the Standard Specifications.
7. Right-of-way shall include all cut and fill slopes to natural ground.
8. Switch backs, when necessary, shall be designed with a minimum turning radius of 42 feet and a minimum inside radius of 25 feet with pavement widening on the inside edge accordingly.
9. Additional right-of-way width may be required where a clear pattern of future development is present (such as to serve areas included in the urban growth boundary).
10. When needed, average daily traffic (ADT) shall be estimated using the trip generation rates found in the latest edition of Trip Generation Manual by ITE.
11. Individual developments producing ADT exceeding 200, or the accumulation of existing and proposed developments exceeding 500 ADT, may be required, at the discretion of the city, to perform a traffic study completed and stamped by a registered traffic engineer.
12. Any roadway surface that restricts parking shall be so posted at the expense of the developer.
13. Curb radius shall be 30 feet on the inside face of curb on subcollector streets, and 100 feet on collectors and arterials.
14. An approved traffic safety control plan is required when working in the right-of-way.
15. Dust control will be required for all construction projects.
B. Design Elements.
1. The minimum design standards for each street classification are shown in RIMC 19.10.040.
2. The minimum surfacing requirements are described in RIMC 19.10.040. All minimum requirements assume an acceptable, well-drained, stable, compacted subgrade. Additional requirements may be imposed at the discretion of the city if suitable subgrade conditions are not met or if traffic conditions warrant.
3. Street intersections shall be perpendicular or as close to 90 degrees as possible. Where local access streets intersect arterial or collector arterials, intersections shall be designed at grade with the collector or arterial street. Street jogs with offsets of less than 125 feet between centerlines are not allowed.
4. Where city streets connect to state highways, design standards from the most recent edition of the Washington State DOT standards for intersection design shall apply.
5. Cul-de-sacs shall be limited to serve a maximum of 20 lots and shall not exceed 300 feet in length.
6. Traffic control and street name signs shall be provided and installed by the developer in accordance with the current edition of the MUTCD manual, and as directed by the city.
7. Guard rails may be required by the city where deemed appropriate in the interest of public safety, health and welfare. All guard rails shall conform to the criteria in current Washington State Department of Transportation Design Manual as may be amended or revised.
8. At-grade intersection sight distance requirements shall be established for each specific intersection, approach or driveway by utilizing the AASHTO Guidelines in Figures IX-32 through IX-40, pages 739-762 of A Policy on Geometric Design of Highways and Streets, 1990 Edition.
9. All traffic signal modification, traffic control devices, temporary traffic control devices and pavement marking materials shall conform to the Standard Specifications. All marking shall conform to the current MUTCD as adopted by the WSDOT.
C. Driveways, Curbs, Gutters and Sidewalks.
1. Residential driveways giving direct access onto arterials shall be denied if alternate access is available. Commercial driveways may be required to provide joint access to adjoining properties to limit the number of access points onto the arterial.
2. All abandoned driveway areas on the street frontage to be improved shall be removed and new curb, gutter and sidewalk shall be installed.
3. No commercial driveway shall be approved where backing onto the sidewalk or street will occur.
4. Left turns to and from a driveway may be restricted as a condition of development or in the future if such maneuvers are found to be unduly hazardous.
5. All driveways shall be perpendicular or as close to 90 degrees as possible to the public street.
6. The maximum two-way driveway width shall be 20 feet for all residential uses and 30 feet for all other types of uses including but not limited to commercial, industrial and public. A wider driveway for commercial and industrial uses may be approved by the city where a substantial percentage of oversized vehicle traffic exists. In this case the driveway will be sized to accommodate the largest vehicles.
7. The maximum one-way driveway width shall be 10 feet for residential uses and 22 feet for all other types of uses including but not limited to commercial, industrial and public. Parking lot circulation needs shall be met on-site so that the public right-of-way shall not be utilized as part of a one-way parking lot flow.
8. Driveways on local access streets that serve single-family residences may be up to 30 feet in width, subject to approval by the city.
9. The back edge of a driveway shall be at the same elevation as the back of the sidewalk adjacent to the driveway approach. Where there are no sidewalks, the back edge of a driveway shall be at the same elevation as the improved roadway, including any gravel shoulders.
10. No object, including but not limited to fire hydrants, light or power poles, street trees, etc., shall be placed or allowed to remain within 15 feet of a driveway edge.
11. Where a building wall or other design element is permitted to be placed less than 10 feet behind a sidewalk pursuant to the zoning code, both pedestrian and vehicular sight distance shall be maintained.
12. Maximum driveway grade shall be 10 percent.
13. When determined necessary by the city, approach grades and configurations shall accommodate future street widening to prevent major driveway reconstruction.
14. Concrete sidewalks shall be provided as follows:
a. Sidewalks in residential zones shall be a minimum of five feet in width.
b. Sidewalks in commercial and public zones shall be a minimum of five feet in width on both sides of the street.
c. Sidewalks in industrial zones shall be a minimum of five feet in width.
15. Where there are existing sidewalks, the width of any new sidewalk section shall match the existing sidewalk. If the existing sidewalk is narrower than what is required by this chapter, after connecting to the existing sidewalk, the new sidewalk shall be gradually increased to match the width required by this chapter wherever feasible. If the existing sidewalk is wider than what is required by this chapter, the new sidewalk shall maintain the existing sidewalk width for the entire project.
16. Within a planned development, curbside sidewalks may be replaced as a functional equivalent by a separate path or trail with equivalent surface and dimensions, with all weather impervious surfacing on a public easement, when approved as part of the homeowner’s association ownership and responsibility in lieu of public sidewalks as normally placed adjacent to the roadway and serving the same function. Along the perimeter boundary of the PD, the public street and sidewalk improvements shall be in accordance with these provisions.
17. Sidewalks, where necessary because of topographic constraints, may be, upon approval of the city, required on only one side.
18. Sidewalk access ramps shall be included into all pedestrian street crossings and shall meet the requirements of the federal Americans with Disabilities Act.
19. Sidewalk widths are exclusive of the curb width, and shall be measured from the back of the curb to the back of the sidewalk.
20. All sidewalks shall be four-inch thick concrete per the Standard Specifications, with a stiff broom finish. At driveways the concrete shall be six inches thick.
21. Mail boxes shall be placed so the bottom of the mailbox is no less than 44 inches above the street grade, and they shall not be located in such a way so as to obstruct a portion of a sidewalk. The front of a mailbox must be one foot in back of a curb face, outside edge of shoulder or the back of a sidewalk, whichever is applicable. Mailboxes shall be on posts strong enough to give firm support but not to exceed four-inch by four-inch wood or one-and-one-half inch diameter pipe or other material with comparable breakaway characteristics.
22. Concrete curbs six inches wide and six inches high, measured from the finished pavement, shall be constructed in accordance with the Standard Specifications.
23. Sidewalks and curbs shall be included within the dedicated nonpavement right-of-way of all streets.
D. Utilities.
1. Noncity-owned franchise utilities are required to relocate existing facilities at their expense when there is a conflict between their facilities and public street improvements. These facilities are not required to relocate when they are located on a pre-existing utility easement on private property. The improvement work must be a requirement by the city in order for the relocation work to be the financial responsibility of the utility, otherwise all costs shall be the responsibility of the developer.
2. All noncity-owned franchise utility distribution or collection systems including but not limited to power, communications and television shall be placed underground. Where noncity-owned utilities are required to be relocated pursuant to this chapter, they shall be placed underground. Where there are high capacity electrical lines that are feeders passing through an area, an exception may be granted, as agreed to by the city, for requiring those lines to be underground when it is demonstrated that there would be significant system losses, system reliability problems, and substantial costs to the system to underground those lines.
3. Where city and noncity-owned utilities and facilities are proposed to be located and/or relocated outside of a dedicated public right-of-way, easements shall be provided to allow access and maintenance for said utilities and facilities. For city water and sewer utilities, the minimum easement width shall be 15 feet, and may be required to be larger to allow for adequate, safe access for maintenance of the utilities.
4. Trench restoration of a street subsequent to utility placement shall occur either by a patch or overlay method, as required and noted on the right-of-way dig permit provided for within this chapter. When a patch method is used, the trench limits shall be sawcut prior to the final patch.
5. All trench and pavement cuts shall be made by sawcuts. The sawcuts shall be a minimum of two feet outside of the trench width. If the permit requires an overlay, a jack-hammer may be used for the cutting of the existing pavement.
6. All trenching shall be backfilled, compacted and tested in accordance with the Standard Specifications.
7. Temporary restoration of trenches for overnight use is required and shall be accomplished by using MC mix (cold mix) or steel plates.
8. Asphalt Concrete Class B shall be used for restoration of trenching in accordance with the applicable requirements of Section 5-04 of the Standard Specifications. Asphalt patch depths will vary based on the streets being trenched and whether the trenching is parallel or perpendicular to the streets. The actual depths of asphalt shall be shown on the right-of-way permit and the work shall be performed as required by the attached details.
9. All street surfaces, walks or driveways within the street trenching areas affected by the trenching shall be feathered and shimmed to an extent that provides a smooth-riding connection and expeditions drainage flow for the newly paved surface.
10. When trenching within the roadway shoulder(s), the shoulder shall be restored to at least its original condition.
11. The final patch shall be completed as soon as possible and shall be completed within 30 days after first opening the trench. This time frame may be adjusted if delays are due to inclement paving weather, or other adverse conditions that may exist, as determined by the city.
12. Any patch or overlay within the commercial or industrial zoning districts shall be permanent. (Ord. 01-062 § 5).
19.10.060 Plans and profiles.
A plan and profile of the proposed streets showing the following data shall be submitted to the city for approval prior to any final development approval and construction. Map size shall be 24 inches by 36 inches. A one-and-one-half-inch margin shall be provided on the left edge, and a one-half-inch margin shall be provided on the other edges of the map. All maps shall be drawn on mylar sheets.
A. Plan. The plan shall contain the following information:
1. Street alignment in stations of 100-foot intervals;
2. Bearings on street centerline (construction drawings only);
3. Curve data on all horizontal curves, 50-foot stations minimum;
4. Right-of-way lines and width for proposed streets;
5. All topography within the right-of-way limits, including all utilities;
6. Street names for proposed and existing streets;
7. Label all streets and adjoining subdivisions;
8. Typical roadway section of proposed street; and
9. Existing and proposed drainage structures indicating direction of flows.
B. Profile. Profiles shall contain the following information:
1. Original ground line;
2. Stationing in intervals of 100 feet;
3. Control elevation on border of sheet; and
4. Grade line showing grade percents and vertical curves. (Ord. 01-062 § 5).