This is an alternative web-accessible version to the original Boulder Speed Limit Setting Framework PDF.

1. Background

The City of Boulder’s Transportation and Mobility Department has undertaken this project to develop a data-driven and context-sensitive process to set speed limits on city-owned streets. The project establishes a consistent framework for setting and communicating speed limits citywide with the aim to reduce speed-related crashes as part of Vision Zero, Boulder’s goal to end severe crashes. The 2022 Vision Zero Boulder: Safe Streets Report identified speeding as an over-represented factor, associated with nearly one-third of serious injury and fatal crashes in the 3-year time period (2018-2020). Public feedback for the 2023 Vison Zero Action Plan listed speeding as one of the Top 4 traffic safety concerns, and high-speed streets are identified as one of the Top 6 risk factors associated with the city’s High Risk Network. Action 7 was identified in the Plan to “Update and implement Boulder’s policies and practices regarding speed limit setting to better align target and actual operating speeds”. This project is one of many components the City of Boulder is exploring to reduce speeding-related crashes and improve safety for all roadway users.

Speed-related goals in the Boulder Vision Zero Action Plan:

  • Update and implement Boulder’s policies and practices regarding speed limit setting to better align target and actual operating speeds.
    • STATUS: Addressed through this project.
  • Strategically deploy photo radar van along highspeed corridors where allowed by state law
    • STATUS: Resolution adopted in December 2023 designating corridors where the city plans to expand photo enforcement.
  • Support legislation to enable expanded use of photo radar van (commercial settings, higher speed streets) and red light cameras.
    • STATUS: Statewide legislation legalizing photo enforcement passed in 2023

2. Project Purpose

The prevailing speed limit setting and signing practices in Boulder have led to inconsistent outcomes lacking quantifiable justification. The historic practice was reactive to community concerns. The goal of these guidelines is to improve consistency and develop a standard methodology behind speed limit setting and signing by establishing a data-driven citywide approach and practice. The purpose of this report is to create a transparent document to share this methodology with the community and stakeholders.

  • CONSISTENCY: Develop a methodology that leads to speed limits that are consistent with the character of the street, as well as other streets across the city with a similar character.
  • DATA-DRIVEN: Establish a quantitative process that relies on a variety of factors, including crash history, collected speeds, latest roadway geometry, user experience, and land-use data.
  • SAFETY CENTRIC: Prioritize speed-related and vulnerable user crashes in the methodology.
  • BICYCLE AND PEDESTRIAN ACTIVITY FOCUSED: Incorporate level of bicycle and pedestrian activity on the street and presence and type of pedestrian and bicycle facilities to determine the posted speed limit

3. Boulder Context

There are approximately 292 miles of city-owned streets within Boulder that are classified as local, collector, minor arterial and principal arterial (Figure 1). A vast majority, 78% of these streets are classified as local streets (Figure 2). The 20 IS PLENTY initiative established a standard 20 mph speed limit on these streets whether or not there is a posted speed limit sign or not. As such, this project aims to establish a process to set speed limits with a focus on collector and arterial roadways. Of the remaining 66 miles of collectors and arterials, the vast majority are posted at 35 mph or less (Figure 3). Of collectors, almost 58% are posted at 25 mph. Minor arterial and principal arterial streets generally have higher posted speed limits compared to collectors.

Figure 1: Functional Classification of City-Owned Streets

Figure 1 map of Functional Classification of City-Owned Streets. Long description under header Text Alternatives.

Figure 2: Functional Classification Distribution by Miles

A pie chart shows the distribution of Boulder street classifications. 78% of lane miles are local streets, 10% are collectors, 8% are minor arterials, and 4% are principal arterials.

Figure 3: Current Distribution of Speed Limits by Functional Classification

Figure 3 of Current Distribution of Speed Limits by Functional Classification. Long description under header Text Alternatives.

Land-use plays a vital role in determining roadway characteristics, which in turn impacts the speed limit of the street. This project analyzed existing zoning classifications within the Boulder Municipal Code to categorize the zoning into four land uses: downtown, residential/mixed-use/public, business and industrial/agricultural (Figure 4). The speed limit setting methodology takes into consideration these existing land-uses on either side of the street.

Figure 4: Land Use Categories

Figure 4 map of Land Use Categories. Long description under header Text Alternatives.

Residential/mixed use land-use covers approximately 78% of Boulder’s land area, which corresponds with approximately 69% of street segments analyzed in the project (Figure 5). Industrial/agricultural, downtown and business land-use coverage generally aligns with the mileage of the street segments analyzed in the project, as shown in the figure below.

Figure 5: Land Use Coverage and Street Segments

Figure 5 chart of land use Coverage and Street Segments. Long description under header Text Alternatives.

The existing posted speed limit range for any particular functional classification of roadway varies significantly across the land-uses (Table 1). For example, a collector in residential/mixed use area currently has a posted speed limit as high as 40 mph, while a collector in an industrial/agricultural land use has a maximum posted speed limit of 35 mph. Similarly, a principal arterial in downtown has a 30 mph speed limit, while it is as low as 25 mph in the residential / mixed-use area. These examples illustrate the inconsistency of existing posted speed limits in Boulder.

Table 1: Existing Posted Speed Limit Ranges in Various Land-Use

Existing ConditionsZoning Classifications per 9-5-2.a of Boulder Municipal Code
Downtown Residential / Mixed Use / Public Business Industrial Agricultural
Collector Speed Limit25-2525-4025-2525-35
Minor Arterial Speed Limit20-2520-4030-3530-45
Principal Arterial Speed Limit30-30 25-4030-3535-45

4. Stakeholder Engagement

The following stakeholders were involved throughout the project. They provided guidance for the project, offering their lived experiences of Boulder’s transportation system and community perspective to inform the project process in alignment with the overall goals of the project.

  • Transportation Advisory Board
  • Community Cycles
  • Center For People with Disabilities
  • Boulder Chamber

Three stakeholder meetings were conducted during the course of the project. The following section provides a summary of the meetings and resulting outcomes.

Stakeholder Meeting #1: August 10th, 2023

The purpose of the meeting was to introduce the project goals to the stakeholders, discuss anticipated outcomes, and identify key issues to be addressed by the project. The introduction of the project background, purpose and goals resulted in several discussion points with the stakeholders that led to the following clarifying points:

  • 85th-percentile speed has historically been used in the industry as the primary input to setting speed limits. This project intends to utilize the 85th-percentile speeds but does not intend for that to be the primary factor.
  • CDOT owned roads are not included in the analysis. However, the proposed methodology reviewed and incorporated certain elements of the framework used by CDOT in setting speed limits.
  • This project does not focus on enforcement strategies or tools. However, it is acknowledged that these tools are important to ensure compliance with the posted speed limit.

Stakeholder Meeting #2: October 3rd, 2023

The purpose of this meeting was to educate stakeholders on the national best practices, summarize peer agency approaches to speed limit setting and brainstorm factors to include in the methodology for Boulder. The summary of the outcomes were:

  • Latest national best practices allow the use of 50th-percentile speed, which is the median (average) speed of existing vehicles on the road.
  • Peer cities use a variety of methods that rely heavily on local context and engineering judgement, while also utilizing national tools like USLIMITS2.
  • A variety of factors were brainstormed for use in determining the speed limit on the roadway. These factors were categorized into roadway geometry, traffic operations, and land-use context.

Stakeholder Meeting #3: February 7th, 2024

The purpose of this meeting was to review the draft methodology for setting speed limits in Boulder, along with a few of the preliminary recommended speed limits. The examples of speed limit changes recommended by the methodology on particular streets helped the stakeholders understand the process. The stakeholders were generally, supportive of the overall methodology. Stakeholders raised questions about how often the street segments will be re-evaluated in the future, and the need for further refinement of the methodology. The project team communicated that Boulder is anticipated to re-evaluate the street segments when there is significant change in the roadway characteristics, such as when a capital improvement project or new development is completed, and noted that Boulder staff has reviewed the methodology in detail and plan to further refine it, if necessary, in the future.

5. National Best Practices

Seven documents were reviewed by the project team to understand nationally recognized best practices: the Manual of Uniform Traffic Control Devices (MUTCD) from 2009 and 2023; the Institute of Transportation Engineers (ITE) Speed Management for Safety Tools; FHWA’s Noteworthy Speed Management Practices; the National Association of City Transportation Officials (NACTO) City Limits Document; FHWA’s USLimits2; and the National Cooperative Highway Research Program Posted Speed Limit Setting Procedure Tool.

The key takeaway from this review is that the transportation profession has broadened the range of operating speeds that can be used to determine posted speed limits from the 85th-percentile, as stated in the 2009 MUTCD, to 50th-percentile and 85th-percentile speed, as stated in the 2023 MUTCD. This change allows jurisdictions the flexibility to reduce posted speeds to the median speed of vehicles traveling on the roadway. Furthermore, the review confirms the roadway contextual factors to consider when setting speed limits. These factors were reviewed and considered to determine the recommended factors that were incorporated into the city’s methodology.

VI. Peer Agency Review

Figure 6: Peer Cities Reviewed

A map of the United States highlights peer cities reviewed: Seattle, WA, Davis, CA, Denver, CO, Austin, TX, Madison, WI, and Charlotte, NC.

Six cities, shown on the map in Figure 6, were interviewed to better understand how they set their speed limits. The cities were Austin, TX; Charlotte, NC; Madison, WI; Seattle, WA; Davis, CA; and Denver, CO. Key takeaways from the peer cities review highlight the significant role of the local authority and engineering judgment in determining speed limit regulations. The approach to speed management varied, ranging from corridor-specific adjustments to city-wide initiatives, albeit often influenced by resource constraints. Methodologies employed encompass a spectrum from engineering judgment to national tools, or the creation of customized approaches. In response, this project aims to craft a tailored methodology, drawing from national tools and best practices. In addition to peer cities, Colorado Department of Transportation (CDOT) guidelines were evaluated. CDOT is currently working on its own speed limit setting methodology, which will be used to set speeds on state highways across the state. While Boulder doesn’t have authority to set speed limits on state highways, reviewing CDOT’s methodology provided the framework for the Boulder’s methodology and the opportunity to build on it. The CDOT process uses a Lookup Table based on roadway classification and land use, which is also used in the Boulder methodology with local context-sensitive information.

7. Methodology

City of Boulder’s pioneering approach to citywide speed limit setting considered the national best practices and peer agency reviews discussed above, along with input from the stakeholder committee to identify the factors that should be considered in a speed limit setting analysis and an innovative point-based system that prioritized the factors and assigned them to the segments based on segment-specific data. Figure 7 shows the overall project approach used in the project.

Figure 7: Overall Project Approach

Project approach; long description in caption.

View full image.
This is a text alternative to the image: The project’s methodology included 5 main steps. First, a review of best practices and peer agencies was conducted, which included USLIMITS 2, National Cooperative Highway Research Program (NCHRP), and Colorado Department of Transportation guidance, 6 peer cities, and 240 data collection locations. Then, through a review of methodology factors with stakeholders and a workshop on data availability and quality, 16 factors were selected for analysis out of 19 total and the selected factors were divided into tiers based on priority. Next, a point system was developed based on the priority of factors, where speed-related crashes and vulnerable user data were analyzed to quantify the need for lower speeds. Then, speed limit ranges and outputs were compared to street classification and surrounding land use. Finally, an implementation plan was developed based on the city’s capacity and programs.  

This proposed methodology applies to collector, minor arterial, and principal arterial roads owned by the City. This method does not apply to local roads , school zones or CDOT state highways. The roads to be evaluated were segmented by existing posted speed and street classification. The average length of evaluated segments is half a mile. Approximately 67 miles of roads were evaluated, divided into 137 segments. In these cases, the average measured speed was used for the methodology. As shown in Figure 8, a vast majority of the segments were in residential / mixed-use land use. Figure 9 shows street segments that were evaluated as part of the project.

Figure 8: Evaluated Roadway Segments by Land Use Type

This chart shows the miles of evaluated street segments by their surrounding land use. 3.6 miles of street segments are in business areas. 2.2 miles are in downtown areas. 15.1 miles are in industrial/agricultural areas. 46 miles are in residential/mixed use areas.

KEY DEFINITION

Operating Speed: actual vehicular speed collected in the field. It is often presented as a percentile. It is impacted by the posted speed limit, along with the design of the roadway, enforcement, etc.

  • 50th percentile speed: same as the median speed, it represents the speed at which 50% of the vehicles travel at or below.
  • 85th percentile speed: represents the speed that 85% of the vehicles travel at or below. Historically, this was the primary variable used to set speed limits.
  • Rounding criteria: established guidelines or rules utilized to adjust observed speeds to conform to the requirement that posted speeds must be multiples of five. When rounding observed speeds to match this criterion, there are typically two main approaches: rounding up to the nearest multiple of five or rounding down to the closest multiple of five. In the output of the methodology the following rounding criteria is used
    • C85: Closest 85th percentile
    • RD85: Rounded-down 85th percentile
    • C50: Closest 50th percentile
    • RD50: Rounded-down 50th percentile

Figure 9: Evaluated Street Segments

Figure 9 map of Evaluated Street Segments. Long description under header Text Alternatives.

City of Boulder’s approach to citywide speed limit setting introduces a five-layer evaluation process tailored to local parameters (Figure 10). It introduces a point-based system that aligns with Boulder Vision Zero values that utilizes local data.

Figure 10: Boulder Speed Limit Setting Methodology Flowchart

Figure 10, a Boulder Speed Limit Setting Methodology Flowchart. Long description under header Text Alternatives.

The first layer of evaluation is identifying if the segment is part of the existing High-Risk Network (HRN). The HRN, developed as part of the 2023-2027 Vision Zero Action Plan, represents just 7% of city streets but accounts for 48% of serious- and fatal-injury crashes in the city. Within the methodology, street segments in the HRN are set to default to lower speeds by recommending to the Rounded Down 50th-percentile speed. This priority step aligns with the city’s Vision Zero commitment, streamlines the process by eliminating Subsequent layers of analysis, and aligns with the Safer Speeds aspect of the Safe Systems Approach. The second layer of evaluation is a point system that quantifies the need for lower speeds. Points were awarded to locations based on 16 factors (Table 2): Each factor is given a point, ranging from 1-15, depending on its priority in determining the appropriate posted speed limit. For example, a segment with a crash resulting in a fatality is given 15 points, while presence of a park within ¼ mile of the segment is given 2 points. Thirty-five percent of the available points are allocated to crashrelated factors, thirty-five percent to multimodal use and facility factors, twenty-four percent to road configuration factors, and six percent by the presence of trip generators factors. This step reinforces the data-driven approach of the methodology and defines Boulder-specific thresholds for all 16 factors. The assigned points determine the associated tier for the segment, with Tier I being 55-100 points, Tier 2 being 34-54 points, and Tier 3 being 0-33 points.

Figure 11: Factors Defining the Need for Lower Speeds

A pie chart shows the percentage of points allocated to each factor. Thirty-five percent of the available points are allocated to crash related factors, thirty-five percent to multimodal use and facility factors, twenty-four percent to road configuration factors, and six percent by the presence of trip generators factors.

Table 2: Evaluated Factors and Points Assigned

FactorCategoryPriorityMaximum Points
Fatal crashes Crash Priority 1 15
Pedestrian/Bike crashes Crash Priority 110
Speed crashes Priority 110
Multimodal Crossings MultimodalPriority 15
Pedestrian facilities MultimodalPriority 15
Pedestrian activity MultimodalPriority 11
Bike facilities MultimodalPriority 15
Bike activityMultimodalPriority 110
Driveway Access Density Road ConfigurationPriority 15
On street parking Road ConfigurationPriority 25
Unsignalized Density Road ConfigurationPriority 25
Signalized intersection density Road ConfigurationPriority 25
Number of Through lanes Road ConfigurationPriority 24
SchoolsTrip generators Priority 3 2
Park Trip generators Priority 32
Assisted living facility Trip generators Priority 32

Figure 12: Three Tiers of Need for Lower Speed

Figure 12 map of Three Tiers of Need for Lower Speed. Long description under header Text Alternatives.

The third layer of the evaluation is an output table (Table 3), where the functional classification, the land use, and the point system evaluation play a role in determining the observed speed percentile that should govern the speed limit setting. The possible outputs of the methodology are closest 85th percentile (C85), roundeddown 85th percentile (RD85), closest 50th percentile (C50), and rounded down 50th percentile (RD50). (E.g. if the 50th percentile speed is 33 mph, then the C50 output would be 35 mph, while the RD50 output would be 30 mph, etc.).

Table 3: Output Table - Recommended Rounding Percentile of Speed

Speed CategoryLand Use
Residential/ Mixed UsedBusiness/ DowntownIndustrial/ Agricultural
Tier IIITier IITier ITier IIITier IITier ITier IIITier IITier I
CollectorC50RD50 RD50 C50 C50 RD50 RD85 RD85 C50
Minor Arterial C50 C50 RD50 RD85 C50 C50 C85 RD85 RD85
Principal Arterial RD85 C50 C50 C85 RD85 RD85 C85 C85 RD85

The fourth layer is the Speed Limit Table (Table 4) which establishes ranges of appropriate speeds for each land use and functional classification group. The table is also a policy defining piece of the methodology, where the city is able to define target speeds irrespective of the observed operational speeds of the corridor. Whenever the operating speeds in a segment falls outside the speed range shown in the Speed Limit Table, the values in the table will dictate the speed limit methodology’s recommendation for the segment

Table 4: Recommended Speed Limit Ranges by Functional Classification and Land Use

Functional ClassificationLand Use
DowntownResidential/Mixed Use
/Business/Public		Industrial/
Agricultural
Local (shown for informational purposes only)20 mph20 mph20 mph
Collector20 - 25 mph20 - 30 mph25 - 35 mph
Minor Arterial20 - 35 mph30 - 40 mph
Principal Arterial25 - 35 mph30 - 45 mph

The fifth and final layer is to apply engineering judgement to ensure that the final recommendation is context-sensitive, financially and technically feasible, and meets the expectation of the community. City staff will review the corridor, its surrounding areas, and the speed recommended by the methodology to validate and refine the results as needed. Special attention will be given to corridors near the city limits where roads transition from Boulder’s jurisdiction to County roads and consistency on the posted speed limit is expected. Segments with recommended changes greater than 5 miles per hour will be manually reviewed as well. Long corridors will also be checked to ensure consistency on the posted speed limits, ensuring that the posted signs do not unnecessarily change without significant changes on the road context. While city staff understand and respect the methodology used to develop recommended speed limits on evaluated segments, as part of its unwavering commitment to Vision Zero, the city is not planning to raise any posted speed limits at this time. Engineering judgment will be applied to segments with recommended speed limit reductions to ensure consistency, credibility, and enforceability. The proposed Boulder speed limit setting methodology not only incorporates city-specific parameters but also establishes a precedent to determine policies that extend beyond the operating speeds.

8. Preliminary Results

VIII. Preliminary Results

Preliminary results account for the full methodology application on all the evaluated segments. Fifteen of the 137 segments did not have speed data available and for those locations; the methodology suggests the rounding criteria for those segments (i.e., rounded down 50th percentile versus closest 85th percentile). With a focus on a data-driven approach, vehicular speed and volume data was collected at 206 new locations, in three-day (Tuesday through Thursday) periods that varied from October 31 to December 21, 2023, excluding major holidays and weekends, as shown on Figure 13. Additional data previously collected by the city from various other efforts were also included in the evaluation. A total of 240 speed data collection points were incorporated in this study. This represented one of the largest data collection efforts ever undertaken by the city. Figure 14 shows the recommended speed limits after the application of the methodology. Figure 15 shows the methodology-recommended change in speed limit after comparing it with the existing posted speed limit for each of the street segments. Neither Figure 14 nor Figure 15 account for the final layer of engineering judgment. The goal is to showcase how the methodology performs by itself before city staff refinement to demonstrate the robustness of the methodology.

Figure 13: Speed Data Collection Location

Figure 13 map of Speed Data Collection Location. Long description under header Text Alternatives.

Figure 14: Methodology-Recommended Speed Limits (Does Not Account for Engineering Judgement Refinements)

Figure 14 map of Methodology-Recommended Speed Limits. Long description under header Text Alternatives.

Figure 14 shows the methodology-recommended speed limit, before the engineering judgement refinement. It can be observed that the lower speed limits are found towards the city center and near the downtown area. The highest speed limits are found in industrial/ agricultural areas towards the city’s borders. The speed limit on those higher-speed locations will need to be evaluated and refined to ensure a consistent transition between city and County roads and CDOT state highways.

Table 5 shows the length of the segments (miles) by functional classification and methodology-recommended speed limit. The methodology indicated that the recommended speed limit should be 40 mph on 4 miles, and 45 mph on 3.2 miles of approximately 67 miles of evaluated roadway. There were 5.5 miles of segments that did not have available speed data. These are shown in the RD50, C50, and RD85 columns of Table 5. Once data is collected on those segments, the rounding criteria can easily be applied

Speed Category:Recommended Speed Limit (mph) or Rounding CriteriaTotal Length (mi.)
202530254045RD50 C50RD85
Total Length (mi.)
Collector3.1 9.6 10.82.5 2.1 1.7 0.5 30.4
Minor Arterial1.54.6 7.7 4.8 3.5 0.7 22.9
Principal Arterial 2.0 4.4 1.9 0.4 3.2 0.4 12.4
Total Length (mi.) 5.8 16.223.0 9.2 4.0 3.22.5 2.4 0.5 66.9

Figure 15: Methodology - Recommended Change in Speed Limit (Does not Account for Engineering Judgement Refinements)

Figure 15 map of Methodology - Recommended Change in Speed Limit. Long description under header Text Alternatives.

Figure 15 shows the methodology recommended changes to the speed limit and Table 6 documents the length of the segments by recommended change. Along the HRN, no increases to speed limits are recommended. Of the miles of roads evaluated for which speed data was available, approximately half (30 miles) are not suggested for changes in speed limit. The most common recommended change is a 5 mph reduction, which applies to 20.7 miles of the network evaluated. Less than 8 miles are suggested for increases in the speed limit; however, based on a city policy decision, speed limits are not planned to be raised on any segments at this time.

Table 6: Total Length of Methodology-Recommended Speed Limit Change by HRN and Non-HRN Streets

CategorySuggested Change in Speed Limit (mph)
-10-50510Total Length (mi.)
High Risk Network (HRN) 1.6 11.5 5.8 0.0 0.0 18.9
Not on HRN1.5 9.2 24.2 6.6 0.8 42.4
Total Length (mi.) 3.2 20.7 30.06.6 0.861.4

10. Implementation

The project team will continue to work on validate the results of the methodology and refine the results through engineering judgement. City staff continues to work on the implementation plan and signing recommendations. In accordance with the timeline of the 2023-2027 Vision Zero Action Plan, speed limit changes are expected to be fully implemented across the transportation system by 2027. Given the magnitude of anticipated changes across the system, it is likely a phased implementation will be needed to ensure the following:

  • Motorists are given proper notice of speed limit changes through press releases, website updates, and social media posts.
  • Other activities required due to speed limit changes are coordinated with implementation. These include such things as:
    • Adjustments to coordinated traffic signal timing plans and other signal timing parameters that are impacted by the posted speed limit.
    • Assessment of sign locations.
  • The timing and use of automated enforcement along corridors with recommended speed limit changes will also need to be coordinated with the Police Department.

An implementation report should be prepared for each of the street segments that addresses the following:

  • Review of the data used in the methodology and updates to it, if necessary.
  • Review the ends of the street segment and ensure the transition is appropriate.
  • Coordinate with Boulder County and CDOT if county or state-owned streets are adjacent to the project
  • Conduct a site visit and collect data on existing speed limit sign locations and conditions.
  • Prepare a new speed limit sign design plans that shows the location of the new signs, removal of old signs, and quantifies the items. New signs should be placed at:
    • Approximately 0.25 mile spacing
    • The far-side of all collector and arterial intersections.

Figure Text Alternatives

Streets in Boulder are classified as local, collector, minor arterial and principal arterial. This map highlights the collector, minor arterial, and principal arterial streets.

Collectors:

  1. 47th Street from Diagonal Highway to Jay Road
  2. Baseline Road from Flagstaff Road to 9th Street
  3. 9th Street from Balsam Avenueto Hawthorn Avenue
  4. 9th Street from Marine Street to Arapahoe Avenue
  5. Balsam Avenue from Broadway to 19th Street
  6. Edgewood Drive from 19th Street to Folsom Street
  7. 9th Street from Baseline Road to University Avenue
  8. Pine Street from 11th Street to 17th Street
  9. Baseline Road from 9th Street to Broadway
  10. Walnut Street from 15th Street to 17th Street
  11. Pine Street from 17th Street to 20th Street
  12. Pine Street from 20th Street to Folsom Street
  13. Pine Street from Folsom Street to 28th Street
  14. 17th Street from Walnut Street to Pine Street
  15. 17th Street from University Avenueto Arapahoe Avenue
  16. 17th Street from Arapahoe Avenueto Walnut Street
  17. 19th Street from Violet Avenueto Yarmouth Avenue
  18. Dartmouth Avenue from cul-de-sac to Broadway
  19. Table Mesa Drive from Vassar Drive to Lehigh Street
  20. Lehigh Street from Greenbriar Boulevard to Table Mesa Drive
  21. Moorhead Avenue from 27th Way to Table Mesa Drive
  22. 32nd Street from Walnut Street to Prairie Avenue
  23. Kalmia Avenue from 28th Street to Foothills Parkway ramp
  24. Kalmia Avenue from 26th Street to 28th Street
  25. Kalmia Avenue from 28th Street to east end of Kalmia
  26. 55th Street from Baseline Road to Arapahoe Avenue
  27. Spine Road from Longbow Drive to 63rd Street
  28. 63rd Street from Stazio Drive to Stazio Drive
  29. Linden Avenue from Linden Drive to Broadway
  30. Lee Hill Drive from City Limits to Broadway
  31. Arapahoe Avenue from 6th Street to 9th Street
  32. 19th Street from Iris Avenueto Violet Avenue
  33. 33rd Street from Arapahoe to Walnut Street
  34. Walnut Street from 30th Street to cul-de-sac
  35. 47th Street from Pearl Parkway to Valmont Road
  36. 47th Street from Valmont Road to Diagonal Highway
  37. Spine Road from City Limits to Longbow Drive
  38. Gunbarrel Avenue from Spine Road to 63rd Street
  39. 63rd Street from Arapahoe Avenueto Stazio Drive
  40. Spine Road from 63rd Street to Lookout Road
  41. Hawthorn Avenue from 9th Street to Broadway
  42. Sioux Drive from 55th Street to Baseline Road
  43. 55th Street from South Boulder Road to Sioux Drive
  44. Greenbriar Boulevard from Lehigh Street to Broadway
  45. Gillaspie Drive from Greenbriar Boulevard to Table Mesa Drive
  46. Walnut Street from Folsom Street to 26th Street
  47. 26th Street from McGuckin Way to Pearl Street
  48. 26th Street from Folsom Street to Jay Road
  49. Walnut Street from 17th Street to Folsom Street
  50. University Avenue from Broadway to 17th Street
  51. University Avenue from Marshall Street to Broadway
  52. Pearl Street from 47th Street to 50th Street

Minor Arterials:

  1. Colorado Avenue from 30th Street to Foothills Parkway
  2. Valmont Road from 47th Street to Airport Boulevard
  3. Valmont Road from Airport Boulevard to 55th Street
  4. 55th Street from Flatiron Parkway to Arapahoe Avenue
  5. Baseline Road from Sioux Drive to Cherryvale Road
  6. 71st Street from Winchester Circle to Mineral Road
  7. 9th Street from Dewey Avenueto Balsam Avenue
  8. Mapleton Avenue from 4th Street to 9th Street
  9. 9th Street from Walnut Street to Pearl Street
  10. 9th Street from Pearl Street to Mapleton Avenue
  11. Mapleton Avenue from 9th Street to Broadway
  12. 9th Street from Arapahoe Avenueto Walnut Street
  13. 20th Street from Walnut Street to Pine Street
  14. 20th Street from Pine Street to 2879 aley
  15. Monarch Road from 63rd Street to 71st Street
  16. 9th Street from Mapleton Avenueto Dewey Avenue
  17. Pearl Street from 7th Street to 11th Street
  18. Walnut Street from 7th Street to 11th Street
  19. Spruce Street from 11th Street to 15th Street
  20. 11th Street from Walnut Street to Spruce Street
  21. Walnut Street from 11th Street to 15th Street
  22. Pearl Street from 15th Street to 17th Street
  23. Violet Avenue from Broadway to 19th Street
  24. Violet Avenue from 19th Street to 28th Street
  25. Valmont Road from Folsom Street to 30th Street
  26. 30th Street from Colorado Avenueto Arapahoe Avenue
  27. Colorado Avenue from Folsom Street to 30th Street
  28. 27th Way from Broadway to Baseline Road
  29. Table Mesa Drive from Lehigh Street to Broadway
  30. 30th Street from Valmont Road to Diagonal Highway
  31. 30th Street from Pearl Street to Valmont Road
  32. 30th Street from Arapahoe Avenueto Pearl Parkway
  33. Valmont Road from 30th Street to 47th Street
  34. 30th Street from Baseline Road to Colorado Avenue
  35. Airport Boulevard from Valmont Road to cul-de-sac
  36. Baseline Road from Foothills Parkway to Sioux Drive
  37. 55th Street from Flatiron Parkway to Valmont Road
  38. 71st Street from Kalmia Avenue to Winchester Circle
  39. Lookout Road from Kalmia Avenue to 75th Street
  40. Arapahoe Avenue from 9th Street to 17th Street
  41. Arapahoe Avenue from 17th Street to Folsom Street
  42. Lee Hill Drive from Broadway to 28th Street
  43. Yarmouth Avenue from Broadway to 28th Street
  44. Pearl Street from 17th Street to 20th Street
  45. Pearl Street from 20th Street to Folsom Street
  46. 20th Street from 2879 aley to 19th Street
  47. 19th Street from 20th Street to Iris Avenue
  48. Folsom Street from Colorado Avenue to Arapahoe Avenue
  49. Folsom Street from Pine Street to Valmont Road
  50. Folsom Street from Valmont Road to 26th Street
  51. Folsom Street from Pearl Street to Pine Street
  52. Folsom Street from Arapahoe Avenueto Pearl Street
  53. Lookout Road from 63rd Street to Gunpark Drive
  54. 15th Street from Walnut Street to Spruce Street
  55. Jay Road from 26th Street to 28th Street

Principal Arterials:

  1. Broadway from Iris Avenue to Redwood Avenue
  2. Iris Avenue from 19th Street to 26th Street
  3. Iris Avenue from 26th Street to 28th Street
  4. Arapahoe Avenue from Folsom Street to 28th Street
  5. Baseline Road from US36 ramp to 30th Street
  6. Pearl Parkway from 30th Street to 47th Street
  7. Pearl Parkway from 47th Street to 49th
  8. Table Mesa Drive from Broadway to Moorhead Avenue
  9. Table Mesa Drive from Moorhead Avenue to South Boulder Road
  10. Baseline Road from Mohawk Drive to Foothills Parkway
  11. 63rd Street from Lookout Road to Boulder Reservoir Water Treatment Plant Road
  12. 63rd Street from Boulder Reservoir Water Treatment Plant Road to Reservoir Trail
  13. Broadway from Lee Hill Drive to Foothills Highway
  14. Broadway from Redwood Avenue to Violet Avenue
  15. Baseline Road from 30th Street to Mohawk Drive
  16. Pearl Parkway from 49th to Valmont Road
  17. 63rd Street from private Road to Monarch Road
  18. 63rd Street from Spine Road to Lookout Road
  19. 63rd Street from Gunbarrel Avenue to Spine Road
  20. 63rd Street from city limits to Gunbarrel Avenue
  21. Broadway from Violet Avenue to Lee Hill Drive
  22. Broadway from Canyon Boulevard to Mapleton Avenue
  23. Broadway from Mapleton Avenue to Balsam Avenue
  24. Broadway from Balsam Avenue to Iris Avenue
  25. Pearl Street from Folsom Street to 28th Street
  26. Pearl Street from 28th Street to 30th Street
  27. Balsam Avenue from 9th Street to Broadway
  28. Iris Avenue from Broadway to 19th Street

A chart shows the distribution of speed limits by street classification. All local streets have a speed limit of 20 mph, unless otherwise posted. For collectors, 58% are 25 mph, 32% are 30 mph, 7% are 35 mph, and 3% are 40 mph. For minor arterials, 8% are 20 mph, 8% are 25 mph, 25% are 30 mph, 39% are 35 mph, 16% are 40 mph, and 4% are 45 mph. For principal arterials, 2% are 25 mph, 19% are 30 mph, 41% are 35 mph, 32% are 40 mph, and 6% are 45 mph.

This map shows categories of existing zoning classifications – downtown, residential/mixed-use/public, business, and industrial/agricultural. The speed limit setting methodology takes into consideration these existing land-uses on either side of the Street. Residential/mixed use/public land-use covers approximately 78% of Boulder’s land area, concentrated in south, west, and north Boulder. The business land use covers 5% of Boulder’s land area and is concentrated in central Boulder and Gunbarrel. Industrial/agricultural makes up 16% of city land area and occurring in east and north Boulder and Gunbarrel. Finally, the downtown zoning classification occurs least often, making up 1% of Boulder’s land area in the downtown area.

A chart shows the percent of land area covered by each zoning classification and the percent of street segments in those categories analyzed in the project. Business zoning makes up 5% of city land area. 5% of the street segments analyzed in this project are in business areas. Downtown zoning makes up 1% of city land area. 3% of street segments analyzed are in downtown areas. Industrial/agricultural zoning makes up 16% of city land area. 23% of street segments analyzed are in industrial/agricultural areas. Residential/mixed-use zoning makes up 78% of city land area. 69% of street segments analyzed are in residential/mixed-use areas.

This map shows the street segments evaluated in this study, categorized by their surrounding land use. There are 12 street segments in the business land use, 10 in downtown, 28 in industrial/agricultural, and 87 in residential/mixed use/public.

Business:

  1. Arapahoe Avenue from Folsom Street to 28th Street
  2. Baseline Road from Ramp to 30th Street
  3. Baseline Road from Mohawk Drive to Foothills Parkway
  4. Broadway from Mapleton Avenue to Balsam Avenue
  5. Pearl Street from Folsom Street to 28th Street
  6. Pearl Street from 28th Street to 30th Street
  7. 32nd Street from Walnut Street to Prairie Avenue
  8. 30th Street from Pearl Street to Valmont Road
  9. 30th Street from Arapahoe Avenue to Pearl Parkway
  10. Folsom Street from Arapahoe Avenue to Pearl Street
  11. Walnut Street from Folsom Street to 26th Street
  12. 26th Street from McGuckin Way to Pearl Street

Downtown:

  1. 9th Street from Walnut Street to Pearl Street
  2. Broadway from Canyon Boulevard to Mapleton Avenue
  3. Walnut Street from 15th Street to 17th Street
  4. Pearl Street from 7th Street to 11th Street
  5. Walnut Street from 7th Street to 11th Street
  6. Spruce Street from 11th Street to 15th Street
  7. 11th Street from Walnut Street to Spruce Street
  8. Walnut Street from 11th Street to 15th Street
  9. Pearl Street from 15th Street to 17th Street
  10. 15th Street from Walnut Street to Spruce Street

Industrial/Agricultural:

  1. Valmont Road from 47th Street to Airport Boulevard
  2. Valmont Road from Airport Boulevard to 55th Street
  3. 55th Street from Flatiron Parkway to Arapahoe Avenue
  4. 71st Street from Winchester Circle to Mineral Road
  5. Pearl Parkway from 30th Street to 47th Street
  6. Pearl Parkway from 47th Street to 49th Street
  7. 63rd Street from Lookout Road to Boulder Reservoir Water Treatment Plant Road
  8. 63rd Street from Boulder Reservoir Water Treatment Plant Road to Reservoir Trail
  9. Broadway from Lee Hill Drive to Foothills Highway
  10. Pearl Parkway from 49th Street to Valmont Road
  11. 63rd Street from private road to Monarch Road
  12. 63rd Street from Spine Road to Lookout Road
  13. 63rd Street from Gunbarrel Avenue to Spine Road
  14. 63rd Street from city limits to Gunbarrel Avenue
  15. Monarch Road from 63rd Street to 71st Street
  16. Airport Boulevard from Valmont Road to cul-de-sac
  17. 55th Street from Flatiron Parkway to Valmont Road
  18. 71st Street from Kalmia Avenue to Winchester Circle
  19. Spine Road from Longbow Drive to 63rd Street
  20. 63rd Street from Stazio Drive to Stazio Drive
  21. Lookout Road from 63rd Street to Gunpark Drive
  22. 33rd Street from Arapahoe to Walnut Street
  23. Walnut Street from 30th Street to cul-de-sac
  24. 47th Street from Pearl Parkway to Valmont Road
  25. Gunbarrel Avenue from Spine Road to 63rd Street
  26. 63rd Street from Arapahoe Avenue to Stazio Drive
  27. Spine Road from 63rd Street to Lookout Road
  28. Pearl Street from 47th Street to 50th Street

Residential/Mixed Use/Public:

  1. Colorado Avenue from 30th Street to Foothills Parkway
  2. Baseline Road from Sioux Drive to Cherryvale Road
  3. Broadway from Iris Avenue to Redwood Avenue
  4. Iris Avenue from 19th Street to 26th Street
  5. Iris Avenue from 26th Street to 28th Street
  6. Table Mesa Drive from Broadway to Moorhead Avenue
  7. Table Mesa Drive from Moorhead Avenue to South Boulder Road
  8. 9th Street from Dewey Avenue to Balsam Avenue
  9. Mapleton Avenue from 4th Street to 9th Street
  10. 9th Street from Pearl Street to Mapleton Avenue
  11. Mapleton Avenue from 9th Street to Broadway
  12. 9th Street from Arapahoe Avenue to Walnut Street
  13. 20th Street from Walnut Street to Pine Street
  14. 20th Street from Pine Street to 2879 aley
  15. Broadway from Redwood Avenue to Violet Avenue
  16. Baseline Road from 30th Street to Mohawk Drive
  17. 47th Street from Diagonal Highway to Jay Road
  18. Broadway from Violet Avenue to Lee Hill Drive
  19. Broadway from Balsam Avenue to Iris Avenue
  20. Baseline Road from Flagstaff Road to 9th Street
  21. 9th Street from Balsam Avenue to Hawthorn Avenue
  22. 9th Street from Marine Street to Arapahoe Avenue
  23. Balsam Avenue from Broadway to 19th Street
  24. Edgewood Drive from 19th Street to Folsom Street
  25. 9th Street from Baseline Road to University Avenue
  26. Pine Street from 11th Street to 17th Street
  27. Baseline Road from 9th Street to Broadway
  28. Pine Street from 17th Street to 20th Street
  29. Pine Street from 20th Street to Folsom Street
  30. Pine Street from Folsom Street to 28th Street
  31. 17th Street from Walnut Street to Pine Street
  32. 17th Street from University Avenue to Arapahoe Avenue
  33. 17th Street from Arapahoe Avenue to Walnut Street
  34. 19th Street from Violet Avenue to Yarmouth Avenue
  35. Dartmouth Avenue from cul-de-sac to Broadway
  36. Table Mesa Drive from Vassar Drive to Lehigh Street
  37. Lehigh Street from Greenbriar Boulevard to Table Mesa Drive
  38. Moorhead Avenue from 27th Way to Table Mesa Drive
  39. 9th Street from Mapleton Avenue to Dewey Avenue
  40. Violet Avenue from Broadway to 19th Street
  41. Violet Avenue from 19th Street to 28th Street
  42. Valmont Road from Folsom Street to 30th Street
  43. 30th Street from Colorado Avenue to Arapahoe Avenue
  44. Colorado Avenue from Folsom Street to 30th Street
  45. 27th Way from Broadway to Baseline Road
  46. Table Mesa Drive from Lehigh Street to Broadway
  47. 30th Street from Valmont Road to Diagonal Highway
  48. Valmont Road from 30th Street to 47th Street
  49. 30th Street from Baseline Road to Colorado Avenue
  50. Baseline Road from Foothills Parkway to Sioux Drive
  51. Kalmia Avenue from 28th Street to Foothills Parkway Ramp
  52. Kalmia Avenue from 26th Street to 28th Street
  53. Kalmia Avenue from 28th Street to east end of Kalmia
  54. Lookout Road from Kalmia Avenue to 75th Street
  55. 55th Street from Baseline Road to Arapahoe Avenue
  56. Balsam Avenue from 9th Street to Broadway
  57. Arapahoe Avenue from 9th Street to 17th Street
  58. Arapahoe Avenue from 17th Street to Folsom Street
  59. Lee Hill Drive from Broadway to 28th Street
  60. Yarmouth Avenue from Broadway to 28th Street
  61. Pearl Street from17th Street to 20th Street
  62. Pearl Street from 20th Street to Folsom Street
  63. 20th Street from 2879 aley to 19th Street
  64. 19th Street from 20th Street to Iris Avenue
  65. Folsom Street from Colorado Avenue to Arapahoe Avenue
  66. Folsom Street from Pine Street to Valmont Road
  67. Folsom Street from Valmont Road to 26th Street
  68. Folsom Street from Pearl Street to Pine Street
  69. Linden Avenue from Linden Drive to Broadway
  70. Lee Hill Drive from city limits to Broadway
  71. Arapahoe Avenue from 6th Street to 9th Street
  72. 19th Street from Iris Avenue to Violet Avenue
  73. 47th Street from Valmont Road to Diagonal Highway
  74. Spine Road from city limits to Longbow Drive
  75. Hawthorn Avenue from 9th Street to Broadway
  76. Iris Avenue from Broadway to 19th Street
  77. Aurora Avenue from 30th Street to Mohawk Road
  78. Sioux Drive from 55th Street to Baseline Road
  79. 55th Street from South Boulder Road to Sioux Drive
  80. Greenbriar Boulevard from Lehigh Street to Broadway
  81. Gillaspie Drive from Greenbriar Boulevard to Table Mesa Drive
  82. Glenwood Drive from Folsom Street to 30th Street
  83. 26th Street from Folsom Street to Jay Road
  84. Walnut Street from 17th Street to Folsom Street
  85. Jay Road from 26th Street to 28th Street
  86. University Avenue from Broadway to 17th Street
  87. University Avenue from Marshall Street to Broadway

This flow chart shows the methodology in 5 layers. The first layer of evaluation is identifying if the segment is part of the existing High-Risk Network (HRN). The HRN, developed as part of the 2023-2027 Vision Zero Action Plan, represents just 7% of city streets but accounts for 48% of serious- and fatal-injury crashes in the city. Within the methodology, street segments in the HRN are set to default to lower speeds by recommending to the rounded-down 50th-percentile speed. This priority step aligns with the city’s Vision Zero commitment, streamlines the process by eliminating Subsequent layers of analysis, and aligns with the Safer Speeds aspect of the Safe Systems Approach.

The second layer of evaluation is a point system that quantifies the need for lower speeds. Points were awarded to locations based on 16 factors. Each factor is given a point, ranging from 1-15, depending on its priority in determining the appropriate posted speed limit. For example, a segment with a crash resulting in a fatality is given 15 points, while presence of a park within ¼ mile of the segment is given 2 points. Thirty-five percent of the available points are allocated to crash related factors, thirty-five percent to multimodal use and facility factors, twenty-four percent to road configuration factors, and six percent by the presence of trip generators factors. This step reinforces the data-driven approach of the methodology and defines Boulder specific thresholds for all 16 factors. The assigned points determine the associated tier for the segment, with Tier I being 55-100 points, Tier 2 being 34-54 points, and Tier 3 being 0-33 points.

The third layer of the evaluation is an output table, where the functional classification, the land use, and the point system evaluation play a role in determining the observed speed percentile that should govern the speed limit setting. The possible outputs of the methodology are closest 85th percentile (C85), rounded-down 85th percentile (RD85), closest 50th percentile (C50), and rounded down 50th percentile (RD50). (E.g. if the 50th percentile speed is 33 mph, then the C50 output would be 35 mph, while the RD50 output would be 30 mph, etc.).

The fourth layer is the Speed Limit Table which establishes ranges of appropriate speeds for each land use and functional classification group. The table is also a policy defining piece of the methodology, where the city is able to define target speeds irrespective of the observed operational speeds of the corridor. Whenever the operating speeds in a segment falls outside the speed range shown in the Speed Limit Table, the values in the table will dictate the speed limit methodology’s recommendation for the segment.

The fifth and final layer is to apply engineering judgement to ensure that the final recommendation is context-sensitive, financially and technically feasible, and meets the expectation of the community. City staff will review the corridor, its surrounding areas, and the speed recommended by the methodology to validate and refine the results as needed. Special attention will be given to corridors near the city limits where roads transition from Boulder’s jurisdiction to County roads and consistency on the posted speed limit is expected. Segments with recommended changes greater than 5 miles per hour will be manually reviewed as well. Long corridors will also be checked to ensure consistency on the posted speed limits, ensuring that the posted signs do not unnecessarily change without significant changes on the road context. While city staff understand and respect the methodology used to develop recommended speed limits on evaluated segments, as part of its unwavering commitment to Vision Zero, the city is not planning to raise any posted speed limits at this time. Engineering judgment will be applied to segments with recommended speed limit reductions to ensure consistency, credibility, and enforceability. The proposed Boulder speed limit setting methodology not only incorporates city-specific parameters but also establishes a precedent to determine policies that extend beyond the operating speeds.

This map shows the evaluated street segments categorized into three tiers of need for lower speeds. The tiers were calculated using a 16-factor point system. Tier 1 consists of 39 street segments, Tier 2 of 58 segments, and Tier 3 of 40 segments.

Tier 1:

  1. Baseline Road from Ramp to 30th Street
  2. Table Mesa Drive from Broadway to Moorhead Avenue
  3. Table Mesa Drive from Moorhead Avenue to South Boulder Road
  4. Baseline Road from Mohawk Drive to Foothills Parkway
  5. 9th Street from Walnut Street to Pearl Street
  6. 9th Street from Pearl Street to Mapleton Avenue
  7. 9th Street from Arapahoe Avenue to Walnut Street
  8. 20th Street from Walnut Street to Pine Street
  9. Broadway from Lee Hill Drive to Foothills Highway
  10. Baseline Road from 30th Street to Mohawk Drive
  11. Broadway from Violet Avenue to Lee Hill Drive
  12. Broadway from Canyon Boulevard to Mapleton Avenue
  13. Pearl Street from Folsom Street to 28th Street
  14. Pine Street from 11th Street to 17th Street
  15. Baseline Road from 9th Street to Broadway
  16. 17th Street from Walnut Street to Pine Street
  17. 17th Street from University Avenue to Arapahoe Avenue
  18. 17th Street from Arapahoe Avenue to Walnut Street
  19. Moorhead Avenue from 27th Way to Table Mesa Drive
  20. Pearl Street from 7th Street to 11th Street
  21. Walnut Street from 7th Street to 11th Street
  22. Spruce Street from 11th Street to 15th Street
  23. 11th Street from Walnut Street to Spruce Street
  24. Walnut Street from 11th Street to 15th Street
  25. 30th Street from Colorado Avenue to Arapahoe Avenue
  26. Colorado Avenue from Folsom Street to 30th Street
  27. 30th Street from Pearl Street to Valmont Road
  28. 30th Street from Arapahoe Avenue to Pearl Parkway
  29. 30th Street from Baseline Road to Colorado Avenue
  30. Arapahoe Avenue from 9th Street to 17th Street
  31. Arapahoe Avenue from 17th Street to Folsom Street
  32. Lee Hill Drive from Broadway to 28th Street
  33. Folsom Street from Valmont Road to 26th Street
  34. Folsom Street from Arapahoe Avenue to Pearl Street
  35. 15th Street from Walnut Street to Spruce Street
  36. Aurora Avenue from 30th Street to Mohawk Road
  37. 26th Street from McGuckin Way to Pearl Street
  38. University Avenue from Broadway to 17th Street
  39. University Avenue from Marshall Street to Broadway

Tier 2:

  1. Colorado Avenue from 30th Street to Foothills Parkway
  2. Broadway from Iris Avenue to Redwood Avenue
  3. Iris Avenue from 26th Street to 28th Street
  4. Arapahoe Avenue from Folsom Street to 28th Street
  5. Pearl Parkway from 30th Street to 47th Street
  6. 9th Street from Dewey Avenue to Balsam Avenue
  7. Mapleton Avenue from 4th Street to 9th Street
  8. Mapleton Avenue from 9th Street to Broadway
  9. 20th Street from Pine Street to 2879 aley
  10. Broadway from Redwood Avenue to Violet Avenue
  11. 63rd Street from private road to Monarch Road
  12. Broadway from Mapleton Avenue to Balsam Avenue
  13. Broadway from Balsam Avenue to Iris Avenue
  14. Pearl Street from 28th Street to 30th Street
  15. Baseline Road from Flagstaff Road to 9th Street
  16. 9th Street from Balsam Avenue to Hawthorn Avenue
  17. 9th Street from Marine Street to Arapahoe Avenue
  18. Balsam Avenue from Broadway to 19th Street
  19. Edgewood Drive from 19th Street to Folsom Street
  20. 9th Street from Baseline Road to University Avenue
  21. Walnut Street from 15th Street to 17th Street
  22. Pine Street from 17th Street to 20th Street
  23. Pine Street from 20th Street to Folsom Street
  24. Pine Street from Folsom Street to 28th Street
  25. 19th Street from Violet Avenue to Yarmouth Avenue
  26. Dartmouth Avenue from cul-de-sac to Broadway
  27. Table Mesa Drive from Vassar Drive to Lehigh Street
  28. Lehigh Street from Greenbriar Boulevard to Table Mesa Drive
  29. 9th Street from Mapleton Avenue to Dewey Avenue
  30. Pearl Street from 15th Street to 17th Street
  31. Violet Avenue from Broadway to 19th Street
  32. Valmont Road from Folsom Street to 30th Street
  33. Table Mesa Drive from Lehigh Street to Broadway
  34. 30th Street from Valmont Road to Diagonal Highway
  35. Valmont Road from 30th Street to 47th Street
  36. Kalmia Avenue from 26th Street to 28th Street
  37. 55th Street from Baseline Road to Arapahoe Avenue
  38. Balsam Avenue from 9th Street to Broadway
  39. Yarmouth Avenue from Broadway to 28th Street
  40. Pearl Street from 17th Street to 20th Street
  41. Pearl Street from 20th Street to Folsom Street
  42. 20th Street from 2879 aley to 19th Street
  43. 19th Street from 20th Street to Iris Avenue
  44. Folsom Street from Colorado Avenue to Arapahoe Avenue
  45. Folsom Street from Pine Street to Valmont Road
  46. Folsom Street from Pearl Street to Pine Street
  47. Lookout Road from 63rd Street to Gunpark Drive
  48. Lee Hill Drive from city limits to Broadway
  49. Arapahoe Avenue from 6th Street to 9th Street
  50. Walnut Street from 30th Street to cul-de-sac
  51. Spine Road from 63rd Street to Lookout Road
  52. Hawthorn Avenue from 9th Street to Broadway
  53. Iris Avenue from Broadway to 19th Street
  54. Gillaspie Drive from Greenbriar Boulevard to Table Mesa Drive
  55. Walnut Street from Folsom Street to 26th Street
  56. Glenwood Drive from Folsom Street to 30th Street
  57. 26th Street from Folsom Street to Jay Road
  58. Walnut Street from 17th Street to Folsom Street

Tier 3:

  1. Valmont Road from 47th Street to Airport Boulevard
  2. Valmont Road from Airport Boulevard to 55th Street
  3. 55th Street from Flatiron Parkway to Arapahoe Avenue
  4. Baseline Road from Sioux Drive to Cherryvale Road
  5. 71st Street from Winchester Circle to Mineral Road
  6. Iris Avenue from 19th Street to 26th Street
  7. Pearl Parkway from 47th Street to 49th Street
  8. 63rd Street from Lookout Road to Boulder Reservoir Water Treatment Plant Road
  9. 63rd Street from Boulder Reservoir Water Treatment Plant Road to Reservoir Trail
  10. Pearl Parkway from 49th Street to Valmont Road
  11. 63rd Street from Spine Road to Lookout Road
  12. 63rd Street from Gunbarrel Avenue to Spine Road
  13. 63rd Street from city limits to Gunbarrel Avenue
  14. 47th Street from Diagonal Highway to Jay Road
  15. Monarch Road from 63rd Street to 71st Street
  16. 32nd Street from Walnut Street to Prairie Avenue
  17. Violet Avenue from 19th Street to 28th Street
  18. 27th Way from Broadway to Baseline Road
  19. Airport Boulevard from Valmont Road to cul-de-sac
  20. Baseline Road from Foothills Parkway to Sioux Drive
  21. 55th Street from Flatiron Parkway to Valmont Road
  22. Kalmia Avenue from 28th Street to Foothills Parkway Ramp
  23. Kalmia Avenue from 28th Street to east end of Kalmia
  24. 71st Street from Kalmia Avenue to Winchester Circle
  25. Lookout Road from Kalmia Avenue to 75th Street
  26. Spine Road from Longbow Drive to 63rd Street
  27. 63rd Street from Stazio Drive to Stazio Drive
  28. Linden Avenue from Linden Drive to Broadway
  29. 19th Street from Iris Avenue to Violet Avenue
  30. 33rd Street from Arapahoe to Walnut Street
  31. 47th Street from Pearl Parkway to Valmont Road
  32. 47th Street from Valmont Road to Diagonal Highway
  33. Spine Road from city limits to Longbow Drive
  34. Gunbarrel Avenue from Spine Road to 63rd Street
  35. 63rd Street from Arapahoe Avenue to Stazio Drive
  36. Sioux Drive from 55th Street to Baseline Road
  37. 55th Street from South Boulder Road to Sioux Drive
  38. Greenbriar Boulevard from Lehigh Street to Broadway
  39. Jay Road from 26th Street to 28th Street
  40. Pearl Street from 47th Street to 50th Street

This map shows the recommended speed limits for the evaluated Street segments. There are 17 street segments recommended at 20 mph, 36 street segments recommended at 25 mph, 40 street segments recommended at 30 mph, 15 street segments recommended at 35 mph, 7 street segments recommended at 40 mph, and 7 street segments recommended at 45 mph.

20 mph:

  1. 9th Street from Walnut Street to Pearl Street
  2. 20th Street from Walnut Street to Pine Street
  3. 9th Street from Balsam Avenue to Hawthorn Avenue
  4. Pine Street from 11th Street to 17th Street
  5. 17th Street from Walnut Street to Pine Street
  6. 19th Street from Violet Avenue to Yarmouth Avenue
  7. Dartmouth Avenue from cul-de-sac to Broadway
  8. Pearl Street from 7th Street to 11th Street
  9. Walnut Street from 7th Street to 11th Street
  10. Walnut Street from 11th Street to 15th Street
  11. Pearl Street from 15th Street to 17th Street
  12. Pearl Street from17th Street to 20th Street
  13. Arapahoe Avenue from 6th Street to 9th Street
  14. Hawthorn Avenue from 9th Street to Broadway
  15. Aurora Avenue from 30th Street to Mohawk Road
  16. Glenwood Drive from Folsom Street to 30th Street
  17. Walnut Street from 17th Street to Folsom Street

25 mph:

  1. Baseline Road from Ramp to 30th Street
  2. 9th Street from Dewey Avenue to Balsam Avenue
  3. Mapleton Avenue from 4th Street to 9th Street
  4. 9th Street from Pearl Street to Mapleton Avenue
  5. Mapleton Avenue from 9th Street to Broadway
  6. 9th Street from Arapahoe Avenue to Walnut Street
  7. 20th Street from Pine Street to 2879 aley
  8. Broadway from Violet Avenue to Lee Hill Drive
  9. Broadway from Canyon Boulevard to Mapleton Avenue
  10. Broadway from Balsam Avenue to Iris Avenue
  11. Pearl Street from 28th Street to 30th Street
  12. Baseline Road from Flagstaff Road to 9th Street
  13. 9th Street from Marine Street to Arapahoe Avenue
  14. Balsam Avenue from Broadway to 19th Street
  15. Edgewood Drive from 19th Street to Folsom Street
  16. 9th Street from Baseline Road to University Avenue
  17. Baseline Road from 9th Street to Broadway
  18. Walnut Street from 15th Street to 17th Street
  19. Pine Street from 17th Street to 20th Street
  20. Pine Street from 20th Street to Folsom Street
  21. Pine Street from Folsom Street to 28th Street
  22. 17th Street from University Avenue to Arapahoe Avenue
  23. 17th Street from Arapahoe Avenue to Walnut Street
  24. Table Mesa Drive from Vassar Drive to Lehigh Street
  25. Lehigh Street from Greenbriar Boulevard to Table Mesa Drive
  26. Moorhead Avenue from 27th Way to Table Mesa Drive
  27. 9th Street from Mapleton Avenue to Dewey Avenue
  28. Colorado Avenue from Folsom Street to 30th Street
  29. Arapahoe Avenue from 9th Street to 17th Street
  30. Arapahoe Avenue from 17th Street to Folsom Street
  31. 20th Street from 2879 aley to 19th Street
  32. Folsom Street from Valmont Road to 26th Street
  33. Folsom Street from Pearl Street to Pine Street
  34. Folsom Street from Arapahoe Avenue to Pearl Street
  35. 26th Street from Folsom Street to Jay Road
  36. University Avenue from Marshall Street to Broadway

30 mph:

  1. Valmont Road from 47th Street to Airport Boulevard
  2. Broadway from Iris Avenue to Redwood Avenue
  3. Iris Avenue from 26th Street to 28th Street
  4. Pearl Parkway from 30th Street to 47th Street
  5. Table Mesa Drive from Broadway to Moorhead Avenue
  6. Table Mesa Drive from Moorhead Avenue to South Boulder Road
  7. Broadway from Lee Hill Drive to Foothills Highway
  8. Broadway from Redwood Avenue to Violet Avenue
  9. 47th Street from Diagonal Highway to Jay Road
  10. Broadway from Mapleton Avenue to Balsam Avenue
  11. Pearl Street from Folsom Street to 28th Street
  12. Violet Avenue from 19th Street to 28th Street
  13. Valmont Road from Folsom Street to 30th Street
  14. 27th Way from Broadway to Baseline Road
  15. Table Mesa Drive from Lehigh Street to Broadway
  16. 30th Street from Valmont Road to Diagonal Highway
  17. 30th Street from Pearl Street to Valmont Road
  18. 30th Street from Arapahoe Avenue to Pearl Parkway
  19. Valmont Road from 30th Street to 47th Street
  20. 30th Street from Baseline Road to Colorado Avenue
  21. Kalmia Avenue from 28th Street to Foothills Parkway Ramp
  22. Kalmia Avenue from 28th Street to east end of Kalmia
  23. 55th Street from Baseline Road to Arapahoe Avenue
  24. Balsam Avenue from 9th Street to Broadway
  25. Lee Hill Drive from Broadway to 28th Street
  26. Yarmouth Avenue from Broadway to 28th Street
  27. Pearl Street from 20th Street to Folsom Street
  28. 19th Street from 20th Street to Iris Avenue
  29. Folsom Street from Colorado Avenue to Arapahoe Avenue
  30. Folsom Street from Pine Street to Valmont Road
  31. Linden Avenue from Linden Drive to Broadway
  32. Lee Hill Drive from city limits to Broadway
  33. 19th Street from Iris Avenue to Violet Avenue
  34. 33rd Street from Arapahoe to Walnut Street
  35. Walnut Street from 30th Street to cul-de-sac
  36. 47th Street from Pearl Parkway to Valmont Road
  37. 47th Street from Valmont Road to Diagonal Highway
  38. Spine Road from city limits to Longbow Drive
  39. Gunbarrel Avenue from Spine Road to 63rd Street
  40. Greenbriar Boulevard from Lehigh Street to Broadway

35 mph:

  1. Colorado Avenue from 30th Street to Foothills Parkway
  2. Valmont Road from Airport Boulevard to 55th Street
  3. Baseline Road from Sioux Drive to Cherryvale Road
  4. Iris Avenue from 19th Street to 26th Street
  5. Baseline Road from 30th Street to Mohawk Drive
  6. Violet Avenue from Broadway to 19th Street
  7. 30th Street from Colorado Avenue to Arapahoe Avenue
  8. Airport Boulevard from Valmont Road to cul-de-sac
  9. Baseline Road from Foothills Parkway to Sioux Drive
  10. Lookout Road from Kalmia Avenue to 75th Street
  11. Spine Road from Longbow Drive to 63rd Street
  12. 63rd Street from Stazio Drive to Stazio Drive
  13. 63rd Street from Arapahoe Avenue to Stazio Drive
  14. Spine Road from 63rd Street to Lookout Road
  15. Iris Avenue from Broadway to 19th Street

40 mph:

  1. 55th Street from Flatiron Parkway to Arapahoe Avenue
  2. 71st Street from Winchester Circle to Mineral Road
  3. 63rd Street from Lookout Road to Boulder Reservoir Water Treatment Plant Road
  4. Monarch Road from 63rd Street to 71st Street
  5. 55th Street from Flatiron Parkway to Valmont Road
  6. 71st Street from Kalmia Avenue to Winchester Circle
  7. Lookout Road from 63rd Street to Gunpark Drive

45 mph:

  1. Pearl Parkway from 47th Street to 49th Street
  2. 63rd Street from Boulder Reservoir Water Treatment Plant Road to Reservoir Trail
  3. Pearl Parkway from 49th Street to Valmont Road
  4. 63rd Street from private road to Monarch Road
  5. 63rd Street from Spine Road to Lookout Road
  6. 63rd Street from Gunbarrel Avenue to Spine Road
  7. 63rd Street from city limits to Gunbarrel Avenue

For the street segments that did not have any available speed data, the methodology suggested the output speeds that were recommended based on the data that was available. The final speeds are not listed but the suggested output is as described.

Rounded Down 50th percentile speed:

  1. Arapahoe Avenue from Folsom Street to 28th Street
  2. Baseline Road from Mohawk Drive to Foothills Parkway
  3. Kalmia Avenue from 26th Street to 28th Street
  4. Gillaspie Drive from Greenbriar Boulevard to Table Mesa Drive
  5. 26th Street from McGuckin Way to Pearl Street
  6. University Avenue from Broadway to 17th Street

Closest 50th percentile speed:

  1. 32nd Street from Walnut Street to Prairie Avenue
  2. Spruce Street from 11th Street to 15th Street
  3. 11th Street from Walnut Street to Spruce Street
  4. 15th Street from Walnut Street to Spruce Street
  5. Sioux Drive from 55th Street to Baseline Road
  6. 55th Street from South Boulder Road to Sioux Drive
  7. Walnut Street from Folsom Street to 26th Street
  8. Jay Road from 26th Street to 28th Street

Rounded Down 85th percentile speed:

  1. Pearl Street from 47th Street to 50th Street

This map shows the difference in the recommended speed limits compared to the existing speed limits for the evaluated street segments. 8 streets segments have a recommended decrease of 10 mph, 41 have a recommended decrease of 5 mph, and 59 have no recommended change. 12 street segments were recommended for an increase of 5 mph and 2 were recommended for an increase of 10 mph. While city staff understand and respect the methodology used to develop recommended speed limits on evaluated segments, as part of its unwavering commitment to Vision Zero, the city is not planning to raise any posted speed limits at this time.

10mph Decrease

  1. Valmont Road from 47th Street to Airport Boulevard
  2. Baseline Road from US36 ramp to 30th Street
  3. Broadway from Lee Hill Drive to Foothills Highway
  4. Broadway from Redwood Avenue to Violet Avenue
  5. 47th Street from Diagonal Highway to Jay Road
  6. Colorado Avenue from Folsom Street to 30th Street
  7. Pearl Street from 17th Street to 20th Street
  8. Arapahoe Avenue from 6th Street to 9th Street

5 mph Decrease

  1. Colorado Avenue from 30th Street to Foothills Parkway
  2. Valmont Road from Airport Boulevard to 55th Street
  3. Baseline Road from Sioux Drive to Cherryvale Road
  4. Broadway from Iris Avenue to Redwood Avenue
  5. Iris Avenue from 26th Street to 28th Street
  6. Pearl Parkway from 30th Street to 47th Street
  7. Table Mesa Drive from Broadway to Moorhead Avenue
  8. Table Mesa Drive from Moorhead Avenue to South Boulder Road
  9. 9th Street from Walnut Street to Pearl Street
  10. 20th Street from Walnut Street to Pine Street
  11. 63rd Street from Lookout Road to Boulder Reservoir Water Treatment Plant Road
  12. Baseline Road from 30th Street to Mohawk Drive
  13. Monarch Road from 63rd Street to 71st Street
  14. Broadway from Violet Avenue to Lee Hill Drive
  15. Broadway from Balsam Avenue to Iris Avenue
  16. Pearl Street from 28th Street to 30th Street
  17. 9th Street from Balsam Avenue to Hawthorn Avenue
  18. Pine Street from 11th Street to 17th Street
  19. 17th Street from Walnut Street to Pine Street
  20. 19th Street from Violet Avenue to Yarmouth Avenue
  21. Dartmouth Avenue from cul-de-sac to Broadway
  22. Violet Avenue from 19th Street to 28th Street
  23. Valmont Road from Folsom Street to 30th Street
  24. 27th Way from Broadway to Baseline Road
  25. 30th Street from Valmont Road to Diagonal Highway
  26. 30th Street from Pearl Street to Valmont Road
  27. 30th Street from Arapahoe Avenue to Pearl Parkway
  28. Valmont Road from 30th Street to 47th Street
  29. 30th Street from Baseline Road to Colorado Avenue
  30. 55th Street from Baseline Road to Arapahoe Avenue
  31. Arapahoe Avenue from 9th Street to 17th Street
  32. Arapahoe Avenue from 17th Street to Folsom Street
  33. 20th Street from 2879 aley to 19th Street
  34. Folsom Street from Pearl Street to Pine Street
  35. Folsom Street from Arapahoe Avenue to Pearl Street
  36. Hawthorn Avenue from 9th Street to Broadway
  37. Walnut Street from 17th Street to Folsom Street
  38. University Avenue from Marshall Street to Broadway

No Change

  1. 55th Street from Flatiron Parkway to Arapahoe Avenue
  2. 71st Street from Winchester Circle to Mineral Road
  3. Iris Avenue from 19th Street to 26th Street
  4. 9th Street from Dewey Avenue to Balsam Avenue
  5. Mapleton Avenue from 4th Street to 9th Street
  6. 9th Street from Pearl Street to Mapleton Avenue
  7. Mapleton Avenue from 9th Street to Broadway
  8. 9th Street from Arapahoe Avenue to Walnut Street
  9. 20th Street from Pine Street to 2879 aley
  10. 63rd Street from Boulder Reservoir Water Treatment Plant Road to Boulder Reservoir Trail
  11. Broadway from Canyon Boulevard to Mapleton Avenue
  12. Broadway from Mapleton Avenue to Balsam Avenue
  13. Pearl Street from Folsom Street to 28th Street
  14. Baseline Road from Flagstaff Road to 9th Street
  15. 9th Street from Marine Street to Arapahoe Avenue
  16. Balsam Avenue from Broadway to 19th Street
  17. Edgewood Drive from 19th Street to Folsom Street
  18. 9th Street from Baseline Road to University Avenue
  19. Baseline Road from 9th Street to Broadway
  20. Walnut Street from 15th Street to 17th Street
  21. Pine Street from 17th Street to 20th Street
  22. Pine Street from 20th Street to Folsom Street
  23. Pine Street from Folsom Street to 28th Street
  24. 17th Street from University Avenue to Arapahoe Avenue
  25. 17th Street from Arapahoe Avenue to Walnut Street
  26. Table Mesa Drive from Vassar Drive to Lehigh Street
  27. Lehigh Street from Greenbriar Boulevard to Table Mesa Drive
  28. Moorhead Avenue from 27th Way to Table Mesa Drive
  29. Pearl Street from 7th Street to 11th Street
  30. Walnut Street from 7th Street to 11th Street
  31. Walnut Street from 11th Street to 15th Street
  32. Pearl Street from 15th Street to 17th Street
  33. Violet Avenue from Broadway to 19th Street
  34. 30th Street from Colorado Avenue to Arapahoe Avenue
  35. Table Mesa Drive from Lehigh Street to Broadway
  36. Airport Boulevard from Valmont Road to cul-de-sac
  37. Baseline Road from Foothills Parkway to Sioux Drive
  38. Kalmia Avenue from 28th Street to Foothills Parkway ramp
  39. Kalmia Avenue from 28th Street to ramp
  40. Lookout Road from Kalmia Avenue to 75th Street
  41. Spine Road from Longbow Drive to 63rd Street
  42. 63rd Street from Stazio Drive to Stazio Drive
  43. Lee Hill Drive from Broadway to 28th Street
  44. Yarmouth Avenue from Broadway to 28th Street
  45. Pearl Street from 20th Street to Folsom Street
  46. 19th Street from 20th Street to Iris Avenue
  47. Folsom Street from Colorado Avenue to Arapahoe Avenue
  48. Folsom Street from Pine Street to Valmont Road
  49. Folsom Street from Valmont Road to 26th Street
  50. Linden Avenue from Linden Drive to Broadway
  51. Lee Hill Drive from city limits to Broadway
  52. 19th Street from Iris Avenue to Violet Avenue
  53. 33rd Street from Arapahoe to Walnut Street
  54. Walnut Street from 30th Street to cul-de-sac
  55. 47th Street from Pearl Parkway to Valmont Road
  56. 47th Street from Valmont Road to Diagonal Highway
  57. Spine Road from city limits to Longbow Drive
  58. Gunbarrel Avenue from Spine Road to 63rd Street
  59. Iris Avenue from Broadway to 19th Street
  60. Aurora Avenue from 30th Street to Mohawk Road
  61. Glenwood Drive from Folsom Street to 30th Street
  62. 26th Street from Folsom Street to Jay Road

5 mph Increase*

  1. Pearl Parkway from 49th to Valmont Road
  2. 63rd Street from private road to monarch Road
  3. 63rd Street from Spine Road to Lookout Road
  4. 63rd Street from Gunbarrel Avenue to Spine Road
  5. 63rd Street from city limits to Gunbarrel Avenue
  6. 9th Street from Mapleton Avenue to Dewey Avenue
  7. 55th Street from Flatiron Parkway to Valmont Road
  8. 71st Street from Kalmia Avenue to Winchester Circle
  9. Balsam Avenue from 9th Street to Broadway
  10. 63rd Street from Arapahoe Avenue to Stazio Drive
  11. Spine Road from 63rd Street to Lookout Road
  12. Greenbriar Boulevard from Lehigh Street to Broadway

10 mph Increase*

  1. Pearl Parkway from 47th Street to 49th
  2. Lookout Road from 63rd Street to Gunpark Drive

*While city staff understand and respect the methodology used to develop recommended speed limits on evaluated segments, as part of its unwavering commitment to Vision Zero, the city is not planning to raise any posted speed limits at this time.