Chapter 42 City and County Design Standards for All Routes
Transcript Of Chapter 42 City and County Design Standards for All Routes
Chapter 42
City and County Design Standards for All Routes
42.1
Introduction
The City Design Standards Committee and the County Design Standards Committee, in accordance with RCW 35.78.030 and 43.32.020, meet on a regular basis to review and update the city and county design standards for all facilities (NHS and Non-NHS).
The Local Agency Engineer may approve use of the minimum AASHTO and related standards as contained in the references. Design deviations must have the approval of the Washington State Department of Transportation (WSDOT) Local Programs in accordance with RCW 35.78.040 or RCW 36.86.080 as appropriate. When AASHTO and/or related design standards as contained in the references are updated and published, agencies must incorporate the new design standards for all projects no later than two years after of the publication date.
All projects are subject to Americans with Disabilities Act (ADA) and Section 504 of the Rehabilitation Act requirements for accessibility. For guidance on ADA standards, please see Design Manual M 22-01 Chapter 1510 and the Local Agency ADA Planning and Design Resource web page at www.wsdot.wa.gov/LocalPrograms/Traffic/ada.htm.
These standards apply to new construction and reconstruction projects, 3R and 2R projects, and low volume road and street projects on all routes which are classified as Principal Arterials, Minor Arterials, or Collectors. These standards are applicable to new or reconstructed bridges on rural minor collectors, local roads, and local streets.
Included in the standards are the Local Agency Design Matrices. The matrices are used to standardize design element requirements based on project type for all facilities. The Local Agency Design Matrices Checklists may serve as design documentation for decisions made.
In adopting these standards, the committees seek to encourage standardization of road design elements where necessary for consistency and to assure that motoring, bicycling, and pedestrian public safety needs are met. Considerations include safety, convenience, context sensitive solutions, proper drainage, and economical maintenance. The committees recognize that cities and counties must have the flexibility to carry out the general duty to provide streets, roads, and highways for the diverse and changing needs of the traveling public.
These standards cannot provide for all situations. They are intended to assist, but not to substitute for, competent work by design professionals. It is expected that land surveyors, engineers, and architects will bring to each project the best skills from their respective disciplines. These standards are also not intended to limit any innovative or creative effort, which could result in better quality, better cost savings, or both. An agency may adopt higher standards to fit local conditions. Special funding programs may also have varying standards.
The decision to use a particular road design element at a particular location should be made on the basis of an engineering analysis of the location. Thus, while this document provides design standards, it is not a substitute for engineering judgment.
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Engineers should take into account all available information, including available funding, and use the professional judgment that comes from training and experience to make the final design determination. There shall be a record, of the matters considered during the design process that justify decisions made regarding the final project design. The project design must be approved by the approving authority as outlined on the agency’s Certification Acceptance Agreement or the acting designated authority for a NonCertification Acceptance agency. See Chapter 43 and Appendix 43.62.
42.2 Committee Membership
City Design Standards Committee
RCW 35.78.020
Jim Parvey, PE Senior Principal Engineer City of Tacoma [email protected]
Charles Hill, PE Senior Civil Engineer City of Puyallup [email protected]
Mike Johnson, PE Design Engineering and Construction Advisor City of Seattle [email protected]
Mike Taylor, PE City Engineer City of Spokane [email protected]
Martin Hoppe, PE, PTOE City of Lacey Transportation Manager [email protected]
Ravyn Whitewolf, PE, PMP, AVS Public Works Director City of Blaine [email protected]
County Design Standards Committee
RCW 43.32.010
Seth Walker, PE Assistant County Engineer Columbia County [email protected]
Jeff Tincher, PE County Engineer Grant County [email protected]
Mitch Reister, PE County Engineer Spokane County [email protected]
Jon Brand, PE Assistant Director of Roads and Engineering Kitsap County [email protected]
Bob McEwen, PE Program Engineer Snohomish County [email protected]
Ramiro Chavez, PE Public Works Director Thurston County [email protected]
Other Participants Alison Hellberg Association of Washington Cities [email protected]
Randy Hart, PE County Road Administration Board [email protected] Chris Workman, PE Project Engineer Transportation Improvement Board [email protected]
John Donahue WSDOT Design [email protected]@wa.gov
Megan Hall, PE Federal Highway Administration [email protected]
Mike Horton Operations Mgr. for Transportation AECOM [email protected]
These design standards were developed with the approval and authorization of:
_______________________________________ Kyle McKeon, Committee Chair Engineering Services Manager Headquarters Local Programs Washington State Department of Transportation
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42.3
Local Agency Design Matrices
The Local Agency Design Matrices were created as part of the Local Agency Standards to assist designers in determining the design level for the geometric and safety elements of a project. The Local Agency Design Matrix Checklist may serve as documentation for design decisions made.
.31 Using the Matrices – The column headings on each of the three design matrices are design elements. They are based principally on the 13 controlling design criteria recognized by FHWA: design speed, lane width, shoulder width, bridge width, structural capacity, horizontal alignment, vertical alignment, grade, stopping sight distance, cross slope, superelevation, vertical clearance, and horizontal clearance. Within the column headings, some of the controlling criteria have been combined (for example, design speed is part of horizontal and vertical alignment). The matrices are divided into three tables, one each for Roadways, Cross Roads, and Bridges. Within the three tables the project types are identical, design elements vary depending on which elements apply.
A blank cell within the design matrix signifies that the design element need not be addressed because it is beyond the scope of the project type.
Design levels of City and County Design Standards (D), AASHTO (A), and Agency Evaluate (AE), are used in the matrix. The design level codes are noted in the cells by D, A or AE or by a number corresponding to a footnote. For roads that have volumes less than 400 ADT, AASHTO Geometric Design of Very Low Volume Roads (ADT<400) may be used.
Optional Checklists have been provided for the designer to use with the matrix. A checklist is available for each type of project in Appendix 42.101.
Matrix Cells: Each Matrix cell is either blank or has a coded design level.
.32 Design Levels – If the Design Level is D, use the Geometric Cross-Section for TwoWay Roads and Streets within the City and County Design Standards on page 12.
If the design level is A, the design standard is AASHTO (the most current edition of the AASHTO publication A Policy on Geometric Design of Highway and Streets, “Guidelines for Geometric Design of Very Low-Volume Local Roads (ADT< 400),” or as noted in the City and County Design Standards. When AASHTO and/or related design standards as contained in the references are updated and published, agencies must comply with the new design standards for all projects no later than two years after of the publication date.
When the Matrix cell has either a “D” or an “A” and the final design utilizes something less than Design Level A, a Design Deviation, approved by Headquarters Local Programs, is required.
A Blank Cell on a matrix line indicates that particular design element requires no evaluation or documentation. If the agency decides to improve or modify a blank cell design element, that element must meet Design Level A and the agency must justify in their design document files why the decision to upgrade the design element was made. Per FHWA guidelines, if an improvement in a “Blank Cell” area is made, it must meet all requirements of design level A. Or if, in the opinion of the agency’s design Engineer, Design Level A cannot be achieved, a Design Exception may be considered.
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AE in a matrix cell indicates that an agency needs to determine if the existing design element is less than Design Level A. If the existing design element meets or exceeds Design Level A the agency notes that in the design documents and no further action is required. If the existing design element is less than Design Level A, the agency shall determine the impacts and cost effectiveness of upgrading the design element to Design Level A. The decision whether or not to upgrade, and its analysis and justification shall be in the agency design documentation files. If the agency upgrades, Design Level A applies. Or if, in the opinion of the agency’s design Engineer, Design Level A cannot be achieved, a Design Exception may be utilized.
A Design Exception may be utilized if, in the opinion of the local agency’s design Engineer, the existing design element is being improved but Design Level D or A cannot be achieved. For example, design standard requires a 6 foot wide shoulder for a project, the existing condition is a two foot wide shoulder but the best that can be reasonably achieved is a 4 foot wide shoulder. This is a Design Exception, improvement is being made but not to Design Level A.
Local Agency Design Matrix Definitions
.41 Design Elements – Design elements are the principal elements of design that are common to projects. The following elements are shown on the Design Matrix.
• Horizontal Alignment is the horizontal attributes of the roadway including horizontal curvature, superelevation, and stopping sight distance; all based on design speed.
• Vertical Alignment is the vertical attributes of the roadway including vertical curvature, profile grades, and stopping sight distance; all based on design speed.
• Lane Width is the distance between lane lines.
• Shoulder Width is the distance between the outside or inside edge line and the edge of in-slope, or face of barrier.
• Lane and Shoulder Taper (pavement transitions) are the rate and length of transition of changes in width of roadway surface.
• Pedestrian Facility is a facility designed to meet the needs of pedestrians in accordance with city, county, and ADA requirements concurrent with a local agency project
• Sidewalk Width is the width of a sidewalk from the face of curb to the back of sidewalk.
• Cross Slope, Lane is the rate of elevation change across a lane. This element includes the algebraic difference in cross slope between adjacent lanes.
• Cross Slope, Shoulder is the rate of elevation change across a shoulder.
• Superelevation is the rotation of the roadway cross section in such a manner as to overcome part of the centrifugal force that acts on a vehicle traversing a curve.
• Fill/Ditch Fore Slope is downward slope from edge of shoulder to bottom of ditch or catch.
• Clear Zone is the total roadside border area, starting at the edge of the traveled lane, available for use by errant vehicles. This area may consist of a shoulder, a recoverable slope, a nonrecoverable slope, and/or a clear run-out area.
• Safety Improvements are the safety items listed under the “Safety Improvements” section of these standards.
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• Shared Use Bicycle and Pedestrian Facilities are walkways, paths, or trails for shared use by both pedestrian and bicycle traffic. Effective July 1, 2012, refer to the current AASHTO bicycle design standards and/or standards submitted by the local agency which have been approved by Local Programs for any facility allowing bicycle traffic.
• Turn Radii is the geometric design of the intersection to allow the design vehicle for each turning movement to complete the turn without encroachment.
• I/S (Intersection) Sight Distance is the distance that the driver of a vehicle on the crossroad can see along the through roadway, as compared to the distance required for safe operation.
• I/S Angle is the angle between any two intersecting legs at the point that the center lines intersect.
• Barriers Standard Run (Std Run) are guardrail and other barriers excluding terminals, transitions, attenuators, and bridge rails.
• Barriers Bridge Rail is barrier on a bridge excluding transitions.
• Bridge Vertical Clearance is the minimum height between the roadway including shoulder and an overhead obstruction.
• Bridge Structural Capacity is the load bearing ability of a structure.
• Terminals are crashworthy end treatment for longitudinal barriers that is designed to reduce the potential for spearing, vaulting, rolling, or excessive deceleration of impacting vehicles from either direction of travel. Impact attenuators are considered terminals and beam guardrail terminals include anchorage.
• Transitions are sections of barriers used to produce a gradual stiffening of a flexible or semi-rigid barrier as it connects to a more rigid barrier or fixed objects.
.42 Project Type Definitions
• New Construction involves the construction of a new roadway facility or structure where nothing of its type currently exists.
• Reconstruction projects may add additional travel lanes to an existing roadway or bridge and if 50 percent or more of the project length involves vertical or horizontal alignment changes, the project will be considered reconstruction.
• 3R projects focus primarily on the preservation and extending of the service life of existing facilities and on safety enhancements. Work may include: resurfacing, pavement structural and joint repair, lane and shoulder widening, alterations to vertical grades and horizontal curves, bridge repair, removal or protection of roadside obstacles, and improving bridges to meet current standards for structural loading and to accommodate the approach roadway width.
• 2R projects focus primarily on restoration of pavement structure, crown correction, ride quality basic safety, and spot safety. Widening shoulders for continuity with the existing roadway cross section is acceptable.
• Railroad is a project to reduce the accident frequency and severity at grade crossings. Project elements may include, signals, bells, signage, pavement markings gates or surfacing at the crossing. Railroad-highway grade separation projects are also in this category. If the project includes other roadway work, use 3R matrix line.
• Bridge New/Replacement is a new bridge or a replacement of an existing bridge.
• Bridge Widening is the widening of existing bridges.
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• Bridge-Other are Project types that may include, scour mitigation, painting, seismic retrofit, deck repair, strengthening, rehabilitation, and electrical mechanical repairs.
• Paths and/or Trails is the construction of non-motorized facilities that are independent of a roadway alignment.
• Pedestrian Facilities are projects with a main focus of providing pedestrian facilities for public use.
• Other, Interpretive Centers, Etc. projects may include, bicycle facilities, structures, bus shelters, archeology and historic preservation, and buildings.
• Parking Facilities are projects that construct parking facilities. Project types may include Park and Ride facilities and on-street parking.
.43 Other Definitions • Average Daily Traffic (ADT) – The general unit of measure for traffic defined as the total volume during a given time period (in whole days), greater than one day and less than one year, divided by the number of days in that time period. • Design Hourly Volume (DHV) – The DHV is generally the 30th highest hourly volume (30 DHV) of the future year chosen for design. On the average rural road or arterial, DHV is about 15 percent of ADT. For urban areas, DHV is usually between 8 to 12 percent of the ADT. • Low Volume Roads and Streets – For this document, a collector or lower classified road or street with an ADT of less than 400. • Resurfacing – The addition of a layer or layers of paving material to provide additional structural integrity or improved serviceability and rideability. • Restoration – Work performed on either pavement sections or bridge decks to render them suitable for an additional stage of construction. This may include supplementing the existing roadway by increasing surfacing and paving courses to provide structural capability and minor shoulder widening to provide roadway section continuity. Restoration will generally be performed within the existing right of way. • Rehabilitation – Similar to “Restoration” except the work may include, but is not limited to, the following: – Reworking, strengthening, or removing and replacing the base and/or subgrade. – Recycling or reworking existing materials to improve their structural integrity. – Adding underdrains. – Replacing or restoring malfunctioning joints. – Substantial pavement under-sealing when essential for stabilization. – Pavement grinding to restore smoothness, providing adequate structural thickness remains. – Removing and replacing deteriorated materials. – Crack and joint sealing but only when the required shape factor is established by routing or sawing. – Improving or widening shoulders.
Rehabilitation may require acquisitions of additional right of way. • Traveled Lane – The portion of the roadway intended for the movement of vehicles,
exclusive of shoulders and lanes for parking, turning, and storage for turning.
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.044 Safety Improvements – When using AASHTO guidance for clear zone determinations, the designer should take into account all AASHTO guidance (i.e., AASHTO Roadside Design Guide) relating to clear zone and project circumstances. See references section of this chapter.
Mandatory Upgrades
1. Update all delineation and signing in accordance with the current MUTCD. (This does not include replacement of sign bridges or cantilever supports.)
2. Modify substandard guardrail transitions and terminals to current standards.
Agency Evaluate Need
3. Adjust existing features that are affected by resurfacing, such as guardrails, monuments, catch basins, and access covers. Adjustment may include asphalt tapers as appropriate.
4. Modification of drainage structures, which present a hazard in the clear zone, e.g., beveled end sections/safety bars for both parallel and cross-drains.
5. Remove, relocate, reduce severity of hazard by providing crashworthy features, protect, or delineate roadside obstacles inside the design clear zone.
6. Restore sight distance at public road intersections and the inside of curves through low cost measures if they are available such as removal or relocation of signs and other obstructions, and cutting of vegetative matter. The local agency Engineer will determine if the measures are low cost.
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Project Type
Roadways
Design Elements
New Construction
Lane &
Cross Cross Fill/
Shared
Horiz. Vert. Lane Shldr Shldr Pedestrian Slope Slope Ditch
Safety
Bike/Ped
Align. Align. Width Width Taper Facilities Lane Shldr Slopes Improvements Facilities
D
D
D
D
D
1
D
D
D
A
1
Turn Radii
A
I/S Sight Dist
D
I/S Guardrail Angle & Barrier
A
A
Re-Construction
A
A
A
A
A
1
A
A
A
A
1
A
A
A
A
3R
AE AE AE AE AE
1
AE AE AE
2
1
AE AE AE
1
2R
AE AE
2
Railroad (If rinocalduwdeady,wuosrek3R AE line)
Bridge RPaeihnat,bSilietaistimonic,, Scour, etc.
Trails
1
1
1
1
1
1
1
1
Pedestrian Facility
Improvement
1
Projects
OCethneter,rsIn,teetrcp.retive 1 1 1 1 1 1 1 1 1 A
Parking Facilities A
A
A
A
A
1
A
A
A
A
1
1
1
AE
1
1
1
1
1
1
1
1
1
1
1
A
A
A
1
D Design Level D A Design Level A AE Agency Evaluate to Design Level A
1. When provided, must meet current applicable standards. 2. Refer to Safety Improvements on page 7. Mandatory Upgrade items 1 and all others are AE.
City and County Design Standards for All Routes
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Local Agency Design Matrix Table 1.1
City and County Design Standards for All Routes
Chapter 42
ò Project Type
Design Elements New Construction Re-Construction 3R 2R Railroad (If roadway work included, use 3R line) Bridge Rehabilitation, Paint, Seismic, etc. Trails Pedestrian Facility Improvement Projects Other, Interpretive Centers, etc. Parking Facilities
Horiz. Align AE AE AE
1 A
Vert. Align AE AE AE
1 A
Lane Width
AE AE AE
1 A
Cross Roads
Shldr Width
Fill/ Ditch Slopes
AE
AE
AE
AE
AE
AE
1
1
A
A
Safety Improve-
ments 2 2 2
1 1
Shared Bike/Ped Facilities
1 1 1 1
1 1
D Design Level D A Design Level A AE Agency Evaluate to Design Level A
1. When provided, must meet current standards.
2. Refer to Safety Improvements on page 7. Mandatory Upgrade items 1 and all others are AE.
Local Agency Design Matrix Table 1.2
ò Project Type
Design Elements ð New Construction Re-Construction 3R 2R Railroad (If roadway work included, use 3R line) Bridge Rehabilitation, Paint, Seismic, etc. Trails Pedestrian Facility Improvement Projects Other, Interpretive Centers, etc. Parking Facilities
Lane Width
D A AE
1
1 A
Shldr Width
D A AE
1
1 A
Local Agency Design Matrix Table 1.3
Bridges Vertical Clearance
D D AE AE
Structural Capacity
D D AE AE
Bridge Rail
D D 1 1 1
1
1
1
1
1
1
AE
AE
1
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Cross Section
WSDOT Local Agency Guidelines M 36-63.40 June 2021
City and County Design Standards for All Routes
42.1
Introduction
The City Design Standards Committee and the County Design Standards Committee, in accordance with RCW 35.78.030 and 43.32.020, meet on a regular basis to review and update the city and county design standards for all facilities (NHS and Non-NHS).
The Local Agency Engineer may approve use of the minimum AASHTO and related standards as contained in the references. Design deviations must have the approval of the Washington State Department of Transportation (WSDOT) Local Programs in accordance with RCW 35.78.040 or RCW 36.86.080 as appropriate. When AASHTO and/or related design standards as contained in the references are updated and published, agencies must incorporate the new design standards for all projects no later than two years after of the publication date.
All projects are subject to Americans with Disabilities Act (ADA) and Section 504 of the Rehabilitation Act requirements for accessibility. For guidance on ADA standards, please see Design Manual M 22-01 Chapter 1510 and the Local Agency ADA Planning and Design Resource web page at www.wsdot.wa.gov/LocalPrograms/Traffic/ada.htm.
These standards apply to new construction and reconstruction projects, 3R and 2R projects, and low volume road and street projects on all routes which are classified as Principal Arterials, Minor Arterials, or Collectors. These standards are applicable to new or reconstructed bridges on rural minor collectors, local roads, and local streets.
Included in the standards are the Local Agency Design Matrices. The matrices are used to standardize design element requirements based on project type for all facilities. The Local Agency Design Matrices Checklists may serve as design documentation for decisions made.
In adopting these standards, the committees seek to encourage standardization of road design elements where necessary for consistency and to assure that motoring, bicycling, and pedestrian public safety needs are met. Considerations include safety, convenience, context sensitive solutions, proper drainage, and economical maintenance. The committees recognize that cities and counties must have the flexibility to carry out the general duty to provide streets, roads, and highways for the diverse and changing needs of the traveling public.
These standards cannot provide for all situations. They are intended to assist, but not to substitute for, competent work by design professionals. It is expected that land surveyors, engineers, and architects will bring to each project the best skills from their respective disciplines. These standards are also not intended to limit any innovative or creative effort, which could result in better quality, better cost savings, or both. An agency may adopt higher standards to fit local conditions. Special funding programs may also have varying standards.
The decision to use a particular road design element at a particular location should be made on the basis of an engineering analysis of the location. Thus, while this document provides design standards, it is not a substitute for engineering judgment.
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Engineers should take into account all available information, including available funding, and use the professional judgment that comes from training and experience to make the final design determination. There shall be a record, of the matters considered during the design process that justify decisions made regarding the final project design. The project design must be approved by the approving authority as outlined on the agency’s Certification Acceptance Agreement or the acting designated authority for a NonCertification Acceptance agency. See Chapter 43 and Appendix 43.62.
42.2 Committee Membership
City Design Standards Committee
RCW 35.78.020
Jim Parvey, PE Senior Principal Engineer City of Tacoma [email protected]
Charles Hill, PE Senior Civil Engineer City of Puyallup [email protected]
Mike Johnson, PE Design Engineering and Construction Advisor City of Seattle [email protected]
Mike Taylor, PE City Engineer City of Spokane [email protected]
Martin Hoppe, PE, PTOE City of Lacey Transportation Manager [email protected]
Ravyn Whitewolf, PE, PMP, AVS Public Works Director City of Blaine [email protected]
County Design Standards Committee
RCW 43.32.010
Seth Walker, PE Assistant County Engineer Columbia County [email protected]
Jeff Tincher, PE County Engineer Grant County [email protected]
Mitch Reister, PE County Engineer Spokane County [email protected]
Jon Brand, PE Assistant Director of Roads and Engineering Kitsap County [email protected]
Bob McEwen, PE Program Engineer Snohomish County [email protected]
Ramiro Chavez, PE Public Works Director Thurston County [email protected]
Other Participants Alison Hellberg Association of Washington Cities [email protected]
Randy Hart, PE County Road Administration Board [email protected] Chris Workman, PE Project Engineer Transportation Improvement Board [email protected]
John Donahue WSDOT Design [email protected]@wa.gov
Megan Hall, PE Federal Highway Administration [email protected]
Mike Horton Operations Mgr. for Transportation AECOM [email protected]
These design standards were developed with the approval and authorization of:
_______________________________________ Kyle McKeon, Committee Chair Engineering Services Manager Headquarters Local Programs Washington State Department of Transportation
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42.3
Local Agency Design Matrices
The Local Agency Design Matrices were created as part of the Local Agency Standards to assist designers in determining the design level for the geometric and safety elements of a project. The Local Agency Design Matrix Checklist may serve as documentation for design decisions made.
.31 Using the Matrices – The column headings on each of the three design matrices are design elements. They are based principally on the 13 controlling design criteria recognized by FHWA: design speed, lane width, shoulder width, bridge width, structural capacity, horizontal alignment, vertical alignment, grade, stopping sight distance, cross slope, superelevation, vertical clearance, and horizontal clearance. Within the column headings, some of the controlling criteria have been combined (for example, design speed is part of horizontal and vertical alignment). The matrices are divided into three tables, one each for Roadways, Cross Roads, and Bridges. Within the three tables the project types are identical, design elements vary depending on which elements apply.
A blank cell within the design matrix signifies that the design element need not be addressed because it is beyond the scope of the project type.
Design levels of City and County Design Standards (D), AASHTO (A), and Agency Evaluate (AE), are used in the matrix. The design level codes are noted in the cells by D, A or AE or by a number corresponding to a footnote. For roads that have volumes less than 400 ADT, AASHTO Geometric Design of Very Low Volume Roads (ADT<400) may be used.
Optional Checklists have been provided for the designer to use with the matrix. A checklist is available for each type of project in Appendix 42.101.
Matrix Cells: Each Matrix cell is either blank or has a coded design level.
.32 Design Levels – If the Design Level is D, use the Geometric Cross-Section for TwoWay Roads and Streets within the City and County Design Standards on page 12.
If the design level is A, the design standard is AASHTO (the most current edition of the AASHTO publication A Policy on Geometric Design of Highway and Streets, “Guidelines for Geometric Design of Very Low-Volume Local Roads (ADT< 400),” or as noted in the City and County Design Standards. When AASHTO and/or related design standards as contained in the references are updated and published, agencies must comply with the new design standards for all projects no later than two years after of the publication date.
When the Matrix cell has either a “D” or an “A” and the final design utilizes something less than Design Level A, a Design Deviation, approved by Headquarters Local Programs, is required.
A Blank Cell on a matrix line indicates that particular design element requires no evaluation or documentation. If the agency decides to improve or modify a blank cell design element, that element must meet Design Level A and the agency must justify in their design document files why the decision to upgrade the design element was made. Per FHWA guidelines, if an improvement in a “Blank Cell” area is made, it must meet all requirements of design level A. Or if, in the opinion of the agency’s design Engineer, Design Level A cannot be achieved, a Design Exception may be considered.
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42.4
AE in a matrix cell indicates that an agency needs to determine if the existing design element is less than Design Level A. If the existing design element meets or exceeds Design Level A the agency notes that in the design documents and no further action is required. If the existing design element is less than Design Level A, the agency shall determine the impacts and cost effectiveness of upgrading the design element to Design Level A. The decision whether or not to upgrade, and its analysis and justification shall be in the agency design documentation files. If the agency upgrades, Design Level A applies. Or if, in the opinion of the agency’s design Engineer, Design Level A cannot be achieved, a Design Exception may be utilized.
A Design Exception may be utilized if, in the opinion of the local agency’s design Engineer, the existing design element is being improved but Design Level D or A cannot be achieved. For example, design standard requires a 6 foot wide shoulder for a project, the existing condition is a two foot wide shoulder but the best that can be reasonably achieved is a 4 foot wide shoulder. This is a Design Exception, improvement is being made but not to Design Level A.
Local Agency Design Matrix Definitions
.41 Design Elements – Design elements are the principal elements of design that are common to projects. The following elements are shown on the Design Matrix.
• Horizontal Alignment is the horizontal attributes of the roadway including horizontal curvature, superelevation, and stopping sight distance; all based on design speed.
• Vertical Alignment is the vertical attributes of the roadway including vertical curvature, profile grades, and stopping sight distance; all based on design speed.
• Lane Width is the distance between lane lines.
• Shoulder Width is the distance between the outside or inside edge line and the edge of in-slope, or face of barrier.
• Lane and Shoulder Taper (pavement transitions) are the rate and length of transition of changes in width of roadway surface.
• Pedestrian Facility is a facility designed to meet the needs of pedestrians in accordance with city, county, and ADA requirements concurrent with a local agency project
• Sidewalk Width is the width of a sidewalk from the face of curb to the back of sidewalk.
• Cross Slope, Lane is the rate of elevation change across a lane. This element includes the algebraic difference in cross slope between adjacent lanes.
• Cross Slope, Shoulder is the rate of elevation change across a shoulder.
• Superelevation is the rotation of the roadway cross section in such a manner as to overcome part of the centrifugal force that acts on a vehicle traversing a curve.
• Fill/Ditch Fore Slope is downward slope from edge of shoulder to bottom of ditch or catch.
• Clear Zone is the total roadside border area, starting at the edge of the traveled lane, available for use by errant vehicles. This area may consist of a shoulder, a recoverable slope, a nonrecoverable slope, and/or a clear run-out area.
• Safety Improvements are the safety items listed under the “Safety Improvements” section of these standards.
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• Shared Use Bicycle and Pedestrian Facilities are walkways, paths, or trails for shared use by both pedestrian and bicycle traffic. Effective July 1, 2012, refer to the current AASHTO bicycle design standards and/or standards submitted by the local agency which have been approved by Local Programs for any facility allowing bicycle traffic.
• Turn Radii is the geometric design of the intersection to allow the design vehicle for each turning movement to complete the turn without encroachment.
• I/S (Intersection) Sight Distance is the distance that the driver of a vehicle on the crossroad can see along the through roadway, as compared to the distance required for safe operation.
• I/S Angle is the angle between any two intersecting legs at the point that the center lines intersect.
• Barriers Standard Run (Std Run) are guardrail and other barriers excluding terminals, transitions, attenuators, and bridge rails.
• Barriers Bridge Rail is barrier on a bridge excluding transitions.
• Bridge Vertical Clearance is the minimum height between the roadway including shoulder and an overhead obstruction.
• Bridge Structural Capacity is the load bearing ability of a structure.
• Terminals are crashworthy end treatment for longitudinal barriers that is designed to reduce the potential for spearing, vaulting, rolling, or excessive deceleration of impacting vehicles from either direction of travel. Impact attenuators are considered terminals and beam guardrail terminals include anchorage.
• Transitions are sections of barriers used to produce a gradual stiffening of a flexible or semi-rigid barrier as it connects to a more rigid barrier or fixed objects.
.42 Project Type Definitions
• New Construction involves the construction of a new roadway facility or structure where nothing of its type currently exists.
• Reconstruction projects may add additional travel lanes to an existing roadway or bridge and if 50 percent or more of the project length involves vertical or horizontal alignment changes, the project will be considered reconstruction.
• 3R projects focus primarily on the preservation and extending of the service life of existing facilities and on safety enhancements. Work may include: resurfacing, pavement structural and joint repair, lane and shoulder widening, alterations to vertical grades and horizontal curves, bridge repair, removal or protection of roadside obstacles, and improving bridges to meet current standards for structural loading and to accommodate the approach roadway width.
• 2R projects focus primarily on restoration of pavement structure, crown correction, ride quality basic safety, and spot safety. Widening shoulders for continuity with the existing roadway cross section is acceptable.
• Railroad is a project to reduce the accident frequency and severity at grade crossings. Project elements may include, signals, bells, signage, pavement markings gates or surfacing at the crossing. Railroad-highway grade separation projects are also in this category. If the project includes other roadway work, use 3R matrix line.
• Bridge New/Replacement is a new bridge or a replacement of an existing bridge.
• Bridge Widening is the widening of existing bridges.
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City and County Design Standards for All Routes
• Bridge-Other are Project types that may include, scour mitigation, painting, seismic retrofit, deck repair, strengthening, rehabilitation, and electrical mechanical repairs.
• Paths and/or Trails is the construction of non-motorized facilities that are independent of a roadway alignment.
• Pedestrian Facilities are projects with a main focus of providing pedestrian facilities for public use.
• Other, Interpretive Centers, Etc. projects may include, bicycle facilities, structures, bus shelters, archeology and historic preservation, and buildings.
• Parking Facilities are projects that construct parking facilities. Project types may include Park and Ride facilities and on-street parking.
.43 Other Definitions • Average Daily Traffic (ADT) – The general unit of measure for traffic defined as the total volume during a given time period (in whole days), greater than one day and less than one year, divided by the number of days in that time period. • Design Hourly Volume (DHV) – The DHV is generally the 30th highest hourly volume (30 DHV) of the future year chosen for design. On the average rural road or arterial, DHV is about 15 percent of ADT. For urban areas, DHV is usually between 8 to 12 percent of the ADT. • Low Volume Roads and Streets – For this document, a collector or lower classified road or street with an ADT of less than 400. • Resurfacing – The addition of a layer or layers of paving material to provide additional structural integrity or improved serviceability and rideability. • Restoration – Work performed on either pavement sections or bridge decks to render them suitable for an additional stage of construction. This may include supplementing the existing roadway by increasing surfacing and paving courses to provide structural capability and minor shoulder widening to provide roadway section continuity. Restoration will generally be performed within the existing right of way. • Rehabilitation – Similar to “Restoration” except the work may include, but is not limited to, the following: – Reworking, strengthening, or removing and replacing the base and/or subgrade. – Recycling or reworking existing materials to improve their structural integrity. – Adding underdrains. – Replacing or restoring malfunctioning joints. – Substantial pavement under-sealing when essential for stabilization. – Pavement grinding to restore smoothness, providing adequate structural thickness remains. – Removing and replacing deteriorated materials. – Crack and joint sealing but only when the required shape factor is established by routing or sawing. – Improving or widening shoulders.
Rehabilitation may require acquisitions of additional right of way. • Traveled Lane – The portion of the roadway intended for the movement of vehicles,
exclusive of shoulders and lanes for parking, turning, and storage for turning.
WSDOT Local Agency Guidelines M 36-63.40 June 2021
City and County Design Standards for All Routes
Chapter 42
.044 Safety Improvements – When using AASHTO guidance for clear zone determinations, the designer should take into account all AASHTO guidance (i.e., AASHTO Roadside Design Guide) relating to clear zone and project circumstances. See references section of this chapter.
Mandatory Upgrades
1. Update all delineation and signing in accordance with the current MUTCD. (This does not include replacement of sign bridges or cantilever supports.)
2. Modify substandard guardrail transitions and terminals to current standards.
Agency Evaluate Need
3. Adjust existing features that are affected by resurfacing, such as guardrails, monuments, catch basins, and access covers. Adjustment may include asphalt tapers as appropriate.
4. Modification of drainage structures, which present a hazard in the clear zone, e.g., beveled end sections/safety bars for both parallel and cross-drains.
5. Remove, relocate, reduce severity of hazard by providing crashworthy features, protect, or delineate roadside obstacles inside the design clear zone.
6. Restore sight distance at public road intersections and the inside of curves through low cost measures if they are available such as removal or relocation of signs and other obstructions, and cutting of vegetative matter. The local agency Engineer will determine if the measures are low cost.
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Project Type
Roadways
Design Elements
New Construction
Lane &
Cross Cross Fill/
Shared
Horiz. Vert. Lane Shldr Shldr Pedestrian Slope Slope Ditch
Safety
Bike/Ped
Align. Align. Width Width Taper Facilities Lane Shldr Slopes Improvements Facilities
D
D
D
D
D
1
D
D
D
A
1
Turn Radii
A
I/S Sight Dist
D
I/S Guardrail Angle & Barrier
A
A
Re-Construction
A
A
A
A
A
1
A
A
A
A
1
A
A
A
A
3R
AE AE AE AE AE
1
AE AE AE
2
1
AE AE AE
1
2R
AE AE
2
Railroad (If rinocalduwdeady,wuosrek3R AE line)
Bridge RPaeihnat,bSilietaistimonic,, Scour, etc.
Trails
1
1
1
1
1
1
1
1
Pedestrian Facility
Improvement
1
Projects
OCethneter,rsIn,teetrcp.retive 1 1 1 1 1 1 1 1 1 A
Parking Facilities A
A
A
A
A
1
A
A
A
A
1
1
1
AE
1
1
1
1
1
1
1
1
1
1
1
A
A
A
1
D Design Level D A Design Level A AE Agency Evaluate to Design Level A
1. When provided, must meet current applicable standards. 2. Refer to Safety Improvements on page 7. Mandatory Upgrade items 1 and all others are AE.
City and County Design Standards for All Routes
WSDOT Local Agency Guidelines M 36-63.40 June 2021
Local Agency Design Matrix Table 1.1
City and County Design Standards for All Routes
Chapter 42
ò Project Type
Design Elements New Construction Re-Construction 3R 2R Railroad (If roadway work included, use 3R line) Bridge Rehabilitation, Paint, Seismic, etc. Trails Pedestrian Facility Improvement Projects Other, Interpretive Centers, etc. Parking Facilities
Horiz. Align AE AE AE
1 A
Vert. Align AE AE AE
1 A
Lane Width
AE AE AE
1 A
Cross Roads
Shldr Width
Fill/ Ditch Slopes
AE
AE
AE
AE
AE
AE
1
1
A
A
Safety Improve-
ments 2 2 2
1 1
Shared Bike/Ped Facilities
1 1 1 1
1 1
D Design Level D A Design Level A AE Agency Evaluate to Design Level A
1. When provided, must meet current standards.
2. Refer to Safety Improvements on page 7. Mandatory Upgrade items 1 and all others are AE.
Local Agency Design Matrix Table 1.2
ò Project Type
Design Elements ð New Construction Re-Construction 3R 2R Railroad (If roadway work included, use 3R line) Bridge Rehabilitation, Paint, Seismic, etc. Trails Pedestrian Facility Improvement Projects Other, Interpretive Centers, etc. Parking Facilities
Lane Width
D A AE
1
1 A
Shldr Width
D A AE
1
1 A
Local Agency Design Matrix Table 1.3
Bridges Vertical Clearance
D D AE AE
Structural Capacity
D D AE AE
Bridge Rail
D D 1 1 1
1
1
1
1
1
1
AE
AE
1
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City and County Design Standards for All Routes
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Cross Section
WSDOT Local Agency Guidelines M 36-63.40 June 2021