Active Transportation Plan Impact Evaluation Guidelines Following the Council-approved initiation of any new Active Transportation Plan (ATP) project, and when parking or traffic impacts are identified during the preliminary engineering phase (30% design), staff will return to the City Council to present the final 30% design, identified impacts, and potential trade-offs. At that meeting, the Council will determine whether the project should undergo a detailed impact analysis tailored to its specific impacts. This level of analysis requires a degree of design detail that is available only once the 30% design phase has been completed.
The detailed impact analysis described in these guidelines is intentionally scheduled for this phase of a project because at this phase, the City is advancing a concept from the ATP into preliminary design. It does not approve final plans or commit to construction.
The purpose of this early design effort is to translate a plan-level concept into a specific layout that defines lane configurations, parking, intersection control, and other geometric and operational details.
A 30% level of design is necessary to evaluate traffic and parking impacts with technical accuracy because traffic analysis tools, such as Synchro, TransCAD, Cube, or Inrix- based models, require defined lane assignments, turn pockets, signal phasing, parking layouts, and other project features not known prior to 30% design in order to produce meaningful estimates of delay, queues, diversion patterns, and parking utilization.
By conducting a detailed analysis at the 30% phase, the City balances accuracy with flexibility. A complete set of 30% design plans is sufficient for accurate modeling and is early enough in the design process to allow the Council to call for modifications or discontinue the project if the identified impacts are unacceptable. In addition, tying the analysis to the identification of parking or traffic impacts at 30% ensures that funding is focused on projects where the preliminary design reveals meaningful operational or parking impacts, rather than expending significant resources on every concept in the ATP, regardless of its risk profile.
Accordingly, if the Council requests an impact analysis following the 30% phase, then additional budget must be approved for the project’s Engineering Services Consultant to manage data collection and to evaluate the 30% design within the context of the City’s transportation network through traffic or parking analysis.
The tasks below summarize the scope of what could potentially be required for project impact analysis. Following the completion of 30% design for impacted projects, the Consultant will prepare a cost estimate for transportation analysis, which will also be presented to the Council for consideration when the Council reviews the 30% plans.
If Council supports this approach, staff will incorporate this impact evaluation framework into the final Active Transportation Plan as an internal policy that then applies to new ATP projects.
The tasks below may not apply to all projects, but it is assumed that impact analysis would roughly equate to 10% of project construction costs.
Task 1. Data Collection and Analysis Memorandum
Cost: $5,000 - $10,000
Prepare a memorandum describing the proposed approach to data collection and analysis. The memo will list all relevant data to be collected based on the project’s determined impacts and document sources, formats, and methods. This could include signal phasing, vehicle, pedestrian, and bicycle counts, an inventory of existing traffic control devices, or an inventory of parking supply. It will specify which transportation network or traffic operation elements, such as intersection delay, roadway segment operations, or parking, each dataset will support. The draft memorandum will be submitted to City staff for review before initiating data collection.
Task 2. Initial Data Collection
Cost: $15,000 - $30,000
• Obtain commercially available origin–destination data, through providers such as StreetLight, Inrix, or Replica for the project area, including both peak periods.
Collect turning-movement counts at project area intersections for both peak periods, including vehicle, pedestrian, and bicycle volumes, right-turn-on-red movements, and initial queues at signalized intersections.
• Conduct a field visit of the project site and broader study area to verify existing and planned facilities identified in the data collection tasks, confirm any facilities constructed since prior programming documents, and investigate unusual trends in traffic patterns.
Task 3. Traffic Operations Analysis
Cost: $20,000 - $40,000
• Document existing conditions based on collected counts and field observations.
Results will be summarized in narrative text, Level of Service (LOS) tables, figures visualizing lane configurations, traffic controls, and volumes, and supporting calculation outputs. If appropriate for evaluating the impacts of interest, speeds along the project area will be estimated and validated based on the City’s latest Engineering Traffic Survey, and queue lengths in dedicated turn lanes and through lanes between intersections under gridlock conditions will be evaluated. • Develop and refine Synchro traffic models to represent Existing and Existing-Plus- Project conditions. The models will be used to identify any adverse or significant impacts associated with the proposed project improvements. • Assess proposed intersection and corridor layouts for accessibility, including lane widths and turning radii, and identify opportunities for new or modified traffic control devices to support operations and safety.
• Develop recommendations to address identified potential operational impacts.
Task 4: Parking Impact Analysis (If needed)
Cost: $5,000 - $15,000
• Prior to conducting a parking survey, develop a geodatabase of on-street parking supply along the project area. The database will count, by block face, the number of spaces, as well as all applicable parking regulations, such as permits. The initial inventory will rely on the City’s GIS database, aerial imagery, and street-level photography, then verified in the field, and summarized in an exhibit that depicts curb conditions and the total existing parking supply.
• Perform parking occupancy counts at 30-minute intervals by block face during typical weekday midday (noon–2:00 p.m.) and evening (8:00–10:00 p.m.) periods, and on a Saturday to represent weekend conditions.
• Compare parking supply changes associated with the project design to observed parking demand to quantify the number of on-street spaces affected. The analysis will include spaces in front of nearby properties within a 500-foot buffer of the affected spaces to determine potential redistribution and broader neighborhood impacts.
Task 5: Impact Report
Cost: $5,000 - $10,000
The combined work will result in a set of findings and recommendations on specific traffic operations and parking impacts resulting from the project. The report will be used to inform potential further project development and frame public communications. The report will be evaluated by the City Council to assess the extent of the impacts and consider whether the project’s preliminary design should be modified to minimize the learned impacts or discontinued entirely.