(1) 
The county engineer may require the applicant’s engineer to furnish an access plan that will be used by the county to review what impact the proposed access will have on the county road system. Intersection location, spacing, and design are fundamental to the management of access and preservation of capacity provided for in the roadway design. The functional classification of each roadway addresses the appropriate level of access control for that roadway.
(2) 
For proposed access approaches onto any road, the intersections created are classed into two types, roadways and driveways. Roadway intersection design criteria will be used whenever an approach roadway intersects another road, or if traffic signalization is warranted as defined in the current edition of the Manual on Uniform Traffic Control Devices. All roadway intersections, public or private, will use roadway intersection design criteria. Driveway design criteria will be used for residential and commercial driveway approaches as outlined below.
(3) 
When a three or more lane approach is requested, a traffic engineering study along with a signing, striping and traffic channelization plan shall be completed by the applicant’s engineer.
(4) 
The adequacy of all criteria given in this section to the particular situation in question shall be checked by an appropriate engineering analysis. These criteria are minimum guidelines only and may be modified according to traffic volumes and mix, topography, design speed, design vehicle requirements, and other conditions.
(5) 
Access to county roads is regulated through the county approach permit process. No construction of access points or related improvements will be allowed without a valid county approach permit. Permits will be evaluated and issued based on the ability of the proposed access or use to meet these standards.
(6) 
Access to private roads shall be reviewed through the subdivision process. The design of these access points shall follow criteria of AASHTO and other appropriate design guidelines.
(Res. 2008-130 (part), 8/26/08)
Roadway intersection guidelines encourage the preservation of capacity and safe operation of roadways. The following subsections provide the guidelines for roadway intersection location and design.
(1) 
Angles. Proposed roads must intersect one another at ninety-degree angles or as close to ninety degrees as topography permits. If ninety degrees is not possible, the skew angle shall not vary more than fifteen degrees from right angles without the approval of the county engineer.
(2) 
Corner Radii. At road intersections, the following typical ranges of curb line radii are permitted as shown in Table 15.30-7:
Table 15.30-7
Road Classification
Curb Line Radii
Local Road-Local Road Intersection
25 feet
Local Road-Collector Intersection
25 – 30 feet
Collector-Collector Intersection
35 – 45 feet
Industrial/Commercial Intersection
55 – 80 feet
Corner radii greater than the above ranges should be considered if the anticipated composition of traffic warrants such a need.
(3) 
Geometrics.
(A) 
When a new or reconstructed road is designed to intersect with another public road, an intersection plan shall be submitted. The intersection plan must be clearly detailed to show flow line grades and how surface drainage will be controlled at the intersection. Curb return data shall be shown on the road construction plans.
(B) 
At the intersection of different classifications of roads (e.g., a collector with a local access), the centerline slope and typical cross section of the higher classified road should be carried through the intersection with the lower classified road matching in a manner which will not interfere with the smooth movement of traffic in the travel lanes of the higher classified road.
(C) 
Where two roads of the same classification intersect, the centerline grade shall be matched at the center of the intersection with cross slopes varying through the intersection to allow drainage. All classes of local access roads shall be treated as the same classification for purposes of this subsection.
(D) 
Profile grades for all roads (public or private) intersecting onto a county road (existing or proposed) shall be designed and constructed so that adequate entering sight distance is available at the intersection.
(E) 
The design of access points must take into consideration the percentage of truck traffic utilizing the access point. Drainage patterns must also be taken into account in the design of access points. Larger access point radii (typically between forty and fifty feet but possibly as much as seventy feet) may be required for access points when multi-unit vehicles or single-unit vehicles exceeding thirty feet in length (SU vehicle equals thirty feet) comprise ten percent or greater of the traffic expected to use the access point. Vehicles should be able to utilize radius return access points without encroaching on adjacent lanes of traffic.
(F) 
Additional right-of-way in the form of a maintenance easement may be required to ensure the necessary sight distance (“obstruction free zone”) can be preserved. See Standard Plan PW-24.
(Res. 2008-130 (part), 8/26/08)
(1) 
Number of Access Points.
(A) 
Residential lots shall have one access point. Commercial and industrial property shall have one two-way access point or two one-way access points per five hundred feet of total property frontage.
(B) 
Additional access points may be considered by the engineer provided a development or circulation plan is submitted to the engineer indicating that more than the maximum number of access points permitted in this subsection (1) are required to adequately handle access point volumes and will not be detrimental to traffic flow on adjacent roads. For large developments, it is often desirable to consolidate access traffic at a single point, which can be signalized. Proposed signalization must meet appropriate warrants in the MUTCD. Access point signals should be coordinated with adjacent traffic signals and located to provide satisfactory signal progression for through traffic.
(C) 
When property frontages are narrow, such that minimum access point spacing criteria cannot be met, it may be necessary to require joint access locations for adjacent properties at property lines, termed joint usage driveway. The requirements of this section are not intended to override the need for a secondary access for emergency vehicles if such access has been determined by the fire marshal to be necessary under the provisions of the International Fire Code.
(2) 
Vertical Alignment of Access Point. Approach grades and configuration shall accommodate future street widening to prevent major access point reconstruction. The design engineer for proposed developments shall consider the access driveway profile when designing the serving road to ensure that required grade transitions can be complied with considering building setback and lot terrain conditions.
(3) 
Sight Distance.
(A) 
The AASHTO Green Book contains a discussion of the factors and assumptions associated with the calculation of stopping, passing, and intersection sight distance. Stopping sight distance is a vital consideration for both urban and rural situations. Intersection sight distance must be considered in light of the terrain in which the facility is located, and in urban situations to what extent parking is permitted. Where the improvement contemplates some kind of pavement, the simplest approach is to base the design on stopping sight distance (SSD) and intersection entering sight distance (ESD). When analyzing either stopping or entering sight distance for site access, the analysis shall take into account the potential of future sight obstructions constructed at the setback limit of the right-of-way.
(B) 
Stopping sight distance (SSD) shall be used as the acceptance criteria for all driveway accesses. It shall be used for fire apparatus roads emergency vehicle access roads that intersect roads with posted speed limits of less than forty miles per hour as well. The stopping sight distance shall be available throughout all horizontal and vertical curves. Minimum stopping sight distance shall be designed for wet pavement as follows in Table 15.30-8.
(C) 
Values are based on an object height of four and one-quarter feet and a driver’s eye height of three and one-half feet. This is modified from AASHTO for calculation of stopping sight distance for the use of determining acceptable driveways and emergency vehicle access roads only. The effects of grade must be accounted for through the use of a correction factor for grades steeper than three percent as defined by the AASHTO Green Book.
Table 15.30-8
Design Speed (mph)
20
25
30
35
40
45
50
Stopping Sight Distance (feet)
125
155
200
250
305
360
425
(D) 
Entering sight distance (ESD) will be used as the acceptance criteria for all roads that intersect a county or private road within the county with the exception of fire apparatus roads that intersect roads with a posted speed limit of less than forty miles per hour. The entering sight distance must be equal to or exceed the required entering sight distance listed below in Table 15.30-9 for the legal posted speed limit. Sufficient entering sight distance in each direction along a road must be provided to permit vehicles to safely enter the roadway. Entering sight distance for all movements shall be designed for the posted speed of the facility being entered as follows, unless unusual design or safety considerations warrant increased sight distance requirements as determined by the county engineer.
(E) 
The effects of grade must be accounted for through the use of a correction factor for grades steeper than three percent as defined by the AASHTO Green Book.
(F) 
Values are based on driver’s eye height of three and one-half feet set back at least fourteen and one-half feet from the edge of traveled way and an object height of four and one-quarter feet.
Table 15.30-9
Posted Speed (mph)
Minimum Entering Sight Distance (ft)
25
30
35
40
45
50
ESD Turning Right
240
290
335
385
430
480
ESD Turning Left
280
335
390
445
500
555
Commercial Access
295
355
415
470
530
785
(G) 
At any intersection of a private road access point with a county road, there must be a sight distance triangle which provides an unobstructed line of sight from a point fourteen and one-half feet behind the edge of the traveled way to a point in the traveled way at least equal to the required entering sign distance (see Standard Plan PW-24). Additional right-of-way in the form of a maintenance easement may be required to ensure the necessary sight distance (“obstruction free zone”) can be preserved.
(H) 
In situations where the entering sight distance is questionable, the county engineer may require the applicant’s engineer to prepare an entering sight distance diagram, together with appropriate field measurements, and submit them for review prior to the approval of the construction plans. The diagram and measurements shall be stamped and signed by the applicant’s engineer.
(I) 
Exiting sight distance for vehicles on the major road to view an oncoming vehicle traveling at the speed limit and turn safely onto a minor road or driveway shall be made available. Design analysis should be similar to that used for entering sight distance.
(J) 
For commercial/industrial driveways with heavy traffic volumes of significant numbers of trucks on collector streets, the county engineer may require a transportation impact study to determine access design. Notwithstanding any other provisions, driveways will not be allowed where they are prohibited by separate county commission action or where they are determined by the county engineer to create a hazard or impede the operation of traffic on the roadway. Access to commercial or industrial use corner lots shall be located on the lower volume roadway and as close as practicable to the property line most distant from the intersection.
(K) 
Driveway design needs to address the type of vehicle composition anticipated, traffic volume and land use activities being accessed. Driveway placement needs to be carefully determined to minimize interference with normal roadway operation. Driveways need to be constructed where entering sight distance in conjunction with driveway access would be adequate for safe traffic operations. Closely spaced driveways are discouraged.
(L) 
Passing sight distance shall be provided for where determined by the county engineer.
(Res. 2008-130 (part), 8/26/08)
(1) 
Driveway approaches are broken into three general classifications, residential driveway approach, commercial driveway approach and temporary construction approach. Commonly overlooked design issues include inadequate radii at the intersection with the roadway, excessive approach grades and grade changes within the driveway approach area, consideration of water runoff, inadequate width, and inadequate entering sight distance. Existing driveways may be reconstructed to meet current county standards. No person, party, firm, corporation, or entity shall construct, or alter any approach from any abutting property to any county road located in unincorporated Chelan County, permanently or on a temporary basis, without first obtaining or having an approach permit from the department of public works. A copy of each driveway approach permit shall be available for inspection at the site during the life of the permit.
(2) 
A residential driveway approach is used to serve two single-family residences (primary or accessory residences). Driveways serving as access to more than two single-family residences (primary or accessory) will be considered a shared residential driveway.
(3) 
A shared residential driveway will be the minimum standard road used to serve three or four residences. The shared residential driveway standard shall be used on the common shared portion of a driveway. No more than four residences are served unless the road is upgraded to an emergency vehicle access road (EVAR). All shared residential driveways shall meet the following criteria:
(A) 
The shared residential driveway will lie within a minimum twenty-foot easement. The full width of the easement will be clear of sight obstructions to a height of thirteen feet, six inches.
(B) 
The minimum width of the improved driving surface shall be twelve feet.
(C) 
The minimum surfacing shall be six inches of compacted crushed surfacing (either CSBC or CSTC) on a suitable subgrade.
(D) 
The maximum grade shall be twelve percent.
(E) 
Approved turnaround features will be constructed at the termination or within one hundred and fifty feet of the termination of any shared residential driveway. Where a shared residential driveway exceeds one thousand feet in length, pull out and turnaround features will be provided as follows:
(i) 
Pull out features will be constructed to a minimum of eighteen feet of total width (lane plus widening) and a minimum fifty feet in length, and will have no more than five hundred feet separation.
(ii) 
Turnaround features will be constructed with maximum of one thousand feet separation. Turn-around design will be based upon Standard Plan PW-23-A or PW-23-B except that the easement width shall be twenty feet minimum.
Address signs shall be installed at the intersection of any residential shared driveway and a county road. Additionally, address signs will be placed at any intersection that follows along the shared residential driveway. No parking shall be permitted on a shared residential driveway. The shared residential driveway shall be appropriately signed with “No Parking Fire Lane” signs placed along driveway and at locations of pull out or turnaround features.
All shared residential driveways shall have a maintenance agreement recorded with the final plat approval that specifies consistent maintenance in accordance with the approved plat/plans. Further, the “No Parking Fire Lane” shall be strictly enforced.
(4) 
Rural and urban residential, joint usage and shared residential driveway approaches shall be constructed at the maximum practical distance, but in no event (unless a closer distance is permitted in more intense land uses such as approved LAMIRDs or in UGAs) less than one hundred twenty-five feet from a state highway, county collector, or local access intersection; or less than seventy-five feet from a local access class 3 cul-de-sac intersection. Such driveway approaches shall not be spaced closer than seventy feet (unless a closer distance is permitted in more intense land uses such as approved LAMIRDs or in UGAs), measured centerline to centerline, from another driveway approach. See Standard Plan PW-25 for details.
(5) 
Accesses serving from five to twelve lots shall meet emergency vehicle access road standards.
(6) 
A commercial approach is used for multifamily and commercial uses with approach traffic volumes of more than forty or more vehicle trips per day. When multi-access points are desired to serve one site then each driveway approach shall conform to the applicable use criteria. See Standard Plan P-26 for details.
(7) 
A temporary construction approach is used for access to a county road from a construction site. Commercial approach design criteria shall be used with the addition of measures for preventing mud and construction debris from being deposited on the county road. See Standard Plan P-27 for details.
(Res. 2008-130 (part), 8/26/08)
Traffic calming measures may be utilized in Chelan County. They are especially encouraged where traffic calming is desired or innovative solutions are necessary to solve specific design issues.
Design will be consistent with WSDOT design standards and criteria.
(Res. 2008-130 (part), 8/26/08)
(1) 
Driveways (Access Points).
(A) 
The outer edge of a driveway approach shall not be constructed closer than seventy feet to a bridge, or other structure that may warrant end protection using guard-railing in accordance with the most current criteria adopted by the Washington State Department of Transportation.
(B) 
All commercial driveway approaches shall be paved to the end of the thirty-five-foot radius, with a minimum of two inches compacted depth of hot mix asphalt over two inches compacted depth crushed surfacing top course.
(C) 
The minimum distance between the paved edge of a driveway approach and the face of an obstruction, including existing utility appurtenances which may cause a traffic safety concern, may be no less than four feet without curbing and three feet with curbing on the approach. Obstructions located closer than these distances which may cause a traffic safety concern must be relocated.
(D) 
The construction of all access points involving removal of existing vertical curb or vertical curb and gutter shall conform to this section. When cutting through or crossing vertical curb, gutter and sidewalk, access approaches must extend from the curb to back of sidewalk and be of portland cement concrete. When an opening for an access or for any other purpose is to be constructed through an existing portland cement concrete vertical curb, the existing curb, or curb and gutter, shall be saw cut at the limits of work or removed to the nearest construction joint and the opening replaced with standard curb and driveway. Existing street trees, streetlights, traffic signal facilities, utility poles, and fire hydrants must be shown on any plan for access point construction in an area of existing vertical curb. Prior to commencing any necessary removal or relocation of any public utilities, structures, trees, or plantings due to construction of an access point, the applicant must secure approval from the person or persons having ownership or control of such facilities or features.
(E) 
Standard drawings are required for residential driveway approaches and commercial driveway approaches. Driveway approaches shall be designed so as to provide adequate entering sight distance in both directions on the roadway being accessed, and so as not to interfere with drainage.
(F) 
Whenever a potential feasible access exists to any property from two or more roads, the county engineer may refuse access to the higher classified road. Wherever a potential feasible access exists to any property from a public road and private easement, the county engineer may refuse access to the public road.
(G) 
New access locations internal to the platting of property shall be unified whenever possible to create the fewest number of access points onto a road if they access roads of a classification higher than a local access class 3. If required by public works for review before any public hearing, the applicant’s engineer shall submit a lot access plan that demonstrates how all lots and any existing driveway easements will be constructed and that they will meet county road approach standards. Plan shall include a plan view, vertical profile, provisions for stormwater drainage, and grading limits as required. A county standard driveway approach may be required to be provided to each lot according to the lot access plan during construction of the roadway subgrade. The lot access plan shall be submitted and approved prior to any bond submittal and final plat recording.
(H) 
Lots of record in existing formal plat subdivisions, short plats and large lots not served by a minor or major driveway shall be permitted a minimum of one residential driveway or joint usage driveway or shared residential driveway.
(I) 
Access to corner lots should be from the lesser-classified road and at the greatest distance possible from the intersection. The number of intersections should be minimized as much as possible, particularly as classification of the affected roads increases. Intersection spacing should be maximized wherever possible.
(2) 
Intersections.
(A) 
Roadway intersections, public or private, shall be designed so as to provide adequate entering sight distance in both directions on the roadway being accessed, and so as not to interfere with drainage. For roadway intersections, the following general design criteria shall apply:
(i) 
Intersections should not be located on or near sharp curves, i.e., curves with radii close to the AASHTO Green Book minimums. Intersections should be located sufficient distance from all curves to provide proper sight distance for vehicles on the intersecting road or driveway and on the through road.
(ii) 
Multi-leg intersections (i.e., those with more than three legs) are not permitted within local road networks. In local road networks “T” and “L” intersections only are encouraged. For collector access, four-leg intersections are encouraged.
(B) 
The intersection of two local roads should be designed to operate with the appropriate traffic control device (e.g., stop or yield signs) whenever possible. Intersections within the subdivision should be of the “T” type; for lower speed facilities of minor or cul-de-sac classification, “L” type intersections are acceptable. Four-legged intersections within the subdivision must receive the approval of the county engineer.
(C) 
Notwithstanding the requirements of this section, the number and location of intersections may be more restrictive than described herein if deemed necessary by the county engineer. The county engineer shall base the determination on existing and projected traffic volumes and channelization and signalization on the existing county road, traffic, and turning movements generated by the existing and/or proposed project(s), and other applicable traffic design criteria as well as other driveways in the vicinity of the proposed access approach, the amount of lot frontage along the road, and channelization/traffic control.
(Res. 2008-130 (part), 8/26/08)