Speed Management

Traffic Calming Treatments

The methodology for selecting traffic calming treatments uses a data-informed, equity-focused approach that considers crash history, characteristics of individual streets and surrounding neighborhoods, and speed data to proactively identify residential streets for potential speed mitigation interventions.

This methodology has been applied to all Level 1 and Level 2 streets in Austin (similar to "residential" and "collector" streets, respectively) as classified in the Austin Strategic Mobility Plan (ASMP).

Traffic Calming Methodology

The traffic calming methodology focuses on neighborhood streets, considering, ranking, and funding traffic calming devices under this general framework.

• Speed and volume data will be collected throughout the year, with requests opened under two cycles:
  • 60 in Round A (April) and 60 in Round B (October) from resident requests.
  • 120 per year from Vision Zero crash and street width rankings.
• Each cycle is a combination of locations generated from street width/crash history and resident input (see details below in Step 1).
  • Number per cycle is subject to funding, staffing, or contract capacity.
  • Local streets and residential collectors are eligible if they meet these criteria:
  • At least 60% adjacent residential use and
  • Daily volume (ADT) below 10,000

Those not meeting the eligibility criteria above could be addressed through improvements in collaboration under other initiatives.

• Pedestrian crossing program
• Systemic Safety, Rapid Response and other Vision Zero (VZ) projects
• Dynamic Speed Display Devices (DSDDs)
• Non-residential Speed Management

The traffic calming methodology takes a hybrid approach to analyze citywide speeding and identify streets for potential speeding issues using objective criteria. The program methodology includes three steps:

Step 1 - Citywide screening to select speed study locations

The City updated its selection criteria for speed study locations to incorporate additional public input. A total of 120 speed study locations will be selected twice a year for consideration for future speed management projects. Beginning in April and October of each calendar year, the City will accept public requests for speed studies. 

• During each request period, staff will allow residents to submit speed study requests. The City will collect up to 60 streets each cycle. Street submissions will be considered in the order they were received. After 60 streets are requested, the resident must resubmit their request during the next intake cycle if the request was not accepted.
• Once a year, staff will select the remaining 120 streets using street-width and crash-history data to predict and screen for streets most likely to experience egregious speeding.
• Speed study locations will be announced once a year based on this predictive model.

 

Street Width and Crash History

The methodology begins with an objective, data-driven approach to predict and screen streets for those most likely to experience egregious high-end speeds, using street width and crash history as inputs.

• Crashes using the new VZ methodology of counting only the worst injury in a single crash instead of counting all injuries in a single crash.
• Street width using the department's available database information, verified with field measurements and corrected as needed.
• Distribute scoring to 60% street width and 40% crashes. Scoring will be applied linearly. Tiers can be used if the data is skewed significantly. For crashes, scoring will be applied per mile (severe crashes per mile will receive additional consideration).
• Generate 120 streets to count each year.

 

Resident Input

To maintain expected levels of customer service, TPW must ensure residents can voice their concerns and that the department responds. While street width and crash history provide reliable predictors, residents may identify study locations with egregious speeding that these factors do not always predict.

• Collect resident input via Customer Service Requests (CSRs) from the Austin 3-1-1 system or Community Assistance Forms (CAFs).
• Take input until the limit of 60 locations per cycle is reached.
  • All residential streets identified through resident input will be counted, regardless of perceived eligibility, except for those already collected in the previous 3 years. This is done to remove bias by denying counts that could indicate an unknown speeding concern, and to ensure the City responds to residents' input by collecting data.
  • City engineering staff will monitor request lists to distribute requests per cycle when an excessive concentration of requests occurs in a specific area.
• Once the 60 limit is reached, residents will need to contact TPW during the next cycle.
• Communication with residents:
  • 3-1-1 intake process.
  • The department will discuss the methodology and any concerns with residents as needed to clarify the process and determine whether they can be addressed outside the competitive traffic calming process.

Step 2 - Ranking for Funding

The second part of the methodology focuses on which streets to prioritize for funding, using crash, speed, volume, and community context as data inputs. All streets from previous speed study cycles over the past three years, plus current-year selections, will be ranked for funding.

Factors for Ranking

• Measured Speeds – 35%
  • Use the 85th percentile to determine speeding concerns based on prevailing operating speed.
  • Speed remains the factor most contributing to serious injuries and fatalities.
• Volume of Egregious Speeding – 25%
  • Focuses mitigation on streets with the highest combination of speed and volume.
• Context – 20%
  • Presence of sidewalks
    • Most points for streets with no sidewalks.
    • Fewer points if the sidewalk is on one side of the street.
    • Zero points for sidewalks on both sides.
  • Bicycle facilities (modified)
    • Points for no bicycle facilities.
    • Additional points for being on a bicycle network without existing facilities.
  • Proximity to existing transit (modified)
    • Points for location with transit route.
    • Zero points for a location without a transit route.
  • Placement in an Equity Analysis Zone (EAZ)
    • Point scale for EAZ of the street segment to be applied.
  • Proximity to community destinations (schools, parks and libraries)
    • Point scale for relative proximity to nearby destinations.
  • Level 1 and 2 streets with:
    • At least 60% adjacent residential
    • Average daily trips (ADT) below 10,000
• Crashes – 20%

 

Process for Ranking

All streets from previous cycles over the past three years, plus the 240 locations, are initially ranked according to the factors above. Approximately five to 15 streets will be selected for projects per year based on available funding, staffing, or contract capacity.

Step 3 - Expert panel review and project selection

The City's transportation engineering staff performs a detailed analysis of the streets advanced from Step 2. The panel considers all available information, including additional street or area context (e.g., on-street/occupied parking, street width, and driveway density), all documented crashes, travel patterns, other City of Austin work planned for the area, and the balance between Step 1 criteria and documented excessive speeds. Based on this review, available funding, and program resources, project locations for speed mitigation treatments will be selected.

Final projects are subject to change based on field constructability, final construction cost, or other engineering determinations. Individual scopes of work for each selected street will be determined based on the department's understanding of current and emerging best practices for speed reduction strategies.