Transportation Engineering

The design of public and private roadways shall be largely based upon these Standards, the manuals and standards of Section 115 and the Standard Drawings.

The County reserves the right to restrict specific combinations of horizontal and\or vertical alignments which contain steep grades, minimum K values, minimum centerline radii, and broken back curves.

250.1 General

250.1.1 Roadway Cross Section

1. Standard Drawings C110 to C140 are to be used for the design of roadways under the jurisdiction of the County.  These figures illustrate the required right-of-way width, paved widths, shoulder widths, lane configurations, easement widths, pedestrian facility widths, planter strips widths, curbs, bike facility widths, and design speeds for each functional classification.
2. Roadway cross sections shall consider the Regional Street Design Type Guidelines as described per Comprehensive Plan Chapter 5 as illustrated Map V-5.
3. Community and Design Plans are provided in the Comprehensive Plan that have exceptions to these Standards.
4. The Active Transportation Plan, projects adopted in the Comprehensive Plan and CIP should be referenced in determining the appropriate bicycle facility.
5. An urban street section shall be used on all roadways within the Urban Growth Boundary (UGB) and within unincorporated communities except as allowed by Engineering.
6. A rural road section shall be used on all roadways outside the UGB, unless located within an unincorporated community.

250.1.2 Design Speed

1. The design speed for all roads shall be determined by Engineering.
2. The minimum design speed for all public roads shall be 25 MPH.
3. Design speed shall be determined or assumed as one of the following:
4. Intended posted regulatory speed.
5. Existing posted regulatory speed.
6. 85th percentile speed.
7. In the vicinity of a horizontal curve, the advisory speed posting plus 10 MPH.

250.1.3 Design & Control Vehicle

1. Engineering shall determine the appropriate design and control vehicle for a facility. 
2. A "design vehicle" frequently uses a facility and must be accommodated without encroaching into opposing traffic lanes.
3. A "control vehicle" infrequently uses a facility but encroachment into opposing traffic lanes, multiple-point turns or minor encroachment into the roadside is acceptable. 
4. The Engineer may be required to provide evidence that the design vehicle and control vehicle are accommodated in their designs.
5. Functional classification, safety and roadway use all play a role in determining the acceptability of lane encroachment by control vehicles.  For example, on a local road, full lane encroachment by a control vehicle may be acceptable if sight distance was adequate while on a major arterial, such encroachment may not be permitted. 

250.2 Curbs

1. When needed, curbs shall conform to Standard Drawings S100 to S180, as specified by Engineering.  
2. Curbs may be omitted when it is demonstrated that surface water quality and storm water discharge considerations can be better achieved by collection in shallow, grass-lined swales paralleling the roadway and provisions for maintenance can be arranged.  Additional pavement width along shoulders or on separated facilities shall be shown to demonstrate sufficient accommodations for pedestrian and bicycle traffic.  
    

250.3 Pedestrian Improvements - General

1. All pedestrian improvements shall comply with the PROWAG standards for a pedestrian access route. The specific provisions of the PROWAG standards for pedestrian access routes can be found in the Sidewalk/Multiuse Path – ADA Design Review Checklist.
2. Pedestrian facilities are required within the UGB and unincorporated communities.  Pedestrian facilities are not required outside the UGB except within unincorporated communities.
3. If right-of-way or public easement is adequate and a development is required to construct a pedestrian facility, the development is required to connect to an existing pedestrian facility that is terminated mid-block and within 15 feet of the proposed pedestrian facility, the development shall connect to that pedestrian facility.  The development shall be required to construct the connecting pedestrian facility and associated improvements including curb, drainage and landscaping and comply with Section 250.3.9. 
4. On roadways with an anticipated ADT of less than 400 where pedestrian facilities would otherwise be required, pedestrian facilities may be provided on only one side. 
5. Minimum pedestrian facility widths are found in ZDO Section 1007.  However, compliance with Section 250.1.1 is required. 
6. Pedestrian facilities within the public right-of-way may have a running slope in the direction of pedestrian travel equal to the grade of the adjacent roadway. Pedestrian facilities outside the public right-of-way may not have a running slope in the direction of pedestrian travel in excess of 5%.

250.3.1 Sidewalks

Sidewalks should be designed to comply with Standard Drawing S960.

250.3.2 Shared-Use (Multi-Use) Paths

1. As an alternative or in addition to sidewalk and separated bike facilities, shared use paths may be allowed  according to the criteria of the ZDO and as part of conditions of approval of development or allowed as part of a County initiated project.
2. The location of planned shared use paths is provided by Map 5-3 of the Comprehensive Plan.
3. The required shared use path width varies from an unobstructed minimum width of ten feet depending upon anticipated use.  These circumstances will consider relative anticipated use of the facility, topography, preservation of significant trees, safety, and right-of-way.
4. Shared use paths under County jurisdiction shall be constructed of concrete.

250.3.3 Cycle Tracks

Separated pedestrian facilities constructed at the same grade as a cycle track shall be physically or visually separated from the cycle track.  The design of these facilities should be based upon Standard Drawing S960.

250.3.4 Landscape Strips

1. All pedestrian facilities should be located adjacent to a landscape strip or other physical buffer from vehicular traffic unless otherwise approved. 
2. Landscape strip width shall be determined per Standard Drawings C110-140 or by the Comprehensive Plan.
3. Landscape strips shall include landscaping elements of Section 255. 

250.3.5 Right-of-way and Easements

All roadway improvements including sidewalks, cycle tracks, and shared use paths should be constructed within the public right-of-way.  These improvements may be located within a public easement if approved.

250.3.6 Horizontal and Vertical Clearance

A minimum horizontal clearance around any obstacles shall be compliant with PROWAG and be provided on all pedestrian facilities.

The minimum vertical clearance above a sidewalk or shared use path is eight feet.

250.3.7 Pedestrian Facilities Cross Slope

The cross slopes of pedestrian facilities perpendicular to the direction of travel shall be designed to a maximum 1.5%, and shall not exceed 2% per ADA requirements as identified in the Sidewalk/Multiuse Path – ADA Design Review Checklist.

250.3.8 Curb Ramps

At any location where the route of pedestrian travel requires crossing a curb, a curb ramp shall be provided. Two curb ramps are typically required at each intersection corner, with one curb ramp to serve each direction of pedestrian travel.  Curb ramp considerations include:

1. Curb ramps are to be placed as near as possible to continue the natural path of pedestrians using the adjacent sidewalk.
2. Design of curb ramps shall comply with ADA requirements as identified in the Curb Ramp – ADA Design Review Checklist. Typical curb ramp designs are shown on Oregon Standard Drawings RD755, RD756 and RD757. Typical designs for a ramp to allow pedestrians to transition from the end of a sidewalk, separated path or shared use path to the road surface are shown on Oregon Standard Drawing RD754.
3. For pedestrian facilities proposed to end mid-block that do not connect to an existing pedestrian facility, curb ramps shall be provided as such:
   1. At both ends of the new pedestrian facility when the proposed construction length exceeds 100 feet. 
   2. At one end of the new pedestrian facility when the proposed construction length is between 50 feet and 100 feet.
   3. No curb ramps if not required by 1) or 2).
4. For pedestrian facilities proposed to end mid-block that connect to an existing pedestrian facility, curb ramps shall be provided as such:
5. At the end of the new pedestrian facility when a curb ramp already exists.  The existing curb ramp, even if located off-site from a development, shall be removed and replaced with appropriate curb and landscaping. 
6. At the end of a new pedestrian facility when the proposed construction length exceeds 50 feet. 
7. No curb ramps if not required by 1) or 2).
8. Exceptions to the ADA requirements for curb ramps may be requested using the process identified in Section 170 in cases of physical barriers that make full compliance infeasible.

250.3.9 Curb Ramp Closures

1. A crosswalk may be considered for closure and a curb ramp not required under any of the following criteria:
2. There is no sidewalk or shoulder at least five feet wide on the opposite side of the street on the natural path of pedestrian travel and the construction of the curb ramp would result in a safety issue;
3. Per the provisions of ORS 801.220 there is a marked crosswalk at the intersection serving the same direction of pedestrian travel and the construction of the curb ramp may result in a safety issue.
4. There are closely spaced crossings of offset T-intersections;
5. The crosswalk is within a maneuvering area or storage length of an intersection and crossing at that location would result in a safety issue;
6. An ADA compliant curb ramp cannot be designed, and a non-compliant curb ramp approved through an exception would be a safety hazard for users due to excessive slope, cross slope or other existing physical constraints;
7. The crosswalk would not have adequate stopping sight distance based on the design speed, or
8. A physical barrier exists that prevents roadway crossing.
9. In the event that a crosswalk is closed, appropriate signs/barriers should be provided. 
10. A curb ramp should be constructed but signed as "crosswalk closed" if an accessible pedestrian path is not available on the opposite side of the street in the natural path of pedestrian travel but is reasonably expected to be built within five years.

250.3.10 Bulb Outs (Curb Extensions)

Bulb outs are typically used to span parking areas on arterials and collectors to make pedestrians more visible, reduce pedestrian crossing length and should be provided in the following instances:

1. At midblock crossing locations and intersections within the UGB with adjacent established on-street parking along arterial and collector roadways.
2. As required by the Sunnyside Village Community Plan or similar community or design plan area standards in the Comprehensive Plan.
3. At other locations determined by Engineering.

250.3.11 Midblock Crosswalks

1. Marked midblock crosswalks may be considered in the UGB in the following cases and may be provided if warranted per the MUTCD:
2. On arterial or collector roadways with a posted speed of 35 MPH or less where existing intersections, proposed intersections, or existing crossing opportunities are more than 330 feet apart.
3. In locations of existing or anticipated moderate to high pedestrian volumes.
4. Midblock crosswalks should be designed and constructed with the following features:
5. Generally pursuant to the recommendations of Table 9.5 of ITE's Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable Communities:  An ITE Proposed Recommended Practice.
6. With a raised concrete median per Section 250.10 when crossing three or more lanes of traffic.
7. Curb ramps meeting ADA requirements as identified in the ADA Assessment Checklist – Curb Ramps should be provided on both sides of the street per these Standards.

250.3.12 Pedestrian Facility Condition & Repair

1. For pedestrian facilities under the jurisdiction of Clackamas County, comply with the requirements of the County Code Section 7.03 with regard to vertical displacements, cracks and disrepair.
2. Concrete pedestrian facilities may be ground up to ½" in depth from the original pedestrian facility depth.  When more than ½" depth is proposed or required for removal, the full panel of the pedestrian facility shall be replaced.

250.4 Bicycle Improvements

1. Bicycle facilities should be designed and constructed per the Oregon Bicycle and Pedestrian Design Guide, the AASHTO Guide for the Development of Bicycle Facilities and with consideration given to NACTO's Urban Bikeway Design Guide.
2. Separated bicycle facilities shall be provided on all collector and arterial roadways.
3. The location of planned bicycle facilities is established by Comprehensive Plan Map V-7a in the urban area and V-7b in the rural area.
4. The Comprehensive Plan and Active Transportation Plan provide guidance on bicycle facility selection.
5. Bicycle facilities shall be provide travel in both directions along a roadway, where planned.

250.4.1 Shared Use Paths

See Section 250.3.3.

250.4.2 Other Bicycle Facilities

See the Oregon Bicycle and Pedestrian Design Guide, the AASHTO Guide for the Development of Bicycle Facilities, and NACTO Urban Bikeway Design Guide for design guidance.

250.5 Transit Improvements

The applicant shall evaluate existing transit amenities and work with transit providers to determine if transit feature improvements are necessary based upon established transit agency guidelines.  Each project shall provide reasonable accommodations for the incorporation of public transit per transit design guidelines. 

250.6 Horizontal Alignment

250.6.1 Horizontal Curves

1. The horizontal alignment of County, public and private roadways shall conform to the following requirements:
   1. The centerline alignment of roadway improvements shall be common to the centerline of the right-of-way or access easement unless otherwise approved by Engineering.
   2. The centerline of a proposed roadway extension shall be aligned with the existing centerline.

   3. Horizontal curves shall meet the minimum radii requirements shown in Table 2-13.  The minimum horizontal curve radii are determined by the following formula:

      R = V2/(15 (e+f))
      where R = minimum centerline radius (ft)
      V = design speed (MPH)
      e = rate of roadway superelevation (ft/ft)
      f = side friction factor
      Table 2-13

2. Very low volume local roads with ADT less than or equal to 400 may use a centerline radius of 178 ft per AASHTO's Guidelines for Geometric Design of Very Low-Volume Local Roads.  Exceptions for very low-volume local roads can be found in Section 250.6.3.
3. Residential driveways that serve no more than three lots, and are less than 400 feet in length or have topographic constraints may use a 50 foot centerline radius for a 12 foot width or 40 foot centerline radius for a 20 foot width.  Engineering and emergency service provider approval is required.

250.6.2 Design Intent for Horizontal Curves

Minimum radii may be used only as approved by Engineering.  The following excerpts from AASHTO's A Policy on Geometric Design of Highways and Streets and ITE's Urban Street Geometric Design Handbook clarify the use of minimum radii and are adopted by Engineering as general design controls:

Per AASHTO Chapter 3 - Elements of Design, "General Controls for Horizontal Alignment": 

1. "Winding alignment composed of short curves should be avoided because it usually leads to erratic operation."
2. "In an alignment developed for a given design speed, the minimum radius of curvature for that speed should be avoided wherever practical."  
3. "Abrupt reversals in alignment should be avoided.  Such changes in alignment make it difficult for drivers to keep within their own lane." 
4. "The broken-back or flat-back arrangement of curves (with a short tangent between two curves in the same direction) should be avoided… "

Per AASHTO Chapter 3 - Elements of Design, "General Design Controls":

1. "Sharp horizontal curvature should not be introduced at or near the top of a pronounced crest vertical curve.  This condition is undesirable because the driver may not perceive the horizontal change in alignment, especially at night." 
2. "…sharp horizontal curvature should not be introduced near the bottom of a steep grade approaching or near the low point of a pronounced sag vertical curve."  
3. AASHTO Chapter 5 - Local Roads and Streets, "Local Urban Streets", Page 5-12:
4. "[Local urban] street curves should be designed with as large a radius curve as practical, with a minimum radius of 100 feet."

Per ITE, Chapter One 1.6.3:

"Although local streets may be planned, constructed and operated with the primary purpose of providing access to adjacent property, some local streets also may serve a limited amount of through traffic due to street network deficiencies.  In these situations, the designer should utilize geometric design and traffic control features more typical of collector streets to encourage the safe and efficient movement of all street users."

250.6.3 Exceptions for Very Low Volume (≤400 ADT) Local Streets with a Speed of 25 MPH or less

The following are allowed under the listed circumstances on a limited basis:

1. Horizontal curves on local roadways within residential areas may have a minimum centerline radius of one hundred (100) feet as limited in this section.
2. A single 15 MPH maneuver is allowed on a local road on a limited basis when physical constraints or property boundary limitations exist.
3. A 100 foot tangent length shall be provided between low speed maneuvers.  The tangent length provides the driver adequate time to recognize the maneuver and slow down to accomplish the turn.

250.6.4 Roadway and Marking Transitions

Shifts in roadway alignment, widening, or narrowing within motor vehicle travel lanes shall be accomplished through roadway transitions as described below. 

1. Roadway transitions within through lanes or left turn lanes:

   L = S x W (S ≥ 45 MPH)
   L = WS²/60 (S < 45 MPH)

   where L = minimum taper length (ft)
   S = design speed (MPH)
   W = offset (shift) width (ft)

2. Exclusive right turn lanes shall have a minimum 8 (length) to 1 (offset) widening taper for design speeds 35 MPH and below and 15:1 for design speed of 40 and above.
3. On all bike facilities and all paved shoulders, roadway width transitions shall have a minimum 8 (length) to 1 (offset) pavement taper for design speeds 35 MPH and below and 10:1 for design speed of 40 and above.
4. Along local and connector roads within the UGB, roadway width transitions are not required if traffic is not expected to utilize the shifting roadway.

250.6.5 Lane Widths

The Comprehensive Plan and these Standards present a range of lane widths.  Engineering will utilize will consider the following when making decisions about lane widths:

1. Lane widths should be kept as narrow as possible. 
2. Wider lane widths should be considered when the mix of heavy vehicles is greater.
3. When no bicycle facility or shoulder is present, a shy distance from a vertical curb should be considered.
4. If the purpose of the design is a lower speed environment, narrower travel lanes should be selected.
5. The Active Transportation Plan for guidance on the type and width of bicycle facilities.

250.7 Vertical Alignment

The vertical alignment of the County's public and private roadways shall conform to the following requirements:

250.7.1 Minimum Roadway Gradient

1. The minimum tangent roadway gradient shall be 1% along the crown and vertical curb line. 
2. A minimum of 0.5% may be designed with concrete curb and gutter with Engineering approval.
3. Through curb ramps, the minimum gradient shall be designed to 1.0% to 1.5%

250.7.2 Maximum Roadway Gradient

The maximum roadway gradient shall be based on Standard Drawings C110-C140.  Grades in excess of these maximums may be approved by Engineering on a case-by-case basis per Section 170.

250.7.3 Intersection Landing

1. At intersections, a landing shall be provided on the secondary or subordinate approach or on a stop-controlled approach.
2. Landings should be 20 feet in length for private driveways, 50 feet in length for local roadways and one hundred 100 feet in length for all other roadways.
3. Landings should be measured from the edge of pavement of the intersected roadway at full development and shall have an average grade of not greater than 5%.

250.7.4 Vertical Curves

1. Vertical curves shall be used when design grade breaks of more than 1% are necessary.

2. Vertical curves shall conform to the values in Table 2-14 and calculated as below. 

   K = L/A  

   where A = algebraic difference in grades (percent)
   L = length of vertical curve (feet)
   Table 2-14

3. The minimum vertical curve length shall be fifty (50) feet.
4. K-Sag values may be reduced to K-Crest values if adequate street lighting is present along the entire sag vertical curve. 

250.7.5 Roadway Widening

1. Required road widening for land use approvals generally require a half street improvement; however, when one or more of the following apply up to a full street widening may apply:
   1. Setting new curbs;
   2. Centering up road improvements in the right-of-way;
   3. Existing cross slopes are below the minimum or above the maximum standards;
   4. Cross slopes vary from one side to the other; or
   5. Offset crowns exist.
2. Road widening shall not reduce existing road structural sections beyond the minimum standard structural section unless the road structural section is reconstructed to standards.
3. Road widening designs require designed cross sections at 25' on center that illustrate the elevations at:
   1. Centerline of right-of-way,
   2. Crown of road,
   3. Saw cut line, and
   4. Gutter line
      1. Show the existing and new cross slopes between elevation points;
      2. Provide the station for each cross slope;
      3. These cross slopes are usually for plan review to insure that the cross slopes and crown are designed within the acceptable standards and can be provided as a separate exhibit to the plans unless they are also needed to provide information to the contractor.
   5. The maximum grade break between existing and proposed cross slopes shall be 2%.
   6. Cross sections through existing driveways and intersections shall be provided.

250.7.6 Superelevation

1. Design elements for superelevation should be based on AASHTO guidelines.
2. Superelevation is not allowed on roadways with a design speed of 35 MPH or less.
3. The maximum rate of roadway superelevation for urban conditions should be 4% (emax = 0.04).
4. The use of superelevation in the urban area is discouraged and shall be approved by Engineering before used.

250.8 Intersections

250.8.1 Minimum Curb Radii

1. Minimum curb radii at intersections within the UGB are shown in Table 2-15. 
2. Minimum curb radii at intersections outside the UGB are determined by Engineering.
3. The minimum right-of-way radii shall be sufficient to maintain at least the same distance from right-of-way to edge of pavement or curb as the lower classified roadway.
4. Curb radii shall be designed to accommodate the design and control vehicle per Section 250.1.3.
5. Curb radii shall be approved by Engineering based upon an assessment of design and control vehicle considerations as well as pedestrian and design speed considerations.
   Table 2-15

50.8.2 Intersection Angle

The intersection angle at intersecting roadways shall be kept as near to 90 degrees as possible.  Intersection angles from 80 to 85 degrees and 95 to 100 may be considered per Section 170. 

250.8.3 Roadway/Lane Offset

New lanes, roadways or driveways intersecting an existing intersection should not be significantly offset from the existing alignment.  Minor offsets may be approved where low speed maneuvers are predominant or where otherwise acceptably safe operations would occur. 

250.8.4 Tangent Section

In order to improve the safety at intersections, new intersections should conform to the following tangent requirements unless otherwise approved by Engineering.  The following tangent sections should be provided per Table 2-16.

Table 2-16

250.8.5 Residential Intersection Design

Four-legged intersections should be considered for neighborhood traffic circles per Section 265. 

250.8.6 Roundabouts

1. Roundabout intersections shall be designed in accordance with FHWA's Roundabouts:  An Informational Guide.
2. Roundabouts shall be considered per Section 260.1.1 prior to the approval of a traffic signal.
3. Roundabouts with pedestrian facilities shall be designed to comply with ADA requirements as identified in PROWAG Section R306.3.

250.8.7 Intersection Sight Distance

Comply with intersection sight distance requirements of Section 240.

250.8.8 Turn Lane Design

1. The need for left or right turn lanes shall be based upon a traffic study per Section 295.18.1 and/or as dictated by the Comprehensive Plan or CIP.
2. Queue storage estimates shall be based upon a traffic study per Section 295.16.
3. Left turn lanes, when provided, shall have a storage queue of at least 50 feet.
4. Design of left or right turn lanes should be based upon ODOT's Highway Design Manual. 

250.9 Roadway Grading

1. Roadway grading should conform to clear zone requirements of Section 245 and cross section requirements of Standard Drawings C110 to C140.
2. Slopes along and adjacent to the roadway should be as specified in Standard Drawings C110 to C140.  The maximum slopes outside the clear zone as detailed in Section 245 are as follows:
3. Cut Slope - 2 to 1
4. Fill Slope - 2 to 1
5. Roadway embankment should be constructed with crushed aggregate no larger than 6"-0 and no larger than 1½"-0 to 3"-0 can be used within one-foot of the structural section of the roadway.
6. Flatter slopes are preferred and may be required by the County if soils are unstable as determined by a geotechnical analysis.
7. Side slopes exceeding four feet in height shall be constructed in conformance with design and specifications prepared by an Engineering Geologist or Geotechnical Engineer.  All side slopes shall be stabilized by grass sod, seeding, riprap, or other acceptable ground stabilizing materials as recommended by a geotechnical engineer.
8. Side slopes necessary for roadway stability extending outside the public right-of-way will require slope easements.

250.10 Non-traversable Medians and Accessible Route Islands

1. Non-traversable medians should be required in the following cases:
2. On arterial roadways within the UGB with five or more travel lanes.
3. When described as an element of a project listed an adopted plan.
4. On roadways where right-in/right-out driveway access maneuvers are required.
5. Non-traversable medians should be considered in the following cases:
6. On arterial or collector roadways within the UGB with three or more travel lanes.
7. On roadways where improved access management is desirable.
8. Medians should be designed and constructed with the following features:
9. Landscaping per Section 255.
10. Landscaping with a mature height of 2.5 feet should not be planted within 50 feet of an intersection.
11. With a minimum width of eight feet when designed to serve as a pedestrian refuge. 
12. With a minimum width of one foot when not designed to serve as a pedestrian refuge.
13. To contain a "shy" distance from adjacent traffic of varying width depending upon the design speed of the roadway.
14. Medians that are crossed by a pedestrian access route and accessible route islands shall comply with ADA requirements as identified in ADA Design Review Checklist – Medians/Traffic Islands and depicted in Oregon Standard Drawing RD710. 

240.1 General

Sight distance shall be determined and approved in accordance with the procedures as stated in the current AASHTO "A Policy on Geometric Design of Highways and Streets" or AASHTO's "Guidelines for Geometric Design of Very Low-Volume Local Roads (ADT ≤ 400)". 

240.2 Sight Distance – Standard

1. Comply with the requirements of County Code Section 7.03 which requires that no person shall place objects in the right-of-way or private property in such a way that they limit ISD or SSD per Table 2-6 to 2-10.
2. Adequate intersection sight distance ("ISD") and adequate stopping sight distance ("SSD"), per Tables 2-6, 2-7, and 2-8, should be provided at all existing intersections and shall be provided at all new intersections.
3. Adequate intersection sight distance ("ISD") and adequate stopping sight distance ("SSD"), per Tables 2-6, 2-7, and 2-8, should be provided at all proposed accesses and existing accesses that are subject to land use approval that increase in ADT by 21 or more.
4. Sight distance at intersections and accesses to very low volume local, connector and collector roadways with a 20 year entering volume of less than or equal to 400 ADT and meeting the eligibility requirements of Table 2-9 may be based upon Table 2-9.
5. Existing access subject to land use approval where ADT is increased by 20 or fewer trips shall provide adequate SSD per Table 2-10.
6. Existing access not subject to land use approval but subject to a permit shall maximize ISD and SSD by removing visual obstructions located on the applicant's property or located in the road right-of-way.
7. Proposed access to parcels or contiguous parcels with no other access and not subject to land use approval but subject to a permit shall maximize ISD and SSD by removing visual obstructions located on the applicant's property or located in the road right-of-way.
8. Adequate SSD should be provided along all roadways per Table 2-10 except very low volume local roads, which may be based upon Table 2-9.
9. Adjustments to the sight distance tables of these Standards for street grade, design vehicle, or other factors, with regard to ISD and SSD requirements, shall be made per AASHTO guidelines.
10. If required ISD or SSD cannot feasibly be achieved, lesser sight distance may be acceptable per Section 170.

 An applicant may be required to provide evidence that proposed improvements will not create situations where sight distance is made inadequate for other driveways, intersections, or other sections of roadway.  If sight distance for existing driveways, intersections or sections of roadway is already inadequate, the applicant shall provide evidence that sight distance is not worsened by the applicant's improvements.

Access that doesn't comply with the above criteria are subject to denial, removal or modification.

40.3 Existing Offsite Public Roadway Intersections

Proposed developments subject to adequate safety requirements of the ZDO that impact off-site public roadway intersections (public road intersecting another public road) may be subject to ISD and SSD adequacy requirements at those off-site intersections if safety issues may result from the proposed development in the judgment of the Road Official.  A development may be found to impact off-site intersection(s) if the development's only access or all directions of access to the nearest collector or arterial road is/are via intersection(s) turning movement(s) with inadequate ISD or SSD per Section 240.2.  The applicant may be responsible for submitting data that substantiates trip movements.  The following criteria apply:

1. Developments that add a minimum of 15 daily trips to the inadequate movement(s) at the off-site intersection(s) may be required to mitigate that/those intersection(s) along at least one route from the site access to the nearest collector or arterial roadway per the standards of Section 240.2 or be denied access; or
2. Developments that add between five and 14 daily trips to the inadequate movement(s) at the off-site intersection(s) may be required to mitigate that/those intersection(s) along at least one route from the site access to the nearest collector or arterial roadway per the standards of Table 2-10 and measured per Section 240.4 or be denied access; or
3. Developments that add less than five daily trips to the inadequate movement(s) at the off-site intersection(s) will only be required to mitigate that/those intersection(s) along at least one route from the site access to the nearest collector or arterial roadway per the standards of Table 2-10 and measured per Section 240.4 if any of the off-site intersections are experiencing a crash history related to the inadequate ISD, inadequate SSD or if the development is anticipated to create a significant safety issue.

240.4 Intersection Sight Distance Measurement

ISD shall be measured from a driver's eye height of 3.5 feet and 14.5 feet from the edge of the nearest travel lane (edge line, bike lane line or if neither exits, edge of pavement) to an object height of 3.5 feet above the roadway surface and measured along the center of a travel lane.  Sight distance measurements shall be modified under the following conditions:

1. Where a significant percentage of trucks will intersect a roadway, sight distance measurements may also dictate compliance with the truck sight distance measurements of AASHTO.
2. At the intersection of a local roadway and a private driveway serving up to two single family residential homes, sight distance may be measured 10 feet from the edge of the nearest travel lane except where backing maneuvers are likely to occur.

240.5 Stopping Sight Distance Measurement

SSD shall be measured from a driver's eye height of 3.5 feet to an object height of 2.0 feet above the roadway surface and measured along the center of a travel lane.

240.6 Sight Distance Design Speed

Design speed, for the purpose of determining sight distance, shall be based upon the guidance of Section 250.1.2.  If desired or required, a speed study shall be completed by the applicant in conjunction with County staff direction.   

Table 2-6
Table 2-7
Table 2-8
Table 2-9
Table 2-10

230.1 General

The following standards shall apply to the design of residential, agricultural and logging driveways approaching public or private roadways.  County Code Section 7.030.240 provides some exceptions to the requirements below.  The Entrance Permit Matrix provides additional requirements. 

230.2 Standard Drawings

Driveways that intersect with a proposed or existing sidewalk or other pedestrian facility shall meet ADA accessibility requirements and should be constructed in conformance with the applicable standards depicted in the most recent versions of Oregon Standard Drawings RD725, RD730, RD735, RD740, RD745, or RD750.  Residential, agricultural and logging driveways shall be constructed in conformance with the applicable standards depicted in Standard Drawings D250 through D700. The County shall determine the specific driveway detail, based upon the existing and planned improvements.

230.3 Provisions for ADA Accessibility of Driveways

1. All new or altered driveways required to meet ADA accessibility standards shall meet the PROWAG standards for a Pedestrian Access Route whether or not the driveway is connected to sidewalk or path.
2. The driveway shall provide a connection on both sides to existing or planned sidewalk or path, at a location identified by DTD.
3. The pedestrian access route across the driveway shall be at least 5 feet wide perpendicular to the direction of pedestrian travel with a cross slope of no more than 2% and a grade in the direction of pedestrian travel that does not exceed the grade of the adjacent street.
4. The edge of the pedestrian access route on the driveway shall be flush with the adjacent sidewalk or path with a vertical surface discontinuity of no more than ¼ inch.
5. If it is necessary to provide ramp(s) connecting the driveway pedestrian access route to the adjacent sidewalk or path, the ramp shall have a running slope in the direction of pedestrian travel no more than 8.33%, ramp length not to exceed 15 feet, and cross slope no more than 2%.
6. If the driveway serves commercial uses and is 50 feet or more wide, or stop controlled, or both, truncated dome texture contrast shall be provided perpendicular to the direction of pedestrian travel on the sidewalk on the transition from the adjacent sidewalk or path to the driveway on both sides. The truncated dome texture contrast shall extend 2 feet in the direction of pedestrian travel and completely across the sidewalk.

230.4 Driveway Vertical Geometry

1. For residential driveways, the average driveway grade shall not exceed 12%, and no grade shall exceed 15% for gravel driveways or 20% for paved driveways. 
2. All grades in excess of 12% shall be approved by the fire district. 
3. The grade break for all driveways shall be a maximum of 9%.  Grade breaks in excess of 9% shall require vertical curves with a minimum K value of one (1). 
4. Vertical transitions shall be designed for the design vehicle to not "bottom out" at minimum.  The functionality of the intersecting roadways shall be considered to ensure that vehicles on major roadways are not excessively slowed or endangered by driveway operations. 
5. For residential driveways, vertical clearance shall not be less than 13.5 feet.
6. Steep, uphill driveways having greater than a ten percent grade shall be constructed with diagonal water bars (berms) to assure that water from uphill properties is directed into the ditch line.  In drainage situations which will not be remedied by valley gutters or water bars, it is the responsibility of the owner to construct ditches, etc., to prevent damage to the roadway or danger to the traveling public. 

230.5 Driveway Horizontal Geometry

1. Standard driveway throat widths for agricultural and logging driveways and residential driveways vary from a minimum of 12 feet to a maximum of 35 feet at their intersections with public roadways.  Driveway widths should be minimized.  A truck turning analysis should accompany any design modification requests.
2. Horizontal clearance shall not be less than 20 feet for driveways subject to fire access requirements.
3. Minimum centerline curve radius shall be 50 feet for driveways subject to fire access requirements.
4. Turnaround geometrics shall conform to Standard Drawing C350 or C300, as applicable. 

230.6 Driveway Structural Capacity

For driveways subject to fire access requirements, roadway base, bridges, and culverts shall be capable of supporting a 75,000 pound fire truck.  See Chapter 5 regarding requirements associated with structures such as walls, bridges and other structures.

230.7 Emergency Services

1. All residential and agricultural driveways longer than 150 feet in length shall be designed to provide for fire access and shall be provided with an emergency vehicle turnaround area at or near the driveway termination. 
2. Residential and agricultural driveways with a travel surface less than 20 feet wide and in excess of 400 feet in length shall have a turnout every 400 feet per Standard Drawing C350 at locations approved by the fire district.
3. Gates shall be placed a minimum of 30 feet from back of sidewalk or edge of pavement.  If queues are likely to extend into the travel lane of the nearest roadway, then a queuing analysis shall be provided per Section 295.  Gates may require the approval of the fire district. 
4. Exceptions to these standards are illustrated in the Entrance Permit Matrix.

230.8 Driveway Surface Water

1. Surface water runoff shall not be allowed to flow along or across an access or entrance from private property onto the travel surface of the roadway.
2. Driveways and buildings that increase impervious surface by the thresholds described in Chapter 4 are subject to stormwater management requirements.
3. Requirements for erosion control shall be addressed per Chapter 4.

230.9 Driveway Culverts

1. All driveways on non-curbed roadways shall have culverts for proper road drainage unless Engineering determines that they are not required. 
2. Culvert installations are typically not required on paved and curbed roads.  The installation of driveway culverts to control surface runoff shall be required as deemed necessary by Engineering.
3. Driveway culverts shall provide a minimum 12 inch inside diameter.  Larger culverts are required based upon the design calculations and under the following conditions:
4. Culverts shall be designed to convey storm water from the contributing basin for the 25 year storm at full build-out of the basin.
5. When the existing storm sewer culverts above and below the proposed driveway entry are a larger diameter than l2-inches;
6. When there is evidence that erosion has occurred in the roadside ditch;
7. When there is other evidence to show that a larger diameter would be appropriate.
8. Bedding requirements for concrete and metal culvert pipe shall never be below the Class C bedding specification contained in the Oregon Standard Specifications for Construction.
9. Storm sewer culvert shall have enough aggregate and/or pavement cover to support HS-20 loading per Standard Drawing D250.
10. Notwithstanding the requirements of this subsection, ORS 368.251 to 368.281 shall govern storm sewer culverts and the accompanying entry structure.
11. Culverts shall be maintained in good condition so the flow of storm water is not impeded.

230.10 Intersection Angle

Comply with requirements of Section 250.8.2.

230.11 Permit Requirements

An Entrance Permit or Development Permit, whichever is applicable, shall be obtained from Engineering.

230.12 Inspection Requirements

Comply with requirements of Section 180.

230.13 Intersection Sight Distance Requirements

Comply with requirements of Section 240.

230.14 Maintenance Requirements

The maintenance of existing driveway entries within the right-of-way, including culverts, aggregate, and driving surface, shall be the responsibility of the owner of the property being served by the driveway.  Maintenance must be performed so that the entry does not become a hazard including the responsibility of ongoing management of private property and the right-of-way to maintain sight distance per Section 240.  Additional requirements are provided in County Code Section 7.03.

225.1 Future Extension of Roadways Related to Development

1. When required by land use approval, a proposed development shall construct a public roadway, or private roadway acceptable to the County, to the boundaries of the development to permit future development or division of adjoining land, in order to promote connectivity.
2. A roadway master plan may be required prior to approval of the location of a roadway stubbed to the current development boundary to ensure connectivity of the future roadway system and to retain the development potential of adjacent land.  This master plan shall consider topographical and geographical information and assume maximum development consistent with existing zoned densities.
3. New public roadways that are stubbed to adjacent property with future potential extension may require the construction of a temporary turnaround, depending on the length of the dead end street and/or the dedication of right-of-way for the temporary turnaround or future turnaround.
4. Public streets that cannot be extended shall end in a County approved cul-de-sac or turnaround. 

225.2 Termination of Roadways/Dead End Streets (Cul-De-Sacs, Turnarounds & Hammerheads)

Dead end streets may be allowed when deemed appropriate by Engineering and shall meet the following minimum criteria:

1. Dead end roads are allowed on local and private roads only. 
2. Dead end public roads should terminate in a cul-de-sac.  Alternate designs may be considered on a case by case basis depending on topography, length, ADT, or other design constraints. 
3. Dead end streets are allowed only where topography or pre-existing development precludes roadway connections.
4. A roadway ending in a dead end shall be as short as possible, having a maximum length of 400 feet, serving not more than 18 dwelling units.
5. The length of the roadway ending in dead end shall be measured along the centerline of the roadway from the near side right-of-way of the nearest cross street to the farthest point of the dead end right-of-way. 
6. Dead end streets longer than 400 feet may be approved if no other means are available for development of the property and special provisions are made for: public facilities, pedestrian and bicycle circulation and emergency service access and vehicle turnaround.
7. For dead end streets less than one hundred fifty (150) feet in length, sidewalk is required on one side only, but shall include the entire turnaround area.
8. Cul-de-sac bulbs and other approved turnarounds shall have a maximum grade of 5%
9. Cul-de-sacs shall conform to Standard Drawing C300.
10. For alternate termination designs see Standard Drawing C350.

225.3 Opening or Upgrade of Unimproved or Substandard Public Right-Of-Way to Benefit Private Access

An existing unimproved or substandard public right-of-way may be opened, upgraded, or improved for vehicular access subject to a permit.  Requirements include:

1. Applicants for the improvement shall bear all costs inclusive of survey, engineering, construction and maintenance. 
2. Subsequent to this investment, no proprietary rights or exclusive use to the funded improvement will or could be granted within the public right-of-way. 
3. Case-by-case interpretation of construction standards based on the proposed use is necessary to define the extent of construction, location and width of available existing right-of-way consistent with the proposed use or impact.
4. The applicant may be required to dedicate additional right-of-way or easements along the property frontage and at the terminus as deemed necessary by engineering to comply with County standards.
5. If satisfactory access cannot be constructed within the available public right-of-way, the applicant has the option of acquiring additional right-of-way as required or may seek an alternative private access.

225.4 Off-Site Access Standards

On a case by case basis, the County may require construction of improvements within existing off-site (beyond a development site's frontage) public rights-of-way in order to provide adequate safe access to newly created lots or parcels or for other development.  If Engineering determines that off-site roadway improvements are necessary to achieve minimally adequate and safe traffic flow, such improvements may be required before Engineering can recommend approval of a proposed development.

225.5 Structural and Surface Road Improvements Related to Development

1. The County cross section standards of Standard Drawings C110 to C140, community plans in the Comprehensive Plan or design equivalents, shall be applied to the roadway design and constructed in the course of the development or redevelopment along the site frontage and extended to an off-site roadway as established in site specific land use requirements.
2. Road right-of-way or easement width dedications for roadway or public utility purposes along the site frontage (see Section 160.5) is required to meet the adopted cross section width and any additional width identified in a traffic impact analysis.  
3. Frontage improvements shall typically be designed and constructed to the standard cross section. 
4. Staff may rely upon Table 2-3 as a guideline or other alternatives when the full standards cannot be required. 
5. The extent of frontage improvements typically are based on providing a half street improvement.  Occasionally, a situation may call for more than a half street improvement and will be determined based on:
   1. Location of the existing pavement in relation to the right-of-way;
   2. Pavement width;
   3. Pavement condition;
   4. Centered crown, offset crown, shed or other;
   5. Cross slope;
   6. Road grade;
   7. Elevation of existing curbs within 300' of the property lines, including opposite the development.
6. The extent of offsite tapers will be determined per Section 250.6.4 and by the need to:
   1. Match an offset crown;
   2. Match to existing grades and cross slopes
7. When a fee in lieu of improvements ("FILO") is paid, a development's site frontage should meet minimum widths listed in Table 2-3.  When FILO is paid and the minimum frontage improvements are existing, the applicant shall still provide roadway improvements compliant with utility restoration standards of Chapter 7 and Standard Drawings U275 to U290.
    

Table 2-3.  Frontage Improvement Guidelines

Required Frontage Improvements

Std = Dedicate half street right-of-way and construct standard half street cross sections per Section 225.5.a and 225.5.b
Std R/W = Dedicate half street right-of-way per Section 225.5.a and 225.5.b

1. The applicant may be required to provide an analysis of the pavement and base structural sections to determine the structural section and the current condition of the road.  When required, the analysis shall include:
2. Surface Defects
   1. Raveling & Loss of Surface Aggregate
   2. Flushing
3. Surface Deformations (due to a weak sub-base or instability in the pavement)
   1. Rippling and Shoving
   2. Wheel Track Rutting
   3. Distortion
4. Cracking (caused by either thermal stresses or weak base)
   1. Longitudinal Wheel Track Single and Multiple, Alligator
   2. Centerline Single and Multiple, Alligator
   3. Pavement Edge Single and Multiple, Alligator
   4. Transverse Single and Multiple, Alligator
   5. Longitudinal - Meander or Mid-lane
5. The County will review the analysis to determine if an overlay, grind and inlay or full depth reconstruction is warranted based on the existing conditions of the road, the proposed construction impacts and the ADT with the added development.  Different causes of the pavement condition will warrant different remedies.
6. If an existing County or public road terminates along a development's frontage without the benefit of a cul-de-sac or turnaround and the roadway cannot be extended, the development shall construct a full County cul-de-sac per Standard Drawing C300 or approved turnaround per Standard Drawing C350.

225.6 Construction Haul Routes

Construction activities for some developments should not deteriorate roadways classified as local roads, which are more susceptible to damage due to reduced maintenance and/or structural section.  Clackamas County Transportation Maintenance performs annual pavement condition reviews on county maintained roads and may be able to provide a Pavement Condition Index (PCI) rating for the road but not necessarily at the project site frontage.  Temporary construction access via an Entrance Permit may be granted to avoid impacts to local roads. 

Residential subdivisions, commercial, industrial and multifamily developments that utilize a local road as a haul route for construction or will otherwise impact a local road may be required to improve those roads.  If during the work or at the conclusion of work, there is any visible deterioration or drop in PCI of 8 or more the applicant may be required to provide an overlay, grind and inlay or other sufficient improvement to restore the roadway to as good as or better than before the work was initiated.

Should this be required, the applicant shall provide the following:

1. An exhibit depicting haul routes and the location of the construction entrance(s) for all construction equipment and materials if an existing local road will be utilized prior to intersection with a collector or arterial;
2. Such routes may be subject to possible restrictions or conditions to protect existing infrastructure and address traffic impacts;
3. An existing conditions PCI from County Transportation Maintenance, if available;
4. Photographic/video evidence of the conditions before and after construction;
5. Core samples, as requested, of the pavement and base section, before and after construction;
6. A financial surety of not less than $10,000 or 125% of the cost estimate for addressing anticipated infrastructure improvements along the haul route, whichever is greater, prior to Development Permit issuance;
7. Temporary measures to limit further deterioration of the roadways that are currently in poor or very poor condition prior to Development Permit issuance; and/or
8. The applicant shall maintain affected roads at an acceptable and safe level throughout the work.

225.7 Creation of a Private Roadway

In certain circumstances, creation of a private roadway may be the only reasonable method and alternative to provide access to the proposed lots or parcels.  If connectivity and access to adjacent properties is not an issue, private roadways, as addressed in the ZDO, may be permitted.  The following shall apply:

1. Design and construction of a private roadway shall be consistent with the design standards for public roads, except as noted in these Standards regarding widths, cross section and design speed, and in no case shall improvements be less than minimums set out in Standard Drawing R100. 
2. Provisions should be made through a formal maintenance agreement or equivalent to ensure private responsibility for future maintenance.
3. Private roadways and their respective easements shall be distinguished from public roadways and any reservations, restrictions, and maintenance agreements related to the created private roadways shall be described in the land division plat or deed records.
4. The need for utilities and roadway drainage shall be considered. 

220.1 General

1. Access management for private accesses or public intersections is required to improve safety and efficiency of traffic flow for users of the transportation network and to balance those needs with livability, economy and community values.
2. The location and number of roadway intersections and other access points shall be planned, coordinated and controlled by Engineering.
3. By the nature of the roadway functional classification system, higher speed arterial streets require the highest level of access management restriction tending toward less access.  Lower speed collector streets and connector streets require less restrictive access management.  Local streets require very few access management restrictions and tend towards more frequent access.
4. Chapter 10 of the Comprehensive Plan provides various standards for access within certain Community Planning Areas.  Within those plan areas, access shall be determined according to the Comprehensive Plan.

220.2 General Requirements

Accesses are subject to the sight distance standards of Section 240, the design requirements of Sections 230 and 330, and this section.  Accesses that are not compliant with these requirements may not be approved.  Existing accesses may be required to be removed or modified in order to comply with these requirements.

220.3 Access Spacing Standards

Accesses subject to a land use approval and those subject to spacing standards per the Entrance Permit Matrix shall adhere to the minimum spacing requirements of Tables 2-1 or Table 2-2 and requirements of Section 220.4.  Considering access along both sides of the roadway (i.e. spacing from existing accesses on the south side of a road when an access on the north side of a road is proposed), access spacing shall be measured from the proposed centerline to the centerline of an existing access or roadway or planned roadway.  Planned roadways are those illustrated in the Comprehensive Plan, other local transportation system plans, or those approved as part of an approved development not yet constructed. 

Table 2-1 Minimum Access Spacing Inside the UGB

Table 2.2. Minimum Access Spacing Outside the UGB

*If approved, restricted access spacing implemented typically by raised median only
N/A = Restriced access not consideredd on these roadways.
** Access shall be placed a minimum of 100 feet from any intersection with an arterial roadway. If less than 100 feet of frontage, spacing from the intersection shall be maximized.

Access modifications may be approved per Section 220.6 and Section 170.

220.4 Additional Access Requirements

The following conditions apply in addition to the requirements of Tables 2-1 and 2-2:

1. Existing or proposed accesses subject to land use approval shall first take access to the lower functional classified roadway unless evidence or an engineering study establishes that access(es) to the higher functional classified roadway are needed for safety, circulation, to address topography or environmental constraints, or are otherwise a benefit to the public.  Existing accesses where ADT is increased by ten or fewer trips are not subject to this standard if the sight distance standards of Section 240 are met.   
2. Parcels or contiguous parcels under the same ownership shall be limited to one access except on local or connector roads where the number of accesses is not limited if sight distance and access spacing standards are met. 
3. Accesses subject to the Entrance Permit Matrix that provide the only access to a parcel or contiguous parcels under the same ownership shall comply requirements of Table 2-1 or 2-2 to the extent feasible.  First priority will be given to achieving adequate sight distance per Section 240, second to access by functional classification per 220.4(a) and (b) and third to access spacing requirements.  Based on the judgment of the Road Official, the access will be placed in the safest location. 
4. Commercial, multifamily and industrial developments that can comply with spacing standards to collectors and arterials may request additional access but shall establish that the proposed access is/are needed for safety, circulation, to address topography or environmental constraints, or are otherwise a benefit to the public. 
5. Reciprocal access easements may be required even if these standards are met in order to promote connectivity and to reduce conflicts on the public street system.
6. On roadways with an ADT greater than 1000 and outside the UGB, additional access(es) may be permitted on collectors, minor arterials and major arterials for logging, agricultural, and accessory structure use when sight distance, functional classification, and spacing standards are met, and for all uses when needed to address safety, circulation, to address topography or environmental constraints, or are otherwise a benefit to the public.
7. On roadways with an ADT less than or equal to 1000 and outside the UGB, additional access(es) may be permitted on collectors, minor arterials and major arterials for all land uses when sight distance, functional classification and spacing standards are met.
8. Conflicting access movements within the 95th percentile queue of any traffic movement of an intersection may be reason to deny, relocate or restrict access.  A traffic study complying with Section 295 will be required if this is a likely issue. 
9. Accesses that serve only emergency vehicles are exempt from these requirements.  However, these accesses shall be gated.
10. Accesses, other than those to a local or connector roadway, that require any vehicle to back onto a public roadway are prohibited.

220.5 Roadway Intersection Management

New developments that will require construction of new streets shall provide full street connections at intervals of no more than 530 feet, where feasible. If full street connections are not feasible at such intervals, accessways for pedestrians, bicyclists or emergency vehicles at intervals of no more than 330 feet shall be provided. Exceptions may be made where there are barriers, including topography, railroads, freeways, pre-existing development, existing easements, or environmental constraints such as streams and wetlands."

No public roadway/public roadway intersection may be offset by less than 100 feet unless approved per Section 250.8.3.

Comply with requirements of Section 225.1.

220.6 Modification Considerations

1. All access requests not meeting these standards for access shall include a scaled site plan and a traffic report if required by Engineering.  The scope of the development will determine the information required and shall comply with Sections 170 and 295.  The evaluation of the access request will consider the impacts that traffic generated by the proposed development will have on through traffic, traffic patterns, traffic queuing, and safety.
2. If approved, access may be restricted to right-in/right-out movements or other movement restrictions.

1. The functional classification of existing and planned roadways has been established by the Comprehensive Plan, Chapter 5 - Transportation.  Design standards for new roadway construction and existing roadway improvements are based on these functional classifications.  The functional classification of a roadway determines how the roadway will be designed.
2. Functional classifications of individual roadways can be found on Maps 5-4a and 5-4b of the Comprehensive Plan.  Descriptions of each functional classification can be found Chapter 5of the Comprehensive Plan. 
3. Roadway design shall consider the Regional Street Design Type Guidelines as described per Comprehensive Plan policy 5.O.5 as illustrated in Map 5-5. 
4. Community Planning Areas, as referenced in the Comprehensive Plan, have exceptions to these Standards.  Otherwise, Standard Drawings C110 through C140 shall be used for design of roads under the jurisdiction of Clackamas County.
5. Use of Urban Alternate 1 and 2 sections per Standard Drawing C110 may be considered on very low volume roads or roads that cannot be extended, and where the alternate street section would better accommodate:
   1. Sustainable surface water management solutions such as low infiltration planters and basins, swales, ponds, rain gardens, trees, and minimal disruption to natural drainage systems;
   2. Preservation of existing significant trees and native vegetation;
   3. Preservation of natural terrain and other natural landscape features; and
   4. Existing development.
6. All other roadway design shall comply with these Standards.

Chapter 2 establishes the technical requirements associated with roadway design and construction.  

Roadways in Clackamas County should be designed as follows:

1. For the safe and efficient travel of all users of the transportation system. 
2. To meet or exceed the minimum design guidelines referenced herein.  Considerations will be made to best accommodate interrelationships of existing and proposed roadways, topographic conditions and the land use to be served by the roadway.
3. To flexibly consider roadway context with regard to the mix of users, adjacent land use, type of traffic, traffic volume, and speed of traffic to be carried.

To comply with the cross section elements illustrated in the ZDO, Comprehensive Plan and the CIP.

190.1 General

To ensure the acceptable completion of permitted private or public improvements, a Performance Surety and/or Warranty Surety may be required and integrated into Engineering related permits.

1. A Performance Surety shall be required prior to:
   1. Issuance of a Utility Permit for mainline utilities or other utility work that significantly impacts the existing roadway except when performed by a "public utility company or municipal authority" per County Code 7.03.130.E. Per County Code, if an existing roadway is left in disrepair and is a hazard to the traveling public, the County may repair the road and call the surety to cover the cost of repairing the road. If the Performance Surety is redeemed to repair a road during the course of a project, an additional surety may be required by the County to complete the project;
   2. Issuance of a Development Permit impacting an existing roadway under the jurisdiction of the County. If at any time, an existing roadway is left in disrepair and is a hazard to the traveling public, the County reserves the right to repair the road or call the surety to cover the cost of repairing the road. If the Performance Surety is redeemed to repair a road during the course of a project, an additional surety may be required by the County to complete the project;
   3. Issuance of a Certificate of Occupancy when all improvements required by the Development Permit and the land use requirements are not completed and accepted; or
   4. Recordation of a plat when all improvements required by the Development Permit and the land use conditions are not completed and/or accepted.
   5. A Performance Surety may be required prior to issuance of a Right of Way Permit for events that have a strong potential of damage occurring to the right-of-way.
2. Substantial Completion of residential partitions and subdivisions shall be achieved prior to acceptance of any surety for guarantee of work to record a plat.  Requests for acceptances of a surety for guarantee of work without achieving Substantial Completion will be evaluated by Engineering using the criteria in Section 190.2 if minimum fire, life and safety issues are met.
3. A Warranty Surety shall be required for improvements located in the right-of-way under County jurisdiction after the acceptance of improvements.

Typically, Performance Surety or Warranty Surety will not be required for Entrance Permits or Right-of-Way Permits, but may be required by the Road Official.

190.2 Substantial Completion for Development Permits

Substantial completion is achieved when:

1. All required right-of-way dedications and easements have been accepted or are shown on the final plat.
2. The sanitary sewer mainline and service laterals under subject roadways are constructed and accepted.
3. The roadway drainage system is constructed and accepted, including LIDA when required.
4. The water main line and service laterals are constructed and accepted and water is available for fire suppression.
5. Conduits for franchise utilities within the roadway are installed and accepted.
6. The pavement wear course is installed.  If pavement is not required, the full gravel structural section has been placed and properly compacted.
7. Shared private roadways and emergency access turnouts and turnarounds are constructed.
8. All other land use or Development Permit conditions required to be met prior to plat or occupancy approval are completed.
9. The EOR shall complete a Certificate of Compliance and Completion.

190.3 Performance Surety

Acceptable Performance Sureties include a Performance Bond, a Security Agreement (commitment of funds), or a Cash Acknowledgement.

1. Performance Bonds shall be provided only through State regulated surety companies
2. A Security Agreement, or commitment of savings or loan proceeds, shall be through State regulated financial institutions. 
3. A Cash Acknowledgment is a cash surety held directly by the County.
4. A Development Agreement shall accompany all types of sureties and be recorded.

190.3.1 Forms

All sureties and Development Agreements shall be submitted on forms provided by the County and are subject to review and approval by County Counsel.

190.3.2 Timeframe/h3>

Sureties shall be in effect at the time of plat approval or issuance of a Certificate of Occupancy and until County acceptance of the improvements resulting in release of the surety. 

190.3.3 Amount

1. The financial amount established for the Performance Surety shall be equal to 125% of the estimated value of the improvement. 
2. An Engineer's estimate is required and shall be approved by Engineering.  A contractor's bid or estimate is not acceptable.  The surety shall cover the County's cost for completing the work with public contracting procedures and include project management and inspection services.
3. The minimum amount for Performance Sureties shall be $10,000.  The minimum amount for all other sureties including the Cash Acknowledgment shall be $2,500.
4. Engineering will not approve more than one surety reduction throughout the life of the project, not including the reduction of Performance Surety to the Warranty Surety.

190.4 Maintenance and Warranty Period for Development Permits

1. Typically, the Warranty Period will begin when all improvements, with the exception of street trees, are accepted by the County.  If there are remaining improvements to be constructed, the Warranty Surety will also include a Performance Surety.  All outstanding performance items shall be guaranteed at 125%. This combined surety may require the minimum warranty period to be extended to two years from the date all performance improvements have been completed.
2. The applicant shall provide a Warranty Surety as part of a Development Permit for work located in a public right-of-way under County jurisdiction.  The Warranty Surety/maintenance requirements shall be held for a minimum of two years.
3. The required Warranty Surety shall be valued at 25% of the Engineer's estimate and approved by Engineering.
4. The County may require an extension of the Warranty Surety/maintenance period for more than the minimum required if the required improvements show signs of failure during a final inspection and work is completed to correct these deficiencies.
5. The Warranty Surety does not expire and may only be released after a final inspection has been completed and the minimum warranty period has elapsed. At the time of final warranty inspection, any items not completed or maintained to County standards will be included in a punch list provided to the applicant and/or guarantor. These items shall be addressed prior to the release of the Warranty Surety.

190.5 Maintenance and Warranty Period for Utility Permits

1. Utilities installed as part of Utility Permits do not have a Warranty Period.
2. When related to a Development Permit, the Warranty Surety/maintenance requirements for utility work will follow those listed under 190.4 for work located in a public right-of-way under the jurisdiction of the County.

190.6 Acceptance of Work

Prior to County acceptance of the improvements and release of the Performance Surety and/or Warranty Surety/maintenance period, the following shall occur:

1. The applicant shall repair any damage caused by the construction of the work to any public roads, private roads and/or property that is not part of the project as well as any identified haul routes per Section 225.6.
2. The applicant shall perform a thorough cleaning of the roadway surface and storm drain system.
3. If a private PI is required, the PI shall conduct an inspection of the improvements.
4. If the private PI indicates that the work is complete, the EOR shall complete a Certificate of Compliance and Completion.
5. The County shall conduct an inspection of the improvements.
6. The County shall make a determination of completion in conformance with the permit. 
7. Any deficiencies resulting in non-acceptance of the work permitted in the Development Permit shall be identified in writing on a punch list and presented to the applicant with a date named for correction and completion. 
8. Upon correction of the noted deficiencies and the determination that all work is in conformance with the requirements, repeat steps a) through f).
9. When the improvements are found complete and the work is accepted, the Performance Surety will be released and the Warranty Period will begin.
10. Once the Warranty Period has passed, and there are no defects in workmanship found by County inspection, the Warranty Surety will be released.

190.7 Acceptance of Roads

When the permit requirements are met and the Warranty Period is over and all sureties have been released, the County will then accept the road right-of-way as dictated by the road's classification. 

190.8 Nonperformance of Permit

Failure to complete the project prior to expiration of the Development Permit and Utility Permit shall be construed as nonperformance and may be considered a violation of the permit.  The surety may be demanded in order to bring the project to completion.  If compliance is not achieved, the permit is subject to code enforcement.  Development Agreements should not be extended unless there is adequate surety to guarantee the improvements through the extended period.

180.1 General

The applicant shall provide the County with access and be furnished with every reasonable facility for inspection of the work, is in accordance with the requirements and intent of the plans, specifications, permit conditions and land use requirements (collectively known as "the permit").

180.2 County Inspector Authority and Duties

A County inspector will be assigned to each project to inspect materials and work performed.  Such inspection may extend to any or all parts of the work and to the preparation and/or manufacture of the materials to be used.

The County inspector is not authorized to:

1. Revise, alter, or relax requirements of the permit.
2. Direct how the work is to be performed.

The County inspector has the authority to:

1. Inspect work performed and materials furnished, including without limitation, the preparation, fabrication, or manufacture of materials to be used.
2. Reject deficient materials or work.  The inspector may advise the applicant or contractor of any faulty work or materials; however, failure of the inspector to advise the applicant or contractor does not constitute acceptance or approval. 
3. Temporarily suspend the work for safety deficiencies for safety issues, lack of compliance with the permit, or if the requirements of a private primary inspector are not being fulfilled per Section 180.3.
4. Recommend revisions or revocation of the permit per Section 130.3.8.
5. Allow work to proceed after deficiencies have been corrected.
6. Exercise additional delegated authority.

180.3 Primary Inspector

In the case of larger projects, additional inspection services are required beyond County provided inspection services. These inspection services are more comprehensive and intensive than County inspection services and are the responsibility of the applicant and Engineer of Record ("EOR").  In those cases, the applicant shall provide a primary inspector at their cost. 

A primary inspector's duties may be performed by a qualified representative of the engineering firm or other qualified third party inspector.  The applicant shall be responsible for primary inspection services of all improvements permitted by Engineering at no cost to the County.  A primary inspector ("PI") shall not have a corporate ownership or have real property interest in the development for which the improvements are required. 

Utility Permit work proposed by a public utility may provide qualified public utility engineering staff or a qualified third party to satisfy the requirements of a PI with the approval of Engineering.

180.3.1 Developer Engineer Agreement

When a primary inspector (PI) is required as part of a development project, the applicant shall enter into a Developer Engineer Agreement prior to Development Permit issuance to have the EOR responsible for primary inspection services.

180.3.2 Certificate of Compliance and Completion

At the completion of a project, the EOR shall be responsible for providing a Certificate of Compliance and Completion to establish that the project was completed as required by the permit.

180.3.3 When a Primary Inspector is Required

A PI is required in the following cases:

1. Development Permit: all commercial, industrial, institutional, multi-family development and residential subdivisions and partitions that will result in more than three parcels.
2. Utility Permit:
   1. More than 1,000 longitudinal feet of disturbance within the UGB.
   2. More than 2,500 longitudinal feet of disturbance outside the UGB.
   3. Night or weekend work is involved.
   4. Trench plowing
   5. Installation of a utility suspended from a bridge under County jurisdiction.
3. When a Development Permit requires a PI and an Entrance Permit is required, the PI shall assume inspection for the Entrance Permit if the Development Permit has not been finalized. 
4. Even when a PI is required, the permit is still subject to certain County inspections as dictated in the permit and herein.

180.3.4 Primary Inspector Authority and Duties

The PI shall perform the following duties:

1. Monitor construction activity and inspect work and materials furnished to ensure construction per the permit, and to reject defective materials or workmanship.
2. Provide inspection reports to the County on a weekly basis during periods of active construction. Inspection reports for each weekly period may be submitted by the end of the following week.  Confidential or sensitive material on inspection reports may be redacted.  If the reports become more than four weeks in arrears, or are significantly lacking information, the County may temporarily stop work until such time as the inspection reports are submitted.  The permit will not be closed out without receipt of inspection reports.  The inspection report shall include at a minimum:
   1. Permit number
   2. Name of inspector
   3. Date and time of arrival and departure
   4. Weather conditions, including temperature
   5. Description of construction activities
   6. Statements of direction to stop work, reject materials, or other work quality actions
   7. Perceived problems and plan of action taken
   8. Final and staged inspection results
   9. Record of all material and soil types and conditions
   10. Record of locations of cement amended base and cement amended soils within the project (these locations shall be shown on the as-built construction plans).
   11. Record of review of test results
   12. Record of review of ADA inspections
   13. Record of pavement grade and depth measurement by street stationing
   14. General remarks including citizen contact or complaints received
   15. Record of review of inspection requirements of the permit
3. Notify the County inspector two business days before the start of construction or resumption of work after shutdowns.
4. Temporarily suspend the work for lack of compliance with these Standards, land use requirements, permit conditions, plans, specifications and/or safety deficiencies.
5. Communicate critical issues to the County inspector including proposed changes, significant construction problems, property owner disputes or complaints, need for County inspections, etc. 
6. Ensure County approval prior to the commencement of work affected by any revisions.

A PI is not authorized to:

1. Revise, alter, or relax the requirements of the permit.
2. Direct how the work is to be performed.

180.4 Testing

1. All testing required by the County shall be at the applicant's expense. 
2. Testing shall be in accordance with the most recent edition of the ODOT Manual of Field Test Procedures.
3. Special testing shall be at the expense of the applicant and performed by a qualified testing firm.  The applicant shall give County inspector not less than two business days' notice prior to special testing. 
    

180.5 Required Inspections of ADA Accessibility Features

1. All ADA accessibility features within the County right of way, including but not limited to sidewalks, paths, crosswalks, curb ramps, medians, traffic islands, signs, on-street parking, and pedestrian traffic signal accessibility features including clear spaces shall be inspected for compliance with ADA requirements. No project shall be accepted as complete without documentation prepared by the County inspector showing that all ADA accessibility features meet requirements or have a previously approved exception per Section 170.2.
2. Forms Inspection - The forms inspection shall determine if the forms and survey marks for an accessibility feature are placed in such a manner to meet requirements. The contractor shall provide a signed written record of the dimensions and relative elevations of the forms for an ADA accessibility feature prior to placement of pavement using an inspection report form supplied by the County.  A diagram of the ADA accessibility feature shall be provided and at least one photo of the forms prior to fabrication. Dimensions of all sides of the accessibility feature shall be measured with a steel tape and compared with the approved design. The height of the curbs and any corners shall be determined in relation to the lowest point on the accessibility feature using a level. The completed forms inspection report provided by the contractor including diagram and photos shall be included in the project file.
3. Post fabrication inspection - The post fabrication inspection shall determine compliance of the accessibility feature with all ADA requirements. The inspection shall be conducted using the standard county inspection checklists and required measurement tools and techniques. Dimensions and curb heights shall be determined using standard methods. Slopes shall be determined using the ODOT specified 6 inch and 2 foot smart levels with multiple slope measurements taken for each feature used to determine compliance. Any element that fails to meet required PROWAG standards shall be replaced by the applicant and re-inspected for compliance. If it is determined that an ADA feature does not comply with PROWAG standards, the applicant shall have the option of appealing that determination. For the appeal the builder shall retain a Land Surveyor to conduct a survey of the ADA accessibility feature and prepare a plan showing actual elevations and slopes for the accessibility feature. If the survey plan demonstrates that the accessibility feature meets PROWAG standards the applicant will not be required to replace that accessibility feature. If the survey plan demonstrates that the accessibility feature fails to meet PROWAG standards, then the accessibility feature shall be replaced at the applicant's expense and re-inspected for compliance.

180.6 Inspection Requests

A minimum of two business days' notice shall be provided for inspection requests via the method described on the permit, which also lists the required inspections.

180.7 Failure to Obtain Inspection

If the County inspector is not able to inspect the work after proper notice, the applicant should take measures to reschedule the work.  Work that is completed without the required inspections, as dictated by the permit or as required by Section 180 is subject to rejection and/or code enforcement procedures of the County Code. 

The County inspector may pre-approve work to continue without County inspection with proper documentation provided by a primary inspector or other documentation.

170.1 Design Modifications

1. It is not the objective of these Standards to limit the creative efforts of engineers in providing alternate solutions to specific problem areas or to relieve the responsibility for professional engineering judgment. 
2. Practical design modifications that preserve the function and safety of the roadway system and offer benefits to aesthetics, resource protection, ease of maintenance, and livability are encouraged.
3. Approval of non-compliant or alternate specifications and standards under the purview of these Standards may be requested utilizing the following process.  This process does not apply to land use requirements or Conditions of Approval generated through the ZDO or the Comprehensive Plan.  The ADA exception process follows the procedures detailed below in Section 170.2. 

170.1.1 Modification Request Submittal

1. Requests to modify design standards shall utilize the Clackamas County Design Modification Request form.  Design Modifications are typically submitted prior to land use application approval or early on in the design process when related to capital construction.
2. Land use conditions of approval are commonly written so that there is little, if any, flexibility after land use approval.  For this reason, it is imperative that design modification requests be addressed prior to land use approval.  If a design modification is requested after the land use conditions of approval are issued, additional application for a modification of the conditions of approval or a new land use application through the Planning and Zoning Division may be required.

170.1.2 Criteria for Modification of Standards

The County may grant a modification when the use thereof does not compromise public safety or the intent of the County's standards and any one of the following conditions are met:

1. The subject standard is deemed not applicable in the particular circumstance.
2. Topography, right-of-way or other geographic conditions impose an environmental concern or provides a constraint for constructability and an equivalent alternative, which can accomplish the same design intent, is available.
3. A minor change to the standard and the modification is required to address a specific design or construction constraint which, if not enacted, will result in an undue hardship.
4. The proposed modification does not compromise safety, function, appearance and maintainability based upon sound engineering and technical judgment.
5. The modification is not in conflict with land use requirements.

170.1.3 Review

1. Type I modifications shall include, but not be limited to, geometric design and the modification or omission of standard roadway cross section elements.  A Type 1 modification requires a higher level of scrutiny than a Type II modification.
2. Type II modifications shall include, but not be limited to, sight distance, access spacing, number of accesses, intersection angle, etc. 
3. The request to modify design standards shall be reviewed first by Engineering technical staff who shall make one of the following decisions:
4. Approve as proposed,
5. Approve with changes, or
6. Deny with an explanation.
7. Design Modification approval shall not constitute a precedent for use at other locations.

170.1.4 Appeal

Applicants may appeal the Engineering technical staff's decision to the Transportation Engineering Manager.  The Transportation Engineering Manager's decision may be appealed to the Road Official, whose decision shall be final.

170.2 ADA Exceptions

The County has adopted the PROWAG standards for ADA accessibility within the public rights-of-way and easements under the jurisdiction of Clackamas County. PROWAG provides justifications for exceptions to the standards for new construction and for alterations to existing ADA accessibility features. Exceptions are required for any accessibility feature that cannot meet the requirements due to a physical constraint identified in the following sections.  Crosswalk closures are also reviewed under the ADA exceptions process.

170.2.1 Exceptions for New ADA Accessibility Features

Exceptions to full compliance with PROWAG standards can only be granted for a limited number of physical constraints preventing full compliance. If an exception is required for a particular feature, efforts must be made to ensure that other elements are accessible. Exceptions for non-compliance with the PROWAG standards for new ADA accessibility features can only be approved when full compliance cannot be achieved due to terrain or historic features. Where the State Historic Preservation Officer or Advisory Council on Historic Preservation determines that compliance with a requirement would threaten or destroy historically significant features of a qualified historic facility, compliance shall be required to the extent that it does not threaten or destroy historically significant features of the facility (PROWAG R202.3.4).

170.2.2 Exceptions for Alterations to Existing ADA Accessibility Features

Where existing physical constraints make it impracticable for altered facilities to fully comply with the ADA requirements, compliance is required within the scope of the project. Existing physical constraints include, but are not limited to, underlying terrain, right-of-way availability, underground structures, adjacent developed facilities, drainage, or the presence of a notable natural or historic feature (PROWAG R202.3.1). 

170.2.3 ADA Exception Request Submittal

1. Exception requests shall be submitted on the ADA Exception Request form.  Exception requests should only be submitted at the following points in the process:
2. Requests for exceptions to waive the requirement for a new ADA accessibility feature as part of a development should be submitted and acted upon prior to land use approval since land use conditions are typically written with little or no flexibility.
3. Requests for exceptions to requirements for a particular element should be submitted during plan review and must be acted upon prior to permit issuance.
4. Requests for exceptions to requirements may be submitted during construction if physical constraints are identified that were not included in the design. In such situations, the project Engineer shall prepare a revised design that maintains accessibility to the greatest extent practicable, and that exception must be acted upon prior to construction of the accessibility feature.
5. Exceptions should not be provided for noncompliant features after construction.
6. Exception requests that are submitted shall be reviewed by Engineering.  The Transportation Engineering Manager will make the decision to approve or deny the requested exception. The Transportation Engineering Manager's decision may be appealed to the Road Official, whose decision shall be final.