Operations Analysis for development projects in the City of Dublin

3.3 Operations Analysis

Projects anticipated to generate more than 50 vehicle trips during peak hours are required to perform an operations analysis. This includes assessing access points to the project site and key intersections where project-generated traffic may impact operations. This analysis supplements the trip generation/distribution documentation and site plan review. The specific requirements for the operations analysis are detailed below.

3.3.1 Data Collection and Study Periods

Traffic counts must be collected and included in the appendix. Existing counts may be used if they are less than two years old and traffic patterns have not significantly changed due to recent developments. The City may allow older or alternative data sources under atypical conditions, such as:

• Long-term roadway construction or closures.

• Significant disruptions to economic, employment, or institutional activity.

Approval for using alternative traffic counts must be obtained from the City Traffic Engineer or their designee.

Common Data Collection Rules:

• Timing: Conduct peak hour turning movement counts on Tuesdays, Wednesdays, or Thursdays during weeks without holidays, and under favorable weather conditions.

• School Session: Conduct counts when schools and colleges are in session, avoiding the first two weeks of the term. If collected during school breaks, methodology for including historical school traffic volumes must be approved by the City.

• Scope: Collect two-hour peak period volumes (vehicular, bicycle, and pedestrian) for all study intersections during weekday AM and PM periods. Additional periods (e.g., midday or weekends) may be specified by the City.

Early consultation with the City is required to determine the exact time periods for data collection, ensuring unnecessary analyses are avoided.

3.3.2 Study Scenarios

Intersection level of service (LOS) analyses must include the following scenarios:

1. Existing Conditions

2. Opening Year Conditions

3. Opening Year Plus Project Conditions (project-generated traffic added to opening year volumes).

4. Cumulative Conditions (based on the current cumulative year travel demand model).

5. Cumulative Plus Project Conditions (project-generated traffic added to cumulative traffic volumes).

For phased projects, an interim year analysis may be required for each phase’s opening. The City Traffic Engineer will determine the necessity of such analyses.

3.3.3 Future Traffic Volume Forecasting Methodology

Forecast future traffic volumes using:

• Local or regional travel demand models reflecting current land use and planned improvements (where programming or funding is secured).

• The closest forecast model year if a general plan build-out model is unavailable.

Any modifications to accommodate the project must be clearly identified in the Traffic Impact Analysis (TIA). If no travel demand model is available, historical growth rates or trends may be used, subject to City approval.

3.3.4 Operations Analysis Methodology

Evaluate LOS for all study intersections under the scenarios listed in Section 3.3.2. The analysis must:

• Use the latest Highway Capacity Manual (HCM) methodology.

• Be conducted with City-approved software (e.g., Vistro, Synchro, HCS).

3.3.5 Level of Service Standards

LOS is a performance measure that describes congestion levels, ranging from A (free-flowing) to F (highly congested). The City of Dublin’s LOS standards are:

• LOS D or better for most signalized intersections.

• LOS E or better within the Downtown Dublin Specific Plan area.

3.3.5.1 Signalized Intersections

Adverse traffic operations are identified when project traffic causes:

• LOS degradation beyond LOS D (outside Downtown) or LOS E (within Downtown).

• A delay increase of 6+ seconds at intersections already operating at LOS E.

• For LOS F intersections:

  • An increase in overall volume-to-capacity (V/C) ratio of 0.03 or more.

  • An increase in critical movement V/C ratio of 0.05 or more.

Routes of regional significance must meet the Tri-Valley Transportation Plan’s Multimodal Transportation Service Objective (MTSO) of LOS E or better.

3.3.5.2 Unsignalized Intersections

Unsignalized intersections should meet LOS D (outside Downtown) and LOS E (within Downtown). Adverse impacts are identified when project traffic causes:

• LOS degradation below acceptable thresholds, triggering the California Manual on Uniform Traffic Control Devices (MUTCD) peak hour signal warrant.

• 10+ additional vehicles to the critical movement at sub-threshold intersections, triggering MUTCD signal warrant.

Delay Metrics:

• All-Way Stop and Roundabout: Use overall intersection delay.

• Two-Way Stop Controlled: Use worst approach delay.

Improvements to unsignalized intersections may include changes to traffic control (e.g., yield, roundabout, or signal installation). Signal installation is subject to City discretion.

3.3.6 Additional Analysis Requirements

In addition to LOS, the analysis must include the following:

1. Vehicle Queuing:

• Examine outbound queuing at project driveways and note deficiencies/conflicts with circulation.

• Assess turn pocket storage adequacy at off-site intersections using 95th percentile queues.

2. Pedestrian Circulation:

• Assess safety and accessibility impacts on existing and planned sidewalks, crosswalks, and pedestrian facilities within a quarter-mile radius or connecting to transit stops.

• Determine consistency with adopted pedestrian policies and programs.

3. Bicycle Circulation:

• Evaluate safety and accessibility impacts on bikeways and facilities within a quarter-mile radius or connecting to transit stops.

• Assess consistency with adopted bicycle system plans, policies, or standards.

• Confirm compliance with City bicycle parking requirements.

4. Transit Circulation:

• Assess impacts on transit routes, facilities, and user safety within a quarter-mile radius.

5. Consistency with Policies:

• Evaluate conflicts with the City’s Complete Streets and Traffic Safety policies.

6. Metropolitan Transportation Service Objectives (MTSOs):

• Analyze impacts on MTSOs for routes of regional significance per the Tri-Valley Transportation Plan.

7. Additional Analyses:

• City staff may require supplemental studies, such as passenger or freight loading demand analyses.

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