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Community Engagement
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Design
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Complete
Project Overview
The city's Design and Construction Standards (DCS) and Boulder Revised Code (BRC) include standards governing how transportation infrastructure must be designed and constructed in the public right-of-way.
How are these standards used?
- Private entities that build or operate public utility and transportation infrastructure in the public right-of-way in Boulder must follow these standards.
- Residents and other property owners would also have to follow the new sight triangle standards when doing certain site improvements on their property, such as replacing fencing or landscaping or when considering a new structure adjacent to the public right-of-way or public access easement.
- City staff also follow these standards for capital improvements projects.
The city is currently updating these standards to better align with current best practices and the city’s vision for a multimodal, connected transportation system, according to the city's Transportation Master Plan and Low-Stress Walk and Bike Network Plan.
Spring 2022 Community Engagement
The public feedback window has closed. Thanks to all who provided input!
Topic | Proposed Change |
---|---|
Vehicle Lane Widths |
Update lane widths table with new, narrower preferred widths to align with current best practice for constructing streets that serve people walking and bicycling. See Table 2.5 Anticipated benefit: Narrower lane widths typically yield slower vehicle speeds |
Bike Lane Widths |
Add lane widths for all expected types of bike lanes including conventional, buffered, separated, and parking-protected. See Table 2.5 Anticipated benefit: Providing standard widths for bicycle lanes will lead to more consistent projects that prioritize bicyclist safety and comfort |
Separated Bike Lanes |
Provide additional technical information about operating speed of bicyclists and the effect on design features Anticipated benefit: Providing more nuanced information about separated bike lane design will lead to more consistent design of separated bike lanes that are comfortable for bicyclists of all ages and abilities |
Corner Radii |
Update guidance and standards to help designers achieve smaller effective radii of curbs, especially through the use of curb extensions. See 2.07 (D)(5)(d) Figures 1 and 2 Anticipated benefit: Slower turning speeds and increased comfort for people walking and biking |
Road Width Tapers |
Add information about bike lane tapers in addition to existing motor vehicle lane tapers Anticipated benefit: Eliminating bike lane designs with abrupt tapers (changes in direction) that can cause rider discomfort |
Left-Turn Lanes |
Clarify goal to use a single left-turn lane first, then dual left turns if necessary. Add statement that triple left-turn lanes are only allowed with Director approval. Anticipated benefit: Reducing the number of left-turn lanes at intersections shortens crossing distances for pedestrians and bicyclists |
Topic | Proposed Change |
Separated Bike Lanes at Driveways |
Anticipated benefit: Separated bike lanes typically cross driveways and alleys. Standardizing this element of design can improve visibility of bicyclists and improve yielding compliance. |
Separated Bike Lanes at Intersections |
Anticipated benefit: The most complex aspect of separated bike lanes is at intersections. Providing examples of how to maintain safety and good sightlines through the intersection will lead to consistent design of future projects. |
Topic | Proposed Change |
Neighborhood Traffic Circles |
Anticipated benefit: Neighborhood traffic circles are a great traffic calming technique for local streets. Standardizing their design with typical dimensions will help provide consistent design of future projects. |
Raised Crossings |
Anticipated benefit: Standardizing raised crossing design will help provide consistent traffic calming and yielding compliance benefits. |
Topic | Proposed Change |
Bike Ramp Drawing |
Anticipated benefit: Provide a detailed standard for bike ramps that connect on-street bike lanes to sidewalk-level multi-use paths, providing a more comfortable and safe transition for bicyclists of all ages and abilities |
Curb Extension Drawing |
Anticipated benefit: Curb extensions help slow turning vehicles and reduce pedestrian and bicyclist crossing distances. A new standard drawing will lead to consistent design of future projects. |
Floating Bus Stop Drawing |
Anticipated benefit: Many streets proposed for separated bike lanes also have bus routes. A new standard drawing will lead to consistent design of future projects. |
Raised Crossing Drawing |
Anticipated benefit: Raised crossings slow vehicles and make pedestrians more visible. A new standard drawing will lead to consistent design of future projects. |
Multi-Use Path Section Detail Drawing |
Anticipated benefit: Noted maximum vertical clearance of 8' to match Ch. 2 text. |
Crosspan and Radii Curb Return Accesses Drawing |
Anticipated benefit: Changed minimum intersection radius from 10' to 5' to match Ch. 2 figure. |
Median Paved Curb Skirt Drawing |
Anticipated benefit: Added 4' min width for a landscaped median; added a note for 4" min depth of topsoil required to match Ch. 3 text |
Median Separated Bike Lane Drawing |
Anticipated benefit: Changed minimum separated bike lane width to 6.5' min, 7' preferred to match Ch. 2 text. |
Bicycle Path Cross-Section Drawing |
Anticipated benefit: Changed vertical clearance to 8' to match Ch. 2 text; changed max foreslope/backslope from 4:1 to 3:1; changed shoulders to earth pattern, removed on-street bike lane typical section. |
Non-Residential Street Cross-Section Example Drawings |
Update two drawings: Arterials and Collectors Anticipated benefit: Added note for designer to verify if route is on Boulder's Low Stress Walk and Bike Network, which has implications for recommended facility type between on-street bike lanes and separated bike lanes. |
Streetscape Tree Spacing and Location Drawing |
Update standard drawing to include more details about tree spacing in different streetscape contexts Anticipated benefit: Will lead to consistency in planting locations |
Streetscape Tree Spacing and Location Offset Drawing |
Add a secondary standard drawing that shows the offset distances for various amenities and utilities Anticipated benefit: Makes the offset requirements more clear visually, aiding designers in developing great landscape plans. |
Tree Grate for Sidewalk Planting Drawing |
Update drawing to include tree guard and revised tree grate detail. Modify location of amended soil. Add information on soil volume. Anticipated benefit: Provide a standard for tree plantings in urban sidewalk areas that will lead to a healthier tree thereby increasing tree canopy. |
Topic | Proposed Change |
Tree Species List |
Remove tree species references in standards text and insert reference to regularly updated tree list Anticipated benefit: Allows Boulder Forestry staff to maintain an Approved Tree List that can be updated on a regular basis to provide the best trees for the local context at any given time. |
Limitations on Individual Tree Species |
Update Tree Species table with more modern standards. Updated table Anticipated benefit: Promote tree diversity in the City of Boulder and reduce instances of monoculture plantings of trees. |
Tree Soil Volumes |
Increase minimum soil volumes Anticipated benefit: Promote healthier trees |
Streetscape Tree Spacing and Location |
Update standard drawing to include more details about tree spacing in different streetscape contexts. Updated drawing Anticipated benefit: Will lead to consistency in planting locations |
Streetscape Tree Spacing and Location |
Add a secondary standard drawing that shows the offset distances for various amenities and utilities. New drawing Anticipated benefit: Makes the offset requirements more clear visually, aiding designers in developing great landscape plans |
Tree Grate for Sidewalk Planting Drawing |
Updated drawing to include tree guard and revised tree grate detail. Modify location of amended soil. Add information on soil volume. Anticipated benefit: Provide a standard for tree plantings in urban sidewalk areas that will lead to a healthier tree thereby increasing tree canopy. |
Topic | Proposed Change |
Soil Requirements |
Updated soil definitions to match modern standards Anticipated benefit: Improvement in quality of soil and clarity on soil amendments. |
Topic | Proposed Change |
15’ x 15’ Sight Triangle |
This is not a new sight triangle. The proposed change will change the location of where the sides of the sight triangle are measured when the public street has a sidewalk. Currently the sight triangle is measured along the right-of-way line of the public street and either the right-of-way line of the public alley or the edge of the private driveway and whose third side is a line connecting the two sides. Updated figure Anticipated benefit: This change will provide staff with physical features to measure the sides of the sight triangle when responding to sight triangle complaints. |
Multi-use path intersecting either an Alley or Driveway |
This is a new 15’ x 96’ sight triangle that will be added to the sight triangle section of the Boulder Revised Code. The sides of the new multi-use path sight triangle would be 15’ x 96’ with the third side of the sight triangle being the line that connects the two sides. New figure Anticipated benefit: The 15’ x 15’ sight triangle is currently used where a multi-use path (path) intersects with either a driveway or alley. The new sight triangle increases the sight triangle area between the path and either a driveway or alley. |
Virtual Office Hours
City staff held office hours in April to answer questions related to the Transportation Design Standards Update. Thanks to all who attended!
Background
The updates to the transportation design standards are part of a larger, multi-year effort to update the city's Design and Construction Standards (DCS). A first round of community feedback on the draft transportation design standards was collected in fall 2021.
The proposed changes are designed to respond to community feedback and better align with current best practices and the city’s vision for a multimodal, connected transportation system, as reflected in Boulder’s Transportation Master Plan, Low-Stress Walk and Bike Network Plan and Forestry Strategic Plan.
The current DCS was adopted in 1998 and updated in 2000 to prescribe minimum standards to be used in the design and construction of public infrastructure located in public right-of-way and easements in the city of Boulder, as well as private transportation improvements that connect or impact public infrastructure. The DCS is enacted through the BRC and changes are adopted by City Council with recommendations from appropriate boards, such as TAB and Planning Board.